EP4673043A1

EP4673043A1 - Array of electrodes usable for conducting an impedance measurement examination of the skin of a person and device for conducting said examination including said array of electrodes

Info

Publication number: EP4673043A1
Application number: EP24713537.9A
Authority: EP
Inventors: Ludovico MINATI; Davide ANTICHI; Marco MURACCINI; Renato COLOGNATO
Original assignee: Alma Magistra SRLS
Current assignee: Alma Magistra SRLS
Priority date: 2023-03-02
Filing date: 2024-02-19
Publication date: 2026-01-07
Also published as: IT202300003807A1; WO2024180573A1

Abstract

The invention refers to a device for conducting an impedance analysis of a per- son's skin by stimulating the skin not only at different frequencies, as already occurs in the state of the art, but also with pairs of electrodes at different mutual distances. Since the depth of penetration of an excitation signal into the skin varies as a function of the distance between the delivery electrode in which the ex- citation signal is delivered and the return electrode from which said signal is ac- quired, the arrangement in a single device of pairs of electrodes at different mu- tual distances allows the examination, using a single device, of skin layers at different depths. The invention also refers to a matrix of electrodes with which the device of the invention is equipped.

Description

Array of electrodes usable for conducting an impedance measurement examination of the skin of a person and device for conducting said examination including said array of electrodes

Field of application of the invention

The present invention finds application in the dermatological clinic, cosmetics, wellness and aesthetic medicine sectors. The present invention concerns, in particular, both the examination of the skin of a patient in order to allow a doctor or a qualified operator to express a judgment of a clinical, aesthetic or functional nature regarding it (such as for example the recognition of a pathological condition or the cause of a blemish), and the monitoring of the skin in order to observe the evolution over time of the physiological conditions of the same, possibly in response to a specific treatment.

More precisely, the present invention refers to a device using which a person can conduct an impedance measurement examination of his own skin by stimulating the latter at different frequencies and with pairs of electrodes at different mutual distances, and possibly send the result of said examination to a doctor (such as a dermatologist), a beautician or a qualified operator, in order to allow the latter to evaluate and follow over time the response to specific treatments aimed, for example, at modifying the level of skin hydration and its tissue composition.

The present invention also refers to a matrix of electrodes with which the aforementioned device of the invention can be equipped.

Review of known art

As is known, a person's skin includes body tissues characterized by different impedances. By measuring the impedance of the skin at appropriate frequencies, a impedance spectrum across frequencies of the skin area under examination is obtained. Starting from this spectrum, using state-of-the-art mathematical models, it is possible to estimate the tissue composition of the epidermis and the underlying skin states. The tissue composition of the skin allows determining dermatological parameters such as, for example, the level of hydration of the skin and the relative percentage of fat mass and lean mass in the deeper skin layers. Current devices for conducting an impedance measurement test of a person's skin, i.e., suitable for generating an impedance spectrum across frequencies of the areas of skin under examination, include a pair of electrodes at a predetermined distance through which a small potential difference in alternating electric current is applicable to the area of skin under examination. The impedance of the tissues is determined by analyzing the attenuation of the excitation signals in their transit through the skin from one to the other electrode of the aforementioned pair.

Purpose of the invention

The aim of the present invention is to indicate a device through which it is possible to conduct an impedance measurement examination of the skin of a person by stimulating the skin not only at different frequencies but also at different mutual distances of the stimulation electrodes in contact with the skin, so that said device constitutes an improved variant of known devices of the same type.

Summary and advantages of the invention

The object of the invention is a device for conducting an impedance measurement examination of a person's skin, said device comprising:

• a support structure at which said device:

- can be grasped by a person

And

- when grasped by a person, can be brought into contact with the skin of said person in correspondence with an area of said skin to carry out an impedance test in said area;

• a plurality of pairs of electrodes, each pair of electrodes of said plurality including (i.e., "being constituted by") a delivery electrode (i.e., excitation) and a return electrode (i.e., measuring or receiving), in each pair of electrodes of said plurality, said delivery electrode or said return electrode coinciding respectively with said delivery electrode or with said return electrode of at least one other pair of electrodes of said plurality so that, in each pair of electrodes said plurality, said delivery electrode or said return electrode is in common with at least one other pair of electrodes of said plurality, said electrodes of each pair of said plurality being arranged in such a way that, by tracing a segment having as its ends the two electrodes of said pair:

- said segment does not intersect any segment having as its ends the two electrodes of each other pair of said plurality and

- no electrode of each other pair of said plurality lies on said segment, said delivery electrode and said return electrode of at least one pair of electrodes of said plurality lying at a mutual distance different from that at which said delivery electrode and said return electrode lie of at least one other pair of electrodes of said plurality, said device being wearable in contact with the skin of said person in correspondence with said area in such a way that said electrodes of each pair of said plurality are in contact with the skin of said person in correspondence with said area;

• generating means suitable for emitting excitation signals at a plurality of frequencies and at a plurality of amplitudes, said excitation signals preferably comprising sinusoidal waves, said generating means

- being connected to said delivery electrode of each pair of said plurality and

- being suitable for imparting said excitation signals into said delivery electrode of each pair of said plurality so that, when said electrodes of each pair of said plurality are in contact with the skin of said person in correspondence with said area and said generating means emit said excitation signals, delivering the latter into said delivery electrode of a pair of electrodes of said plurality, said excitation signals delivered in said delivery electrode propagate in the skin of said person in correspondence with said area, reaching said return electrode belonging to said pair of electrodes, or said return electrodes belonging to said pairs of electrodes if more than one, to which said delivery electrode belongs; • detection means suitable for acquiring said excitation signals, said detection means

- being connected to said return electrode of each pair of said plurality and

- being suitable for acquiring said excitation signals possibly received by said return electrode of each pair of said plurality, and for generating a frequency impedance spectrum of said excitation signals possibly acquired by said return electrode, so that, when the electrodes of said plurality are in contact with the skin of said person in correspondence with said area and said generating means emit said excitation signals, delivering the latter into said delivery electrode of a pair of electrodes of said plurality, said excitation signals are acquired by said detection means after having propagated in the skin of said person in correspondence with said area starting from said delivery electrode and having reached said return electrode belonging to said pair of electrodes, or to one of said pairs of electrodes if more than one, to which said delivery electrode belongs and said detection means generate said impedance spectrum across frequencies of said excitation signals acquired by said return electrode;

• a first memory suitable for containing said frequency impedance spectra generated by said detection means for said return electrode of each pair of said plurality, or a series of said frequency impedance spectra generated by said detection means for said return electrode of each pair of said plurality;

• means for controlling said generating means and said detection means, said control means being suitable for regulating the frequencies and amplitudes at which said generating means emit said excitation signals, said generating means being controlled by said control means in such a way as to impart said excitation signals emitted by them (i.e., by said generating means) into no more than one of said delivery electrodes at a time, so that at any instant of time said excitation signals can be delivered by said generating means into one and only one of said delivery electrodes, said detection means being controlled by said control means in such a way as to acquire said excitation signals emitted by said generating means and delivered into one of said delivery electrodes

- by no more than one of said return electrodes at a time, so that at any instant of time said excitation signals can be acquired by one and only one of said return electrodes and

- from said return electrode of said pair, if only one, or of one of said pairs, if more than one, of said plurality to which said delivery electrode belongs in which said generating means have delivered said excitation signals, said control means being suitable for storing in said first memory one or more said frequency impedance spectra generated by said detection means for said return electrode of each pair of said plurality;

• connection means suitable for establishing a connection between said device and an electronic device (preferably a smartphone) for the transmission of data, preferably by means of radio frequency electromagnetic waves, between said control means and said device, when said device is connected to said apparatus via said connection means, said control means being suitable for

- transmitting to said device said frequency impedance spectra stored in said first memory and for

- receiving from said device commands for activating said generating means and said detection means.

The device object of the invention, through the plurality of pairs of electrodes (also object of the invention and subsequently defined as "matrix of pairs of electrodes"), allows to conduct an impedance measurement examination of a person's skin by stimulating the skin not only at different frequencies but also with pairs of electrodes at different distances from each other.

This constitutes a notable advantage since the depth of penetration of the exci- tation signals into the skin varies as a function of the distance between the sending electrode into which the excitation signals are delivered and the return electrode from which said signals are acquired. More precisely, the greater the distance between the two aforementioned electrodes, the greater the depth of penetration of the excitation signals into the skin. Varying the distance between the electrodes (of a pair of electrodes) therefore varies the depth of the skin layers that can be examined. In light of what has been said, by passing excitation signals through the skin between (pairs of) electrodes at different distances, it is advantageously possible to estimate, using a single device (an object of the invention), the composition of skin layers at different depths.

By means of the connection means, the device object of the invention can transmit the measurements carried out, for example, to a smartphone in which a specific application (so-called "app") is installed to communicate the aforementioned measurements to a user of the device and the smartphone, and possibly to share the latter for example with a dermatologist or a qualified operator. The aforementioned application can also show the time trend of the aforementioned measurements. Finally, it is preferably through said application that the aforementioned user can give commands to the device.

Incidentally, the fact that the electrodes of each pair are arranged in such a way that, by tracing a segment having as ends the two electrodes of said pair, said segment does not intersect any segment having as ends the two electrodes of each other pair and any electrode of each other pair of electrodes lies on said segment, advantageously guarantees that the measurements carried out do not interfere with each other. Incidentally, given an "active" delivery electrode and a return electrode (i.e., with excitation signals emitted by said delivery electrode and acquired by said return electrode), a third "inactive" electrode placed between the two aforementioned active electrodes would interfere with the measurements carried out via the two active electrodes since said inactive electrode has a non-negligible area in contact with the skin and is by its nature conductive. The inactive electrode would therefore create a further conduction path of the electric current which could alter its spatial distribution compared to what was observed in the absence of said third electrode. The aforementioned contamination, by the inactive electrode, of the measurements carried out through the two active electrodes can be defined as "interference" of the inactive electrode on the measurements carried out through the two active electrodes.

Other innovative features of the present invention are illustrated in the following description and referred to in the dependent claims.

According to another aspect of the invention, said support structure comprises a wall (i.e. , a portion of the external surface of said support structure) at which said device, when gripped by said person, can be brought into contact with the skin of said person in correspondence with said area, said electrodes being in correspondence with at least a portion of said wall.

According to another aspect of the invention, said wall comprises at least one concavity and/or at least one convexity at least in correspondence with said portion thereof.

According to this aspect of the invention, the fact that the electrodes are arranged on an at least partially concave and/or convex surface advantageously facilitates the conduct of an impedance test in non-flat areas of the skin. In fact, in correspondence with said (non-flat) areas, if the electrodes lie on a plane, it may be difficult to place the device of the invention on the skin in such a way that all the electrodes are in contact with the skin in said area.

According to another aspect of the invention, each of said electrodes is at least partially convex in such a way that, when said device, in correspondence with said wall, is pressed against the skin of said person in correspondence with said area, said electrodes push the skin inwards compared to the position assumed by the skin in the absence of pressure, so as to advantageously create a curvature and increase the contact area of each electrode with the skin.

According to this aspect of the invention, the risk that the electrodes do not come into contact with the area of the skin under examination is advantageously lower when the device of the invention is brought into contact with said area in correspondence with the aforementioned wall thereof.

According to another aspect of the invention, said generating means include:

• an oscillator suitable for emitting periodic signals, preferably of a sinusoidal type, said control means being suitable for regulating the frequency at which said oscillator emits said periodic signals;

• a variable gain amplifier, said oscillator being connected to said amplifier so as to be suitable for imparting said periodic signals into said amplifier, said control means being suitable for regulating the gain of said amplifier and consequently the amplitude of said periodic signals as amplified by said amplifier, said amplifier being suitable to deliver said amplified periodic signals into said delivery electrode of at least one pair of electrodes of said plurality, said amplified periodic signals therefore corresponding to said excitation signals emitted by said generating means.

Incidentally, to "turn off" a delivery electrode it is sufficient for the control means to set to zero the gain of the amplifier that delivers its signals into said electrode. According to another aspect of the invention, alternative to the previous one, said generating means include:

• a second memory suitable for containing at least one frequency table, said control means being suitable for entering frequency values into said table;

• a synthesizer suitable for simultaneously emitting multiple periodic signals, preferably of the sinusoidal type, at frequencies contained in said table;

• if said synthesizer is of the digital type, a digital to analog converter, said synthesizer being connected to said converter so as to be suitable for imparting said multiple periodic signals into said converter;

• a variable gain amplifier, said synthesizer, if of the analog type, or said converter, if present, being connected to said amplifier so as to be suitable for transmitting said multiple periodic signals into said amplifier, said control means being suitable for regulating the gain of said amplifier and consequently the amplitude of said multiple periodic signals as amplified by said amplifier, said amplifier being suitable to deliver into said delivery electrode at least one pair of electrodes of said plurality called multiple amplified periodic signals, said amplified periodic signals therefore corresponding to said excitation signals emitted by said generating means.

Advantageously, since the synthesizer can "synthesize" multiple frequencies at the same time, other factors being equal, the conduct of an impedance test using the device of the invention takes place in less time if the generating means include a synthesizer (according to this aspect of the invention) compared to the case in which the generating means comprise an oscillator (according to the previous aspect of the invention).

According to another aspect of the invention, if in said plurality of pairs of electrodes there is a first set of delivery electrodes that do not coincide with each other, said device comprises a line deselector (also known as "demultiplexer" or "demultiplexer"), said amplifier being connected to the input of said deselector so as to be suitable for imparting said excitation signals into said deselector, each of said delivery electrodes belonging to said first set being connected to an output of said deselector in such a way that each output of said deselector is connected to one and only one of said delivery electrodes belonging to said first set, said deselector being suitable for connecting its input to each of its outputs and to no more than one output at a time in such a way that said excitation signals can be transferred from said amplifier into said delivery electrode connected to the output of said deselector connected at the entrance of the latter, said amplifier being therefore suitable for transmitting said excitation signals into each of said delivery electrodes belonging to said first assembly through said deselector, said control means being suitable for selecting to which output of said deselector the input thereof is connected and consequently being suitable for selecting into which of said delivery electrodes belonging to said first set said excitation signals can be delivered from said amplifier for the via said deselector.

If the aforementioned first set of sending electrodes is present, the device object of the invention could include an oscillator or a synthesizer (as previously stated) for each sending electrode belonging to the first set or could include a single oscillator or synthesizer connected to the said deselector through, at least, an amplifier (as previously stated). Alternatively, in the absence of the deselector, the device object of the invention could include an oscillator or a synthesizer connected to all the delivery electrodes belonging to the first set through, at least, respective amplifiers (according to what was previously said) and to give the excitation signals in one and only one delivery electrode, it is sufficient for the control means to set the gain of the amplifiers connected to the other delivery electrodes to zero.

According to another aspect of the invention, said detection means include:

• a transconductance operational amplifier, said transconductance amplifier being suitable for acquiring from said return electrode of at least one pair of electrodes of said plurality said excitation signals received from said return electrode when the electrodes of said plurality are in contact with the skin of said person at said area and after said excitation signals have propagated in the skin of said person in correspondence with said area starting from said delivery electrode included in said pair of electrodes following a delivery by said amplifier included in said generating means in said electrode sending said periodic signals following their emission by said oscillator;

• an additional variable gain amplifier, said transconductance amplifier being connected to said further amplifier so as to be suitable for imparting into said further amplifier said excitation signals as amplified by said transconductance amplifier, said control means being suitable for regulating the gain of said further amplifier and consequently the amplitude of said excitation signals as further amplified by said further amplifier;

• a first "low pass" type filter, said further amplifier being connected to said first filter so as to be suitable for providing said further amplified excitation signals into said first filter;

• a quadrature demodulator, said first filter being connected to said demodulator so as to be suitable for imparting said excitation signals into said demodulator as filtered by said first filter, said demodulator being connected to said oscillator and being suitable for quadrature demodulating said excitation signals as filtered by said first filter using as reference frequency the frequency at which said oscillator emits said periodic signals;

• a second "low pass" type filter, the real output of said demodulator being connected to said second filter so that said demodulator is suitable for imparting into said second filter the real component of said excitation signals as filtered by said first filter;

• a third "low pass" filter, the imaginary output of said demodulator being connected to said third filter so that said demodulator is suitable for imparting into said third filter the imaginary component of said excitation signals as filtered by said first filter;

• a first analog-digital converter, said second filter being connected to said first analog-digital converter so as to be suitable for imparting into said first analog-digital converter the real component of said excitation signals as filtered by said second filter;

• a second analog-digital converter, said third filter being connected to said second analog-digital converter so as to be suitable for imparting into said second analog-digital converter the imaginary component of said excitation signals as filtered by said third filter, said first and second analog-digital converters being connected to said first memory and being suitable for transferring said real and imaginary components into the latter as sampled by said first and second analog-digital converters, so as to generate an impedance spectrum across frequencies of said input signals excitation when acquired from said return electrode by said transconductance amplifier.

According to another aspect of the invention, alternative to the previous one, said detection means include: a transconductance operational amplifier, said transconductance amplifier being suitable for acquiring from said return electrode of at least one pair of electrodes of said plurality said excitation signals received from said return electrode when the electrodes of said plurality are in contact with the skin of said person at said area and after said excitation signals have propagated in the skin of said person in correspondence with said area starting from said delivery electrode included in said pair of electrodes following a delivery by said amplifier included in said generating means in said electrode sending said multiple periodic signals following their emission by said synthesizer;

• a “low pass” type filter, said further amplifier being connected to said filter so as to be suitable for providing said further amplified excitation signals into said filter;

• an analog-digital converter, said filter being connected to said analog-digital converter so as to be suitable for imparting said excitation signals as filtered by said filter into said analogdigital converter;

• a discrete Fourier transform calculation module, said analog-digital converter being connected to said calculation module so as to be suitable for transmitting said excitation signals into said calculation module as sampled by said analog-digital converter, said calculation module being suitable for generating a frequency impedance spectrum of said excitation signals acquired by said return electrode by said transconductance amplifier, said calculation module being connected to said first memory and being suitable for transferring into the latter said impedance spectrum across frequencies of said excitation signals when acquired by said return electrode by said transconductance amplifier.

According to another aspect of the invention, if in said plurality of pairs of electrodes there is a second set of return electrodes that do not coincide with each other, said device comprises a line selector (also known as "multiplexer" or "multiplexer"), each of said return electrodes belonging to said second set being connected to an input of said selector in such a way that each input of said selector is connected to one and only one of said return electrodes belonging to said second set, said transconductance amplifier being connected to the output of said selector so as to be suitable for acquiring said excitation signals from said selector, said selector being suitable for connecting its output to each of its inputs and to no more than one input at a time in such a way that said excitation signals can be acquired by said transconductance amplifier from said return electrode connected to the input of said selector connected to the output of the latter, said transconductance amplifier being therefore suitable for acquiring said excitation signals from each of said return electrodes belonging to said second set through said selector, said control means being suitable for selecting to which input of said selector the output of the same is connected and consequently being suitable for selecting from which of said return electrodes belonging to said second set said excitation signals can be acquired by said transconductance amplifier via said selector.

If the aforementioned second set of return electrodes is present, the device object of the invention could include a transconductance amplifier (as previously stated) for each return electrode belonging to the second set or could include a single transconductance amplifier connected to the aforementioned selector.

According to another aspect of the invention, in said plurality of electrode pairs there is a first group of electrode pairs of said plurality comprising multiple electrode pairs of said plurality, all said pairs of electrodes of said plurality belonging to said first group sharing:

• said delivery electrode, so that there is a single delivery electrode common to all the pairs of electrodes belonging to said first group and to which said return electrode of each pair of electrodes belonging to said first group is coupled or

• said return electrode, so that there is a single return electrode common to all the pairs of electrodes belonging to said first group and to which said delivery electrode of each pair of electrodes belonging to said first group is coupled, said delivery electrode and said return electrode of each pair of electrodes belonging to said first group lying at a mutual distance different from that at which said delivery electrode and said return electrode lie of each other pair of electrodes belonging to said first group , in said plurality of pairs of electrodes there being at least a second group of pairs of electrodes of said plurality comprising multiple pairs of electrodes of said plurality, all said pairs of electrodes of said plurality belonging to said second group sharing:

• said delivery electrode, so that there is a single delivery electrode common to all the pairs of electrodes belonging to said second group and to which said return electrode of each pair of electrodes belonging to said second group is coupled or

• said return electrode, so that there is a single return electrode common to all the pairs of electrodes belonging to said second group and to which said delivery electrode of each pair of electrodes belonging to said second group is coupled, said delivery electrode and said return electrode of each pair of electrodes belonging to said second group lying at a mutual distance different from that at which said delivery electrode and said return electrode lie of each other pair of electrodes belonging to said second group , in each pair of electrodes belonging to said first group, both said delivery electrode and said return electrode being not in common with any pair of electrodes belonging to said second group, the number of said electrodes included in said first group coinciding with the number of said electrodes included in said second group, the mutual distance at which said delivery electrode and said return electrode lie (i.e., the distance between said delivery electrode and said return electrode) of each pair of electrodes belonging to said first group coinciding with the mutual distance at which said electrode lie delivery and said return electrode of a pair of electrodes belonging to said second group.

According to another aspect of the invention, for said return electrode of each pair of electrodes belonging to said first group, said control means, when the electrodes of said plurality are in contact with the skin of said person in correspondence with said area and said generating means deliver said excitation signals into said delivery electrode included in said pair, are suitable for:

• average between

- said frequency impedance spectrum generated by said detection means for said return electrode (of said pair belonging to said first group) and

- said frequency impedance spectrum generated by said detection means for the return electrode of the pair of electrodes belonging to said second group and in which said delivery electrode and said return electrode lie at the same mutual distance at which said delivery electrode lies and said return electrode of said pair belonging to said first group,

• store said average in said first memory,

• compare

- said frequency impedance spectrum generated by said detection means for the return electrode of the pair of electrodes belonging to said second group and in which said delivery electrode and said return electrode lie at the same mutual distance at which said delivery electrode lies and said return electrode of said pair belonging to said first group, • estimate a degree of similarity between

- said frequency impedance spectrum generated by said detection means for the return electrode of the pair of electrodes belonging to said second group and in which said delivery electrode and said return electrode lie at the same mutual distance at which said delivery electrode lies and said return electrode of said pair belonging to said first group and

• memorize said degree of similarity in said first memory, said first memory, for said return electrode of each pair of electrodes belonging to said first group, being therefore suitable to also contain:

• called the average between

- said frequency impedance spectrum generated by said detection means for the return electrode of the pair of electrodes belonging to said second group and in which said delivery electrode and said return electrode lie at the same mutual distance at which said delivery electrode lies and said return electrode of said pair belonging to said first group;

• said degree of similarity between

- said frequency impedance spectrum generated by said detection means for the return electrode of the pair of electrodes belonging to said second group and in which said delivery electrode and said return electrode lie at the same mutual distance at which said delivery electrode lies and said return electrode of said pair belonging to said first group, when said device is connected to said apparatus via said connection means, said control means being suitable for transmitting to said apparatus said averages and said degrees of similarity stored in said first memory.

In light of the above, the device can include two groups of electrodes with the pairs of electrodes at the same mutual distances (as specified above) and arranged, by way of example, one next to the other on the aforementioned wall of the subject device of invention. This constitutes an advantage since, to obtain a better estimate of the tissue composition of the skin, the control means can average the readings carried out by each group of electrodes and/or evaluate the degree of similarity between said readings in order to exclude electrodes the measurement carried out by which is unacceptable or most likely incorrect in light of the measurements carried out via the other electrodes.

Incidentally, if in the first (or equivalently in the second) group there is a single return electrode common to all the pairs of electrodes belonging to said group, generate the frequency impedance spectrum for the return electrode of each pair of electrodes belonging to the first (or second) group means generating the impedance aspects in frequency in correspondence with said single return electrode by sending to the latter excitation signals emitted in succession from all the sending electrodes of the pairs of electrodes belonging to the first (or second) ) group.

As mentioned previously, the electrodes of each pair are arranged in such a way that, by tracing a segment having as ends the two electrodes of said pair, said segment does not intersect any segment having as ends the two electrodes of each other pair and no electrode of each other pair lies on said segment. Incidentally, the aforementioned specification is reflected not only within each of the aforementioned groups of pairs of electrodes but also between one group and another, i.e., the electrodes of each pair of one of the two groups are arranged in such a way that, tracing a segment having as ends the two electrodes of said pair, said segment does not intersect any segment having as ends the two electrodes of each other pair of said group, nor of each pair of the other group, and no electrode of each other pair of said group, nor of each pair of the other group, lies on said segment. According to another aspect of the invention, said control means, when the electrodes of said plurality are in contact with the skin of a person in correspondence with said area, are furthermore suitable for:

• activating said generating means and said detection means, during a first predefined time interval, in such a way as to generate said impedance frequency spectra by acquiring excitation signals from said return electrode of each pair of electrodes belonging to said first group and from said return electrode of each pair of electrodes belonging to said second group,

• estimating said degree of similarity between said frequency impedance spectrum generated for said return electrode of each pair of electrodes belonging to said first group and said frequency impedance spectrum generated for said return electrode of the corresponding pair of electrodes belonging to said second group (that is, for said return electrode of the pair of electrodes belonging to said second group and in which said delivery electrode and said return electrode lie at the same mutual distance at which said delivery electrode and said return electrode of said pair belonging to said first group),

• estimating a degree of agreement between said two groups of pairs of electrodes on the basis of said degree of similarity between said frequency impedance spectrum generated for said return electrode of each pair of electrodes belonging to said first group and said frequency impedance spectrum generated for said return electrode of the corresponding pair of electrodes belonging to said second group (i.e., for said return electrode of the pair of electrodes belonging to said second group and in which said delivery electrode and said return electrode lie at the same mutual distance at which they lie said delivery electrode and said return electrode of said pair belonging to said first group) and

• memorizing said degree of agreement in said first memory, said first memory being therefore suitable to also contain said degree of agreement, when said device is connected to said apparatus through said connection means, said control means being suitable for transmitting to said apparatus said degree of agreement stored in said first memory. According to another aspect of the invention, said control means are also suitable for communicating to a user of said device, whenever said degree of agreement is estimated, whether said degree of agreement is higher or not higher than a first predefined limit value.

Advantageously, according to this aspect of the invention, whenever an impedance measurement test is carried out, the control means are suitable for signaling when using the device if the two groups of electrodes are in disagreement. In this case it is in fact advisable to repeat the impedance test.

According to another aspect of the invention, said control means are also suitable for

• operating said generating means and said detection means, during a second predefined time interval, in such a way as to try to generate frequency impedance spectra by acquiring excitation signals from said return electrode of each pair of electrodes of said plurality and for

• communicating to a user of said device whether the number of pairs of electrodes of said plurality for which it was possible to generate said frequency impedance spectrum is higher or not higher than a second predefined limit value.

Advantageously, according to this aspect of the invention, whenever an impedance measurement test is carried out, the control means are suitable for signaling when using the device whether a sufficient number of pairs of electrodes are in contact with the skin to conduct the aforementioned test. If a delivery or return electrode is in fact not in contact with the skin, it is not possible to generate the impedance spectrum across frequencies for said return electrode or for the return electrode belonging to the same pair to which said delivery electrode belongs.

• estimating the tissue composition of the skin in said area starting from said frequency impedance spectra stored in said first memory and for memorizing said tissue composition in said first memory, said first memory being therefore suitable to also contain said tissue composition, when said device is connected to said apparatus via said connection means, said control means being suitable for transmitting to said apparatus said tissue composition stored in said first memory.

Another object of the present invention is a matrix of electrode pairs (i.e., a plurality of electrode pairs, multiple electrode pairs considered as a whole), each pair of electrodes of said matrix including a delivery electrode and a return electrode, in each pair of electrodes of said matrix, said delivery electrode or said return electrode coinciding respectively with said delivery electrode or with said return electrode of at least one other pair of electrodes of said matrix so that, in each pair of electrodes said matrix, said delivery electrode or said return electrode is in common with at least one other pair of electrodes of said matrix, said electrodes of each pair of said matrix being arranged in such a way that, by tracing a segment having as ends the two electrodes of said pair:

• said segment does not intersect any segment having as its ends the two electrodes of each other pair of said matrix and

• no electrode of each other pair of said matrix lies on said segment, said delivery electrode and said return electrode of at least one pair of electrodes of said matrix lying at a mutual distance different from that at which said delivery electrode and said return electrode lie of at least one other pair of electrodes of said matrix, said matrix can be included in a device for conducting an impedance test of a person's skin, said device comprising:

• generating means suitable for emitting excitation signals at a plurality of frequencies and at a plurality of amplitudes;

• detection means suitable for acquiring said excitation signals, said matrix being included in said device in such a way that:

• said electrodes of each pair of said matrix can be brought into contact with the skin of said person in correspondence with said area; • said generating means

- are connected to said delivery electrode of each pair of said matrix and

- are suitable for imparting said excitation signals into said delivery electrode of each pair of said matrix so that, when said electrodes of each pair of said matrix are in contact with the skin of said person in correspondence with said area and said generating means emit said excitation signals, delivering the latter into said delivery electrode of a pair of electrodes of said matrix, said excitation signals delivered in said delivery electrode propagate in the skin of said person in correspondence with said area, reaching said return electrode belonging to said pair of electrodes, or said return electrodes belonging to said pairs of electrodes if more than one, to which said delivery electrode belongs;

• said detection means

- are connected to said return electrode of each pair of said matrix and

- are suitable for acquiring said excitation signals possibly received by said return electrode of each pair of said matrix, and for generating a frequency impedance spectrum of said excitation signals possibly acquired by said return electrode so that, when said electrodes of each pair of said matrix are in contact with the skin of said person in correspondence with said area and said generating means emit said excitation signals, delivering the latter into said delivery electrode of a pair of electrodes of said matrix, said excitation signals are acquired by said detection means after having propagated in the skin of said person in correspondence with said area starting from said delivery electrode and having reached said return electrode belonging to said pair of electrodes, or to one of said pairs of electrodes if more than one, to which said delivery electrode belongs and said detection means generate said impedance spectrum across frequencies of said excitation signals acquired by said return electrode, so that said device is suitable to allow the conduct of an impedance measurement examination of the skin of said person, in correspondence with said area, using said pairs of electrodes of said matrix.

Brief description of the figures

Further objects and advantages of the present invention will be clear from the following detailed description of examples of its implementation and from the attached drawings, given purely for explanatory and non-limiting purposes, in which:

- figure 1 shows, in a schematic plan view, a wall of a device according to the present invention, in correspondence with which (wall) the device comprises a plurality of pairs of electrodes for conducting an impedance measurement examination of a person's skin;

- figures 2 to 5 show, in schematic plan view, respective variants of the device of figure 1 ;

- figure 6 schematically shows some components of the device of figure 1 for providing excitation signals in the delivery electrodes of the aforementioned pairs of electrodes;

- figure 7 schematically shows a variant of the components of figure 6;

- figure 8 schematically shows a further element which could be part of the device of figure 1 , connectable (called further element) to the components of figure 6 or 7;

- figure 9 schematically shows other components of the device of figure 1 for the acquisition of excitation signals from the delivery electrodes of the aforementioned pairs of electrodes;

- figure 10 schematically shows a variant of the components of figure 9;

- figure 11 schematically shows a further element which could be part of the device of figure 1 , connectable (called further element) to the components of figure 9 or 10; - figure 12 schematically shows the connections of some of the above-mentioned components of the device of figure 1 , with a control unit thereof.

Detailed description of some preferred embodiments of the invention

In the remainder of this description a figure may also be illustrated with reference to elements not expressly indicated in that figure but in other figures. The scale and proportions of the various elements depicted do not necessarily correspond to the real ones.

Figure 1 shows, in partial view, a device 1 , object of the invention, by means of which it is possible to conduct an impedance measurement examination of a person's skin. The device 1 includes a support structure at which the device 1 can be grasped by a person so that it can be brought into contact with the skin of said person in the area of the skin being examined (impedance measurement). More precisely, the device 1 can be grasped by a person so that it can be brought into contact with the skin area of said person being examined in correspondence with a wall 2 of the device 1 .

The device 1 comprises a plurality of pairs of electrodes located in correspondence with at least a portion of the wall 2. Each of the said pairs of electrodes comprises a delivery electrode 3 and a return electrode 4. In each of the aforementioned pairs of electrodes, the delivery electrode 3 or return electrode 4 coincide respectively with the delivery electrode 3 or with the return electrode 4 of at least another of the aforementioned pairs of electrodes so that, in each of the pairs of electrodes, the electrode delivery electrode 3 or the return electrode 4 is in common with at least one other pair of electrodes. The electrodes 3 and 4 of each pair are arranged on the wall 2 in such a way that, by tracing a segment 5 (dashed in figure 1 ) having as its ends the electrodes 3 and 4 of said pair, said segment 5 does not intersect any other segment 5 (i.e., no segment having as its ends the electrodes 3 and 4 of each other pair of electrodes) and no electrode 3 or 4 of each other pair of electrodes lies on said segment 5. The delivery electrode 3 and the return electrode 4 of at least one of the aforementioned pairs of electrodes lie at a mutual distance different from that at which the delivery electrode 3 and the return electrode 4 lie of at least one other pair of electrodes.

The wall 2 preferably includes at least one concavity and/or at least one convexity at least in correspondence with the aforementioned portion of wall 2 in correspondence with which the electrodes 3 and 4 are positioned.

In figure 1 the device 1 is shown as including a number of electrode pairs equal, by way of example, to eight. Said eight pairs of electrodes preferably have the return electrode 4 in common. The device 1 therefore includes, by way of example, eight delivery electrodes 3 and a single return electrode 4 common to all eight pairs of electrodes 3 and 4. In other words, the return electrode 4 of one of the eight pairs of electrodes coincides with the return electrode 4 of each of the remaining seven pairs of electrodes. The eight delivery electrodes 3 are preferably distributed around the single return electrode 4 so that the latter occupies an almost central position in the set of electrodes 3 and 4 included in the device 1 . The eight segments 5 which respectively connect the eight delivery electrodes delivery 3 to the single return electrode 4 are therefore distributed almost radially around the return electrode 4 (corresponding to an end common to all eight segments 5). The eight segments 5 preferably have different lengths from each other. More precisely, the distance between the delivery electrode 3 and the return electrode 4 of one of the eight pairs of electrodes is preferably different from the distance between the delivery electrode 3 and the return electrode 4 of each of the other seven pairs of electrodes.

Equivalently to what has been described above, the device 1 could comprise eight return electrodes 4 distributed around a single delivery electrode 3 common to all eight pairs of electrodes.

The device 1 , in correspondence with the wall 2, can be brought into contact with the skin of a person in correspondence with the area of the skin being subjected to impedance measurement examination in such a way that the electrodes 3 and 4 of each of the pairs of electrodes are in contact with the skin in correspondence with the aforementioned area. Each of the electrodes 3 and 4 is preferably at least partially convex in such a way that, when the device 1 , in correspondence with the wall 2, is pressed against the skin of a person in correspondence with the area of the skin being subjected to impedance measurement examination, the electrodes 3 and 4 push the skin inwards with respect to the assumed position of the skin in the absence of pressure, so as to create a curvature and increase the contact area of each electrode 3 or 4 with the skin.

As will be illustrated in more detail later in this description, the device 1 includes components (previously qualified as "generating means") suitable for emitting excitation signals (preferably sinusoidal waves) at a plurality of frequencies and at a plurality of amplitudes. Said components, which can be classified as "emitters", are connected to the delivery electrode 3 of each of the pairs of electrodes and are suitable for transmitting the excitation signals (when emitted) into the delivery electrode 3 of each of the pairs of electrodes. When the electrodes 3 and 4 of each of the pairs of electrodes are in contact with the skin of a person in correspondence with the area of the skin being subjected to impedance measurement examination and the emitting components emit excitation signals, transferring the latter into the delivery electrode 3 of a of the pairs of electrodes, the excitation signals delivered to the delivery electrode 3 of said pair propagate into the skin in correspondence with the aforementioned area, reaching the return electrode 4 belonging to said pair (or, if the delivery electrode 3 of said pair is common to several pairs of electrodes, reaching the return electrodes 4 belonging to the pairs of electrodes to which said delivery electrode 3) belongs.

Device 1 includes further components (previously qualified as "detection means") suitable for acquiring the excitation signals (when) emitted by the emitting components. Said further components, which can be classified as "acquisitioners", are connected to the return electrode 4 of each of the pairs of electrodes and are suitable for acquiring the excitation signals possibly received by the return electrode 4 of each of the pairs of electrodes and for generating a frequency impedance spectrum of the excitation signals possibly acquired by the return electrode 4 of said pair. When the electrodes 3 and 4 of each of the pairs of electrodes are in contact with the skin of a person in correspondence with the area of the skin being subjected to impedance measurement examination and the emitting components emit excitation signals, transferring the latter into the delivery electrode 3 of a of the pairs of electrodes, the excitation signals are acquired by the acquisition components after having propagated in the skin in correspondence with the aforementioned area and after reaching the return electrode 4 belonging to said pair (or, if the delivery electrode 3 of said pair is common to several pairs of electrodes, after reaching the return electrode 4 belonging to one of the pairs of electrodes to which said delivery electrode 3 belongs), and the acquisition components generate a frequency impedance spectrum of the excitation signals acquired from called return electrode 4.

The device 1 comprises a unit 6 (visible in figure 12 and preferably including a microprocessor) connected to the above-mentioned emitter components and acquisition components of the device 1 for their control. More precisely, the unit 6 is suitable for regulating the frequencies and amplitudes at which the emitting components emit the excitation signals. The emitting components are furthermore controlled by the unit 6 in such a way that the excitation signals emitted by them are delivered into no more than one delivery electrode 3 at a time, so that at any instant of time the excitation signals can be delivered by the emitter components of the device 1 in one and only one of the delivery electrodes 3. The acquisition components are controlled by the unit 6 in such a way that the excitation signals emitted by the emitter components and delivered into one of the delivery electrodes 3 are acquired by the acquisition components from no more than one return electrode 4 at a time, so that at any instant of time the excitation signals can be acquired from one and only one of the return electrodes 4, and from the return electrode 4 belonging to the pair of electrodes , if only one, or to one of the pairs of electrodes, if more than one, to which said delivery electrode 3 belongs, in which the emitting components have conferred the excitation signals. The device 1 includes a first memory 7 (visible in figure 12) in which the unit 6 is suitable for memorizing, for the return electrode 4 of each pair of electrodes, one or more frequency impedance spectra (preferably a series of frequency impedance spectra) generated by the acquisition components of the device 1 for said return electrode 4. The device 1 also includes appropriate components 8 (visible in figure 12 and included in the previously mentioned "connection means") through which it is possible to establish a connection between the device 1 and an electronic device 9 (also visible in figure 12 and preferably corresponding to a smartphone) for the transmission of data between the unit 6 and the device 9. The components 8 preferably include an antenna and the data transmission between the unit 6 and the device 9 preferably takes place via radio frequency electromagnetic waves. When the device 1 is connected to the device 9 through the components 8, the unit 6 is suitable for transmitting the frequency impedance spectra stored in the memory 7 to the device 9 and for receiving commands from the device 9 to activate the emitting components and purchasing components.

In light of what has been said, the device 1 , through the aforementioned plurality of pairs of electrodes (also the subject of an invention and previously also identified with the expression "matrix of pairs of electrodes") advantageously allows to conduct a impedance measurement examination of a person's skin by stimulating the skin with excitation signals not only at different frequencies but also with pairs of electrodes 3 and 4 at different mutual distances.

Figure 2 shows, in partial view, a variant of the device 1 in which the electrodes 3 and 4 are placed in correspondence with the aforementioned wall portion 2 with a different spatial distribution compared to that shown in figure 1 . More precisely, although the number of pairs of electrodes is still equal, for example, to eight, the eight pairs of electrodes still preferably have the return electrode 4 in common (so that there are still eight delivery electrodes 3 and a single return electrode 4 common to all eight pairs of electrodes) and the eight segments 5 which respectively connect the eight delivery electrodes 3 to the single return electrode 4 are still distributed almost radially around the return electrode 4 (corresponding to an end common to all the eight segments 5), in the variant of the device 1 shown, in partial view, in figure 2 the delivery electrodes 3 are placed along a spiral 10 in correspondence with the pole of which the return electrode 4 is placed (common to all eight pairs of electrodes).

Similarly to what was said with reference to figure 1 , also in the variant of the device 1 shown in figure 2 the eight segments 5 preferably have different lengths from each other. More precisely, the distance between the delivery electrode 3 and the return electrode 4 of one of the eight pairs of electrodes is preferably different from the distance between the delivery electrode 3 and the return electrode 4 of each of the other seven pairs of electrodes. The variant of the device 1 shown in figure 2, similarly to what was said for the device 1 , could include eight return electrodes 4 distributed, along a spiral, around a single delivery electrode

3 common to all eight pairs of electrodes and positioned corresponding to the pole of spiral 10.

Figure 3 shows another variant of the device 1 in which in the aforementioned plurality of electrode pairs 3 and 4 there is at least a first group 11 of electrode pairs 3 and 4 of the said plurality comprising more than one electrode pair 3 and

4 of said plurality, and a second group 12 of pairs of electrodes 3 and 4 of said plurality comprising more than one pair of electrodes 3 and 4 of said plurality. Preferably, the pairs of electrodes 3 and 4 can be divided into the aforementioned groups 1 1 and 12.

All the pairs of electrodes 3 and 4 belonging to the group 11 share a single delivery electrode 3 (so that there is a single delivery electrode 3 common to all the pairs of electrodes 3 and 4 belonging to the group 1 1 and to which the return electrode 4 of each pair of electrodes 3 and 4 belonging to group 1 1 ) or a single return electrode 4 (so that there is a single return electrode 4 common to all pairs of electrodes 3 and 4 belonging to group 11 and to which the delivery electrode 3 of each pair of electrodes belonging to group 1 1 is coupled to). In other words, in each pair of electrodes 3 and 4 belonging to group 1 1 , the delivery electrode 3 or the return electrode 4 coincide respectively with the delivery electrode 3 or with the return electrode 4 of each other pair of electrodes 3 and 4 belonging to group 11 so that, in each pair of electrodes 3 and 4 belonging to group 1 1 , the delivery electrode 3 or the return electrode 4 is in common with each other pair of electrodes 3 and 4 belonging to group 1 1 .

In addition to what has been said, the delivery electrode 3 and the return electrode 4 of each pair of electrodes 3 and 4 belonging to the group 1 1 lie at a mutual distance different from that at which the delivery electrode 3 and the return electrode 4 of each other pair of electrodes 3 and 4 belonging to group 11 .

In the variant of the device 1 shown in figure 3, the group 1 1 includes a number of pairs of electrodes equal, by way of example, to eight. Said eight pairs of electrodes preferably have the return electrode 4 in common. The group 1 1 therefore includes, by way of example, eight delivery electrodes 3 and a single return electrode 4 common to all eight pairs of electrodes 3 and 4 belonging to group 1 1 . In other words, the return electrode 4 of one of the eight pairs of electrodes 3 and 4 belonging to group 1 1 coincides with the return electrode 4 of each of the remaining seven pairs of electrodes belonging to group 1 1 . The eight delivery electrodes 3 belonging to the group 1 1 are preferably distributed around the single return electrode 4 so that the latter occupies an almost central position in the set of electrodes included in the group 1 1 . The eight segments 5 which respectively connect the eight supply electrodes sent 3 belonging to the group 11 to the single return electrode 4 belonging to the said group 1 1 are therefore distributed almost radially around the return electrode 4 belonging to the group 1 1 (corresponding to an end common to all the aforementioned eight segments 5 of the electrodes

3 and 4 belonging to group 11 ). Equivalent to what has been described above, the group 11 could comprise eight return electrodes 4 distributed around a single delivery electrode 3 common to all eight pairs of electrodes belonging to the group 1 1.

Similarly to what was said for group 1 1 , all the pairs of electrodes 3 and 4 belonging to the group 12 share a single delivery electrode 3 (so that there is a single delivery electrode 3 common to all the pairs of electrodes 3 and 4 belonging to the group 12 and to which the return electrode 4 of each pair of electrodes 3 and

4 belonging to the group 12 is coupled) or a single return electrode 4 (so that there is a single return electrode 4 common to all the pairs of electrodes 3 and 4 belonging to group 12 and to which the delivery electrode 3 of each pair of electrodes belonging to group 12 is coupled). In other words, in each pair of electrodes 3 and 4 belonging to group 12, the delivery electrode 3 or the return electrode 4 coincide respectively with the delivery electrode 3 or with the return electrode 4 of each other pair of electrodes 3 and 4 belonging to group 12 so that, in each pair of electrodes 3 and 4 belonging to group 12, the delivery electrode 3 or the return electrode 4 is in common with each other pair of electrodes 3 and 4 belonging to group 12.

In addition to what has been said, the delivery electrode 3 and the return electrode 4 of each pair of electrodes 3 and 4 belonging to the group 12 lie at a mutual distance different from that at which the delivery electrode 3 and the return electrode 4 of each other pair of electrodes 3 and 4 belonging to group 12. In the variant of the device 1 shown in figure 3, the group 12 includes a number of pairs of electrodes equal, by way of example, to eight. Said eight pairs of electrodes preferably have the return electrode 4 in common. The group 12 therefore includes, by way of example, eight delivery electrodes 3 and a single return electrode 4 common to all eight pairs of electrodes 3 and 4 belonging to group 12. In other words, the return electrode 4 of one of the eight pairs of electrodes 3 and 4 belonging to group 12 coincides with the return electrode 4 of each of the remaining seven pairs of electrodes belonging to group 12. The eight delivery electrodes

3 belonging to the group 12 are preferably distributed around the single return electrode 4 so that the latter occupies an almost central position in the set of electrodes included in the group 12. The eight segments 5 which respectively connect the eight supply electrodes sent 3 belonging to group 12 to the single return electrode 4 belonging to said group 12 are therefore distributed almost radially around the return electrode 4 belonging to group 12 (corresponding to an end common to all the aforementioned eight segments 5 of the electrodes 3 and

4 belonging to group 12). Equivalent to what has been described above, the group 12 could comprise eight return electrodes 4 distributed around a single delivery electrode 3 common to all eight pairs of electrodes belonging to the group 12. The delivery electrodes 3 of the group 12 are placed, at by way of example, along a spiral corresponding to the pole of which the return electrode 4 of group 12 is located.

As can be seen in figure 3, in each pair of electrodes 3 and 4 belonging to the group 1 1 , both the delivery electrode 3 and the return electrode 4 are not in common with any pair of electrodes 3 and 4 included in the group 12. In other words, groups 11 and 12 do not share any electrodes 3 or 4. In addition to that, the number of electrodes 3 and 4 included in group 1 1 coincides with the number of electrodes 3 and 4 included in group 12. The mutual distance at which the delivery electrode 3 and the return electrode 4 lie of each pair of electrodes belonging to the group 1 1 coincides with the mutual distance at which the delivery electrode 3 and the return electrode 4 lie of a pair of electrodes 3 and 4 belonging to group 12. In other words, groups 1 1 and 12 differ from each other due to the spatial distribution of the electrode pairs 3 and 4. As mentioned previously, the electrodes 3 and 4 of each pair are arranged on the wall 2 in such a way that, by tracing a segment 5 having as its ends the electrodes 3 and 4 of said pair, said segment 5 does not intersect any other segment 5 (i.e., no segment having as its ends the electrodes 3 and 4 of each other pair of electrodes) and no electrode 3 or 4 of each other pair of electrodes lying on said segment 5. This is confirmed not only within each of the groups 11 and 12 but also between a group 1 1 or 12 and the other group 12 or 1 1 , i.e., the electrodes

3 and 4 of each pair of one of the two groups 1 1 and 12 are arranged on the wall 2 in such a way that, by tracing a segment 5 having as ends the electrodes 3 and

4 of said pair, said segment 5 does not intersect any segment 5 having as ends electrodes 3 and 4 of each other pair of electrodes of said group 11 or 12, nor of each pair of the other group 12 or 1 1 , and no electrode 3 or 4 of each other pair of electrodes 3 and 4 of said group 1 1 or 12, nor of each pair of the other group 12 or 1 1 , lies on said segment 5.

In the variant of the device 1 shown in figure 3, for the return electrode 4 of each pair of electrodes 3 and 4 belonging to the group 1 1 , the unit 6, when the electrodes 3 and 4 (both of the group 11 and of the group 12) are in contact with the skin of a person in correspondence with the area of the skin being subjected to impedance measurement examination and the emitting components confer excitation signals in the delivery electrode 3 included in said pair of electrodes 3 and 4 of group 1 1 , it is preferably suitable for carry out an average between the frequency impedance spectrum generated by the acquisition components for said return electrode 4 and the frequency impedance spectrum generated by the acquisition components for the return electrode 4 of the pair of electrodes 3 and 4 belonging to group 12 and in which the electrodes 3 and 4 lie at the same mutual distance at which the electrodes 3 and 4 of said pair of electrodes 3 and 4 of the group 1 1 lie. The unit 6 is also preferably suitable for storing the aforementioned average in the memory 7.

For the return electrode 4 of each pair of electrodes 3 and 4 belonging to the group 1 1 , the unit 6, when the electrodes 3 and 4 (both of the group 1 1 and of the group 12) are in contact with the skin of a person in correspondence with the area of the skin subject to impedance measurement examination and the emitting components confer excitation signals in the delivery electrode 3 included in said pair of electrodes 3 and 4 of group 11 , it is preferably also suitable for comparing the frequency impedance spectrum generated by the components acquisition devices for said return electrode 4 and the frequency impedance spectrum generated by the acquisition components for the return electrode 4 of the pair of electrodes 3 and 4 belonging to the group 12 and in which the electrodes 3 and 4 lie at the same mutual distance at which lie the electrodes 3 and 4 of said pair of electrodes 3 and 4 belonging to group 1 1 . The unit 6 is also preferably suitable for estimating a degree of similarity between the frequency impedance spectrum generated by the acquisition components for said return electrode 4 and the frequency impedance spectrum generated by the acquisition components for the return electrode 4 of the pair of electrodes 3 and 4 belonging to the group 12 and in which the electrodes 3 and 4 lie at the same distance from each other as the electrodes 3 and 4 of said pair of electrodes 3 and 4 belonging to group 1 1 . The unit 6 is preferably also suitable for storing the aforementioned degree of similarity in the memory 7.

In light of what has been said, the memory 7, for the electrode 4 of each pair of electrodes 3 and 4 belonging to the group 1 1 (or equivalently 12), is suitable for containing the aforementioned average and the aforementioned degree of similarity calculated by the unit 6 for said electrode 4 as specified above.

Incidentally, since in group 1 1 (or equivalently in group 12) there is a single electrode 4 common to all pairs of electrodes 3 and 4 belonging to said group 1 1 , generate the frequency impedance spectrum for electrode 4 of each pair of electrodes 3 and 4 belonging to group 1 1 (or 12) means generating the frequency impedance spectra in correspondence with said single electrode 4 by sending to the latter excitation signals emitted in succession from all the electrodes 3 of the pairs of electrodes 3 and 4 belonging to group 1 1 (or 12).

When the device 1 is connected to the device 9 through the components 8, the unit 6 is preferably suitable for transmitting to the device 9 also the aforementioned averages and the aforementioned degrees of similarity stored in the memory 7.

Preferably, the unit 6, when the electrodes 3 and 4 (both of group 1 1 and of group 12) are in contact with the skin of a person in correspondence with the area of the skin being subjected to impedance measurement examination, are suitable for activating the emitting components and the acquisition components, during a first predefined time interval, so as to generate the impedance frequency spectra by acquiring excitation signals from the electrode 4 of each pair of electrodes 3 and 4 belonging to the group 1 1 and from the electrode 4 of each pair of electrodes 3 and 4 belonging to group 12. Unit 6 is also preferably suitable for estimating the degree of similarity between the frequency impedance spectrum generated for electrode 4 of each pair of electrodes 3 and 4 belonging to group 1 1 and the frequency impedance spectrum generated for the electrode 4 of the corresponding pair of electrodes 3 and 4 belonging to group 12 (as previously said, i.e., for the return electrode 4 of the pair of electrodes 3 and 4 belonging to group 12 and in which the electrodes 3 and 4 lie at the same distance from each other as the electrodes 3 and 4 of said pair of electrodes 3 and 4 belonging to the group 1 1 ). Unit 6 is also suitable for estimating a degree of agreement between groups 11 and 12 on the basis of the aforementioned degree of similarity between the frequency impedance spectrum generated for electrode 4 of each pair of electrodes 3 and 4 belonging to group 1 1 and the frequency impedance spectrum generated for the electrode 4 of the corresponding pair of electrodes 3 and 4 belonging to the group 12. The unit 6 is preferably also suitable for storing the aforementioned degree of agreement in the memory 7.

When the device 1 is connected to the device 9 through the components 8, the unit 6 is preferably suitable for transmitting to the device 9 also the aforementioned degree of agreement stored in the memory 7.

Incidentally, the calculation of the average between two impedance frequency spectra, the estimate of a degree of similarity between two impedance frequency spectra and the estimate of a degree of agreement between groups 1 1 and 12 on the basis of the degrees of similarity between the spectra frequency impedance measurements calculated for the return electrodes 4 of the two aforementioned groups 11 and 12, are substantially known operations for a technician expert in the sector. We therefore do not focus on providing further details.

Preferably, the unit 6 is suitable for communicating to a user of the device 1 , for example visually with the switching on of a warning light, whenever the aforementioned degree of agreement is estimated, whether said degree of agreement is higher or less than a first default limit value. If the degree of agreement is not greater than said limit value, this means that groups 1 1 and 12 are so in disagreement with each other that it is advisable to repeat the impedance test.

Figures 4 and 5 show, respectively, two other variants of device 1 which differ from the variant of device 1 shown in figure 3 due to the different spatial distribution of the pairs of electrodes 3 and 4. More precisely, both in the variant of device 1 shown in figure 4 that in the one shown in figure 5 also the delivery electrodes 3 of group 1 1 (i.e., in addition to those of group 12) are placed along a spiral corresponding to the pole of which the return electrode 4 of group 11 is placed. The variants of the device 1 shown in figures 4 and 5 differ from each other due to the different orientation of the electrode spirals 3 and 4.

Regardless of the presence or absence of the groups 1 1 and 12 (i.e., with reference to the device 1 or to one of its variants illustrated above), the unit 6 is preferably suitable for operating the emitting components and the acquiring components, during a second predefined interval of time, in such a way as to try to generate impedance spectra in frequency by acquiring excitation signals from the return electrode 4 of each pair of electrodes 3 and 4, and to communicate to a user of the device 1 , for example visually by switching on a warning light, if the number of electrode pairs 3 and 4 for which it was possible to generate the frequency impedance spectrum is greater or less than a second predefined limit value. If the number of pairs of electrodes 3 and 4 for which it was possible to generate the frequency impedance spectrum is not greater than said limit value, this means for example that the electrodes 3 and 4 in contact with the skin are so few that it is advisable to repeat the impedance test.

Again regardless of the presence or absence of groups 11 and 12, unit 6 is preferably suitable for estimating the tissue composition of a person's skin (in correspondence with the area of the skin subject to impedance analysis) starting from the impedance spectra stored in the memory 7 and to store the estimated tissue composition in the latter. Incidentally, how to estimate the tissue composition of a person's skin starting from impedance spectra is substantially known to a technician expert in the sector. We therefore do not focus on providing further details. When the device 1 is connected to the device 9 through the components 8, the unit 6 is preferably suitable for transmitting to the device 9 also the aforementioned tissue composition stored in the memory 7.

Figure 6 shows an example of implementation of the previously mentioned emitting components of the device 1 (or one of its variants described above). More precisely, the delivery of excitation signals into the electrode 3 of (at least) one of the pairs of electrodes 3 and 4 can preferably take place by means of an oscillator 13 suitable for emitting periodic signals, preferably of the sinusoidal type. The unit 6 is preferably connected to the oscillator 13 (as shown in figure 12) and is preferably suitable for regulating the frequency at which the oscillator 13 emits the aforementioned periodic signals. The oscillator 13 is connected to a variable gain amplifier 14 for feeding into the latter the aforementioned periodic signals emitted by the oscillator 13. The unit 6 is preferably also connected to the amplifier 14 (as shown in figure 12) and it is preferably suitable for regulating the gain of the amplifier 14 and consequently the amplitude of the aforementioned periodic signals as amplified by the amplifier 14 (i.e., at the output of the latter). The amplifier 14 is connected to the aforementioned electrode 3 for the delivery to the latter of the amplified periodic signals (therefore corresponding to the excitation signals emitted by the emitting components).

Figure 7 shows an example of implementation of the previously mentioned emitting components of the device 1 (or one of its variants described above) alternative to the example shown in figure 6. More precisely, according to what is shown in figure 7, the provision of control signals excitation in the electrode 3 of (at least) one of the pairs of electrodes 3 and 4 can preferably take place through a synthesizer 15 suitable for simultaneously emitting multiple periodic signals, preferably of the sinusoidal type, at frequencies contained in a stored table in a second memory 16. The unit 6 is preferably connected to the memory 16 (as shown in figure 12) and is suitable for inserting frequency values into the table contained in said memory 16. The synthesizer 15 is connected to a variable gain amplifier 17 for the transfer into the latter of the aforementioned multiple periodic signals emitted by the synthesizer 15. The unit 6 is preferably also connected to the amplifier 17 (as shown in figure 12) and is preferably suitable for regulating the gain of the amplifier 17 and consequently the amplitude of the aforementioned multiple period signals as amplified by the amplifier 17 (i.e., at the output of the latter). The amplifier 17 is connected to the aforementioned electrode 3 for the delivery into the latter of the multiple amplified period signals (therefore corresponding to the excitation signals emitted by the emitting components).

If, as shown in figure 7, the synthesizer 15 is digital, the latter, instead of being connected directly to the amplifier 17, is connected to an analogue digital converter 18 for the transfer thereof of the aforementioned multiple periodic signals. It is the converter 18 that is connected to the amplifier 17 for the transfer thereof of the aforementioned multiple periodic signals made analogue by the converter 18. In other words, if the synthesizer 15 is digital, the latter is connected to the amplifier 17 via of the converter 18.

Figure 8 shows a line deselector 19 preferably included in the device 1 in the event that the latter includes a first set of electrodes 3 that do not coincide with each other (i.e., in the event that there are at least two pairs of electrodes 3 and 4 that do not share the electrode 3). The input 20 of the deselector 19 is connected to the output of the amplifier 14 or 17 so that the latter is suitable for imparting its excitation signals into the deselector 19. Each of the outputs 21 of the deselector 19 is connected to one of the electrodes 3 of the the aforementioned first assembly in such a way that each output 21 is connected to one and only one of the electrodes 3 belonging to the aforementioned first assembly. The deselector 19 is suitable for connecting the input 20 to each of the outputs 21 and to no more than one output 21 at a time in such a way that the excitation signals can be transferred from the amplifier 14 or 17 into the electrode 3 connected to the output 21 connected to input 20. In light of what has been said, the device 1 , instead of comprising an amplifier 14 or 17 (together with the other elements described above for the purpose of emitting excitation signals) for each electrode 3 belonging to the aforementioned first together, preferably comprises a single amplifier 14 or 17 and the deselector 19 with its input connected to the output of the amplifier 14 or 17 and with its outputs 21 respectively connected to the electrodes 3 of the aforementioned first assembly. The amplifier 14 or 17 is therefore suitable for imparting excitation signals into each of the electrodes 3 of the aforementioned first assembly through the deselector 19. The unit 6 is preferably connected to the deselector 19 (as shown in figure 12) and is preferably suitable for selecting which output 21 the input 20 is connected to and consequently for selecting into which electrode 3 among those belonging to the aforementioned first set the excitation signals from the amplifier 14 or 17 can be delivered via the deselector 19.

Figure 9 shows an example of embodiment of the previously mentioned acquisition components of the device 1 in the case in which the latter includes emitter components according to the embodiment example shown in figure 6. More precisely, the acquisition from the electrode 4 of (at least ) one of the pairs of electrodes 3 and 4 of excitation signals received from said electrode 4 when the electrodes 3 and 4 of the device 1 are in contact with the skin of a person in correspondence with an area of the skin (object of impedance measurement examination) and after said excitation signals have propagated in the skin of said person in correspondence with said area starting from the electrode 3 included in said pair of electrodes following a delivery by the amplifier 14 into said electrode 3 of periodic signals following an emission of the same by the oscillator 13 can preferably take place through a transconductance operational amplifier 22 connected to said electrode 4. The amplifier 22 is connected to a further variable gain amplifier 23 for a transfer into the latter of the excitation signals acquired by the amplifier 22, as if amplified by it. The unit 6 is preferably connected to the amplifier 23 (as shown in figure 12) and is preferably suitable for regulating the gain of the amplifier 23 and consequently the amplitude of the excitation signals as amplified by the amplifier 23 (i.e., at the output of the latter). The amplifier 23 is connected to a first filter 24 of the "low pass" type for delivery thereof of the excitation signals as amplified by the amplifier 23. The filter 24 is connected to a quadrature demodulator 25 for delivery in this last of the excitation signals as filtered by the filter 24. The demodulator 25 is connected to the oscillator 13 and is suitable for quadrature demodulating the excitation signals as filtered by the filter 24 using as a reference frequency the frequency at which the oscillator 13 emits periodic signals. The demodulator 25 is furthermore connected to a second filter 26 and a third filter 27, both of the "low-pass" type, for providing them respectively with the real component and the imaginary component of the excitation signals as filtered by the filter 24. The filter 26 is connected to a first analog-digital converter 28 for feeding into it the real component of the excitation signals as filtered by the filter 26. Similarly, the filter 27 is connected to a second analog-digital converter 29 for feeding into it the imaginary component of the excitation signals as filtered by the filter 27. The converters 28 and 29 are connected to the memory 7 and are suitable for transferring into the latter the real and imaginary components as respectively sampled by the converters 28 and 29, so as to generate an impedance spectrum in frequency of the excitation signals when acquired by said electrode 4 by the amplifier 22. Incidentally, the obtaining of a frequency impedance spectrum starting from the real and imaginary components as respectively sampled by the converters 28 and 29 is substantially known to a expert technician in the sector. We therefore do not focus on providing further details.

Figure 10 shows an example of embodiment of the previously mentioned acquisition components of the device 1 (alternative to the example shown in figure 9) in the case in which the device 1 includes emitter components according to the embodiment example shown in figure 7. More precisely, the acquisition from the electrode 4 of (at least) one of the pairs of electrodes 3 and 4 of excitation signals received from said electrode 4 when the electrodes 3 and 4 of the device 1 are in contact with the skin of a person at a area of the skin (subject of impedance measurement examination) and after said excitation signals have propagated in the skin of said person in correspondence with said area starting from electrode 3 included in said pair of electrodes following a contribution by the amplifier 17 in said electrode 3 of multiple periodic signals following their emission by the synthesizer 15, can preferably take place through a transconductance operational amplifier 30 connected to said electrode 4. The amplifier 30 is connected to a further variable gain amplifier 31 for feeding into the latter the excitation signals acquired by the amplifier 30, as amplified by it. The unit 6 is preferably connected to the amplifier 31 (as shown in figure 12) and is preferably suitable for regulating the gain of the amplifier 31 and consequently the amplitude of the excitation signals as amplified by the amplifier 31 (i.e., at the output of the latter). The amplifier 31 is connected to a filter 32 of the "low pass" type for the delivery thereof of the excitation signals as amplified by the amplifier 31 . The filter 32 is connected to an analogue-digital converter 33 for the delivery thereof of the signals of excitation as filtered by the filter 32. The converter 33 is connected to a module 34 for calculating the discrete Fourier transform for the transfer thereof of the excitation signals as sampled by the converter 33. The module 34 is suitable for generating and conveying in the memory 7, to which it is connected, a frequency impedance spectrum of the excitation signals when acquired by said electrode 4 by the amplifier 30. Incidentally, the obtaining of a frequency impedance spectrum starting from the excitation signals as sampled by the converter 33 is substantially known to a person skilled in the art. We therefore do not focus on providing further details.

Figure 11 shows a line selector 35 preferably included in the device 1 in the case in which the latter includes a second set of electrodes 4 not coinciding with each other (i.e., there are at least two pairs of electrodes 3 and 4 not sharing the electrode 4 ). Each of the inputs 36 of the selector 35 is connected to one of the electrodes 4 of the aforementioned second assembly in such a way that each input 36 is connected to one and only one of the electrodes 4 belonging to the aforementioned second assembly. The output 37 of the selector 35 is connected to the input of the amplifier 22 or 30 so that the latter is suitable for acquiring the excitation signals in the selector 35. The latter is suitable for connecting the output 37 to each of the inputs 36 and to no more than one input 36 at a time so that the excitation signals can be acquired by the amplifier 22 or 30 from the electrode 4 connected to the input 36 connected to the output 37. In light of what has been said, the device 1 , instead of comprising an amplifier 22 or 30 (together with the other elements described above for the purposes of acquiring the excitation signals) for each electrode 4 belonging to the aforementioned second assembly, it preferably comprises a single amplifier 22 or 30 and the selector 35 with its own inputs 36 respectively connected to the electrodes 4 of the aforementioned second assembly and its output 37 at the input of the amplifier 22 or 33. The amplifier 22 or 30 is therefore suitable for acquiring the excitation signals from each of the electrodes 4 of the aforementioned second assembly for via the selector 35. The unit 6 is preferably connected to the selector 35 (as shown in figure 12) and is preferably suitable for selecting which input 36 the output 37 is connected to and consequently for selecting from which electrode 4 among those belonging to the aforementioned second set the excitation signals from the amplifier 22 or 30 can be acquired via the selector 35.

Figure 12 schematically shows the connections between unit 6 and some of the components of device 1 . More precisely, unit 6 is connected to the following com- ponents, if present, of device 1 : components 8 (for connecting device 1 to the device 9 via electromagnetic radio frequency waves), to the memory 7, to the oscillator 13, to the amplifier 14 or 17, to the memory 16, to the deselector 19, to the amplifier 23 or 31 and to the selector 35.

On the basis of the description provided for a preferred embodiment, it is obvious that some changes can be introduced by those skilled in the art without thereby departing from the scope of the invention as defined by the following claims.

Claims

C L A I M S

1. Device (1 ) for conducting an impedance measurement of a person's skin, said device (1 ) comprising:

• a supporting structure at which said device (1 ):

- can be grasped by a person and

- when grasped by a person, can be brought into contact with the skin of said person in an area of said skin to perform an impedance test in said area, said device (1 ) being characterized in that it also comprises:

• a plurality of pairs of electrodes (3, 4), each pair of electrodes (3, 4) of said plurality including a delivery electrode

(3) and a return electrode (4), in each pair of electrodes (3, 4) of said plurality, said delivery electrode (3) or said return electrode (4) coinciding respectively with said delivery electrode (3) or with said return electrode (4) of at least another pair of electrodes (3, 4) of said plurality so that, in each pair of electrodes (3, 4) of said plurality, said delivery electrode (3) or said return electrode (4) is in common with at least another pair of electrodes (3, 4) of said plurality, said electrodes (3, 4) of each pair of said plurality being arranged in such a way that, tracing a segment (5) having as ends the two electrodes (3, 4) of said pair:

- said segment (5) does not intersect any segment (5) having as ends the two electrodes (3, 4) of each other pair of said plurality and

- no electrode (3, 4) of each other pair of said plurality lies on said segment (5), said delivery electrode (3) and said return electrode (4) of at least one pair of electrodes (3, 4) of said plurality lying at a mutual distance different from that at which said delivery electrode (3) and said electrode lie return (4) of at least one other pair of electrodes (3, 4) of said plurality, said device (1 ) being brought into contact with the skin of said person in correspondence with said area in such a way that said electrodes (3, 4) of each pair of said plurality are in contact with the skin of said person in correspondence with said area;

• generating means (13, 14, 15, 16, 17, 18) suitable for emitting excitation signals at a plurality of frequencies and at a plurality of amplitudes, said generating means (13, 14, 15, 16, 17, 18)

- being connected to said delivery electrode (3) of each pair of said plurality and

- being suitable for imparting said excitation signals to said delivery electrode (3) of each pair of said plurality so that, when said electrodes (3, 4) of each pair of said plurality are in contact with the skin of said person in correspondence with said area and said generating means (13, 14, 15, 16, 17, 18) emit said excitation by conferring the latter in said delivery electrode (3) of a pair of electrodes (3, 4) of said plurality, said excitation signals conferred in said delivery electrode (3) are propagated through the skin of said person in correspondence with said area reaching said return electrode (4) belonging to said pair of electrodes (3, 4), or said return electrodes (4) belonging to said pairs of electrodes (3, 4) if more than one, to which said delivery electrode (3) belongs;

• detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) suitable for acquiring said excitation signals, said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34)

- being connected to said return electrode (4) of each pair of said plurality, and

- being suitable for acquiring said excitation signals possibly received by said return electrode (4) of each pair of said plurality, and for generating an impedance spectrum across frequencies of said excitation signals possibly acquired by said return electrode (4), so that, when the electrodes (3, 4) of said plurality are in contact with the skin of said person in correspondence with said area and said generating means (13, 14, 15, 16, 17, 18) emit said excitation signals, conferring these last in said delivery electrode (3) of a pair of electrodes (3, 4) of said plurality, said excitation signals are acquired by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) after having propagated through the skin of said person in correspondence with said area starting from said delivery electrode (3) and having reached said return electrode (4) belonging to said pair of electrodes (3, 4), or to one of said pairs of electrodes (3, 4) if more than one , to which said delivery electrode belongs (3) and said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) generate said impedance spectrum across frequencies of said excitation signals acquired by said return electrode (4);

• a first memory (7) suitable for containing said frequency impedance spectrum generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) for said return electrode (4) of each pair of said plurality, or a series of said impedance versus frequency spectra generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32 , 33, 34) for said return electrode (4) of each pair of said plurality;

• control means (6) of said generating means (13, 14, 15, 16, 17, 18) and of said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34), said control means (6) being suitable for adjusting the frequencies and amplitudes at which said generating means (13, 14, 15, 16, 17, 18) emit said excitation signals, said generating means (13, 14, 15, 16, 17, 18) being controlled by said control means (6) in such a way as to confer said excitation signals emitted by said generating means (13, 14, 15, 16 , 17, 18) to no more than one of said delivery electrodes (3) at a time, so that at any instant of time said excitation signals can be conferred by said generating means (13, 14, 15, 16, 17, 18) to one and only one of said delivery electrodes (3), said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) being controlled by said control means (6) in such a way as to acquire said excita- tion signals emitted by said generating means (13, 14, 15, 16, 17, 18) and transferred to one of said delivery electrodes (3)

- by no more than one of said return electrodes (4) at a time, so that at any instant of time said excitation signals can be acquired by one and only one of said return electrodes (4) and

- from said return electrode (4) of said pair, if only one, or of one of said pairs, if more than one, of said plurality which includes said delivery electrode (3) in which said generating means (13, 14, 15, 16, 17, 18) have conferred said excitation signals, said control means (6) being suitable for memorizing in said first memory (7) one or more said impedance versus frequency spectra generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30 , 31 , 32, 33, 34) for said return electrode (4) of each pair of said plurality;

• connecting means (8) suitable for establishing a connection between said device (1 ) and an electronic device (9) for the transmission of data between said control means (6) and said device (9), when said device (1 ) is connected to said appliance (9) by means of said connecting means (8), said control means (6) being suitable for

- transmitting to said apparatus (9) said impedance versus frequency spectra stored in said first memory (7) and for

- receiving from said apparatus (9) activation commands of said generating means (13, 14, 15, 16, 17, 18) and of said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34).

2. Device (1 ) according to claim 1 , characterized in that said supporting structure comprises a wall (2) at which said device (1 ), when gripped by said person, can be brought into contact with the skin of said person in said zone, said electrodes (3, 4) being in correspondence with at least a portion of said wall (2).

3. Device (1 ) according to claim 2, characterized in that said wall (2) comprises at least one concavity and/or at least one convexity at least in corre- spondence with said portion thereof.

4. Device (1 ) according to one of claims 2 or 3, characterized in that each of said electrodes (3, 4) is at least partially convex in such a way that, when said device (1 ), at said wall (2), is pressed against the skin of said person in correspondence with said area, said electrodes (3, 4) push the skin inwards with respect to the position assumed by the skin in the absence of pressure.

5. Device (1 ) according to one of the preceding claims, characterized in that said generating means (13, 14, 15, 16, 17, 18) comprise:

• an oscillator (13) suitable for emitting periodic signals preferably of the sinusoidal type, said control means (6) being suitable for adjusting the frequency at which said oscillator (13) emits said periodic signals;

• a variable gain amplifier (14), said oscillator (13) being connected to said amplifier (14) so as to be suitable for imparting said periodic signals into said amplifier (14), said control means (6) being suitable for adjusting the gain of said amplifier (14) and consequently the amplitude of said periodic signals as amplified by said amplifier (14), said amplifier (14) being suitable for imparting said amplified periodic signals into said delivery electrode (3) of at least one pair of electrodes (3, 4) of said plurality, said amplified periodic signals therefore corresponding to said excitation signals which can be emitted by said generating means (13, 14, 15, 16, 17, 18).

6. Device (1 ) according to one of claims 1 to 4, characterized in that said generating means (13, 14, 15, 16, 17, 18) comprise:

• a second memory (16) suitable for containing at least one table of frequencies, said control means (6) being suitable for entering frequency values in said table;

• a synthesizer (15) suitable for simultaneously emitting multiple periodic signals at frequencies contained in said table;

• if said synthesizer (15) is of the digital type, a digital to analog converter (18), said synthesizer (15) being connected to said converter (18) so as to be suitable for imparting said multiple periodic signals into said converter (18);

• a variable gain amplifier (17), said synthesizer (15), if of the analog type, or said converter (18), if present, being connected to said amplifier (17) so as to be suitable for imparting said multiple periodic signals into said amplifier (17), said control means (6) being suitable for adjusting the gain of said amplifier (17) and consequently the amplitude of said multiple periodic signals as amplified by said amplifier (17), said amplifier (17) being suitable for imparting said multiple amplified periodic signals into said delivery electrode (3) of at least one pair of electrodes (3, 4) of said plurality, said amplified periodic signals therefore corresponding to said excitation signals which can be emitted by said generating means (13, 14, 15, 16, 17, 18).

7. Device (1 ) according to claim 5 or 6, characterized in that, if in said plurality of pairs of electrodes (3, 4) there is a first set of delivery electrodes (3) which do not coincide with each other, said device (1 ) includes a line deselector (19), said amplifier (14, 17) being connected to the input (20) of said deselector (19) so as to be suitable for imparting said energizing signals into said deselector (19), each of said delivery electrodes (3) belonging to said first set being connected to an output (21 ) of said deselector (19) in such a way that each output of said deselector (19) is connected to one and only one of said delivery electrodes (3) belonging to said first set, said deselector (19) being suitable for connecting its input (20) to each of its outputs (21 ) and to no more than one output (21 ) at a time in such a way that said excitation signals are transferable from said amplifier (14, 17) in said delivery electrode (3) connected to the output of said deselector (19) connected to the input (20) of the latter, said amplifier (14, 17) being therefore suitable for imparting said excitation signals to each of said delivery electrodes (3) belonging to said first set by means of said deselector (19), said control means (6) being suitable for selecting to which output (21 ) of said deselector (19) the input (20) of the same is connected and consequently being suitable for selecting in which of said delivery electrodes (3) belonging said excitation signals can be conferred to said first set by said amplifier (14, 17) by means of said deselector (19).

8. Device (1 ) according to claim 5 or according to claim 7 when dependent on claim 5, characterized in that said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) include:

• a transconductance operational amplifier (22), said transconductance amplifier (22) being suitable for acquiring from said return electrode (4) of at least one pair of electrodes (3, 4) of said plurality said excitation signals received from said return electrode (4) when the electrodes (3, 4) of said plurality are in contact with the skin of said person in correspondence with said zone and after said excitation signals have propagated through the skin of said person in correspondence with said zone starting from said delivery electrode (3) included in said pair of electrodes (3, 4) following a contribution by said amplifier (14) included in said generating means (13, 14, 15, 16, 17, 18) in said delivery electrode (3) of said periodic signals following their emission by said oscillator (13);

• a further variable gain amplifier (23), said transconductance amplifier (22) being connected to said further amplifier (23) so as to be suitable for imparting to said further amplifier (23) said excitation signals as amplified by said transconductance amplifier (22), said control means (6) being suitable for adjusting the gain of said further amplifier (23) and consequently the amplitude of said excitation signals as further amplified by said further amplifier (23);

• a first filter (24) of the “low pass” type said further amplifier (23) being connected to said first filter (24) so as to be suitable for imparting to said first filter (24) said further amplified excitation signals;

• a quadrature demodulator (25), said first filter (24) being connected to said demodulator (25) so as to be suitable for imparting into said demodulator (25) said excitation signals as filtered by said first filter (24), said demodulator (25) being connected to said oscillator (13) and being suitable for demodulating in quadrature said excitation signals as filtered by said first filter (24) using as reference frequency the frequency at which said oscillator (13) emits said signals periodicals;

• a second filter (26) of the “low pass” type, the real output of said demodulator (25) being connected to said second filter (26) so that said demodulator (25) is suitable for imparting into said second filter (26) the real component of said excitation signals as filtered by said first filter (24);

• a third filter (27) of the “low pass” type, the imaginary output of said demodulator (25) being connected to said third filter (27) so that said demodulator (25) is suitable for imparting into said third filter (27) the imaginary component of said excitation signals as filtered by said first filter (24);

• a first analog to digital converter (28), said second filter (26) being connected to said first analog-to-digital converter (28) so as to be suitable for imparting into said first analog-to-digital converter (28) the real component of said excitation signals as filtered by said second filter (26);

• a second analog to digital converter (29), said third filter (27) being connected to said second analog-to-digital converter (29) so as to be suitable for imparting into said second analog-to-digital converter (29) the imaginary component of said excitation signals as filtered by said third filter (27), said first and second analog-to-digital converters (28, 29) being connected to said first memory (7) and being suitable for transferring into the latter said real and imaginary components as sampled by said first and second analog-to- digital converters (28, 29) , so as to generate an impedance spectrum across frequencies of said excitation signals when acquired by said return electrode (4) by said transconductance amplifier (22).

9. Device (1 ) according to claim 6 or according to claim 7 when depending on claim 6, characterized in that said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) include:

• a transconductance operational amplifier (30), said transconductance amplifier (30) being suitable for acquiring from said return electrode (4) of at least one pair of electrodes (3, 4) of said plurality said excitation signals received from said return electrode (4) when the electrodes (3, 4) of said plurality are in contact with the skin of said person in correspondence with said zone and after said excitation signals have propagated through the skin of said person in correspondence with said zone starting from said delivery electrode (3) included in said pair of electrodes (3, 4) following a contribution by said amplifier (17) included in said generating means (13, 14, 15, 16, 17, 18) in said delivery electrode (3) of said multiple periodic signals following an emission thereof by said synthesizer (15);

• an additional variable gain amplifier (31 ), said transconductance amplifier (30) being connected to said further amplifier (31 ) so as to be suitable for imparting to said further amplifier (31 ) said excitation signals as amplified by said transconductance amplifier (30), said control means (6) being suitable for adjusting the gain of said further amplifier (31 ) and consequently the amplitude of said excitation signals as further amplified by said further amplifier (31 );

• a “low pass” type filter (32), said further amplifier (31 ) being connected to said filter (32) so as to be suitable for imparting to said filter (32) said further amplified excitation signals;

• an analog to digital converter (33), said filter (32) being connected to said analog-to-digital converter (33) so as to be suitable for imparting into said analog-to-digital converter (33) said excitation signals as filtered by said filter (32);

• a calculation module (34) of the discrete Fourier transform, said analog-to-digital converter (33) being connected to said calculation module (34) so as to be suitable for imparting into said calculation module (34) said excitation signals as sampled by said analog-to-digital converter (33), said calculation module (34) being suitable for generating a frequency impedance spectrum of said excitation signals acquired by said return electrode (4) by said transconductance amplifier (30), said calculation module (34) being connected to said first memory (7) and being suitable for transferring into said first memory (7) said frequency impedance spectrum of said excitation signals when acquired by said return electrode (4) by of said transconductance amplifier (30).

10. Device (1 ) according to claim 8 or 9, characterized in that, if in said plurality of pairs of electrodes there is a second set of return electrodes (4) which do not coincide with each other, said device comprises a line selector (35), each of said return electrodes (4) belonging to said second set being connected to an input (36) of said selector (35) in such a way that each input (36) of said selector (35) is connected to one and one only of said return electrodes (4) belonging to said second set, said transconductance amplifier (22, 30) being connected to the output (37) of said selector (35) so as to be suitable for acquiring said excitation signals from said selector (35), said selector (35) being suitable for connecting its output (37) to each of its inputs (36) and to no more than one input (36) at a time in such a way that said excitation signals can be acquired by said amplifier transconductance (22, 30) from said return electrode (4) connected to the input (36) of said selector (35) connected to the output (37) of the latter, said transconductance amplifier (22, 30) being therefore suitable for acquiring said excitation signals from each of said return electrodes (4) belonging to said second set by means of said selector (35), said control means (6) being suitable for selecting which input (36) of said selector (35) the output (37) of the same is connected to and consequently being suitable for selecting from which of said return electrodes (4) belonging said excitation signals can be acquired by said second set from said transconductance amplifier (22, 30) by means of said selector (35).

1 1 . Device (1 ) according to one of the preceding claims, characterized in that, in said plurality of pairs of electrodes there is a first group (1 1 ) of pairs of electrodes (3, 4) of said plurality comprising multiple pairs of electrodes (3, 4) of said plurality, all said pairs of electrodes (3, 4) of said plurality belonging to said first group (1 1 ) sharing:

• said delivery electrode (3), so that there is a single delivery electrode (3) common to all the pairs of electrodes (3, 4) belonging to said first group (11 ) and to which said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (1 1 ) or

• said return electrode (4), so that there is a single return electrode (4) common to all the pairs of electrodes (3, 4) belonging to said first group (1 1 ) and to which said delivery electrode (3) of each pair of electrodes (3, 4) belonging to said first group (11 ), said delivery electrode (3) and said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (1 1 ) lying at a mutual distance different from that at which said delivery electrode (3) and said return electrode (4) of each other pair of electrodes (3, 4) belonging to said first group (11 ), in said plurality of pairs of electrodes (3, 4) there being at least a second group of pairs of electrodes (3, 4) of said plurality comprising multiple pairs of electrodes (3, 4) of said plurality, all said pairs of electrodes (3, 4) of said plurality belonging to said second group sharing:

• said delivery electrode (3), so that there is a single delivery electrode (3) common to all the pairs of electrodes (3, 4) belonging to said second group (12) and to which said return electrode (4) of each pair of electrodes (3, 4) belonging to said second group (12) or said return electrode (4), so that there is a single return electrode (4) common to all the pairs of electrodes (3, 4) belonging to said second group (12) and to which said delivery electrode (3) of each pair of electrodes (3, 4) belonging to said second group (12), said delivery electrode (3) and said return electrode (4) of each pair of electrodes (3, 4) belonging to said second group (12) lying at a mutual distance different from that at which said delivery electrode (3) lies and said return electrode (4) of each other pair of electrodes (3, 4) belonging to said second group (12), in each pair of electrodes (3, 4) belonging to said first group (11 ), both said delivery electrode (3) and said return electrode (4) being not in common with any pair of electrodes (3, 4) belonging to said second group (12), the number of said electrodes (3, 4) included in said first group (11 ) coinciding with the number of said electrodes (3, 4) included in said second group (12), the mutual distance at which said delivery electrode (3) and said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (11 ) lie, coinciding with the mutual distance at which said return electrode lie delivery (3) and said return electrode (4) of a pair of electrodes (3, 4) belonging to said second group (12).

12. Device (1 ) according to claim 11 , characterized in that, for said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (11 ), said control means (6), when the electrodes (3, 4) of said plurality are in contact with the skin of said person in correspondence with said area and said generating means (13, 14, 15, 16, 17, 18) confer said excitation signals in said delivery electrode (3) included in said pair, are suitable for

• averaging between

- said frequency impedance spectrum generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) for said return electrode (4)23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) per detto elettrodo di ritor- no (4) and

- said frequency impedance spectrum generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) for the return electrode (4) of the pair of electrodes (3, 4) belonging to said second group (12) and in which said delivery electrode (3) and said return electrode (4) lie at the same mutual distance at which said delivery electrode (3) and said return electrode (4) of said pair belonging to said first group (11 ),

• storing said average in said first memory (7),

• comparing

- said frequency impedance spectrum generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) for said return electrode (4) and

• estimating a degree of similarity between

- said frequency impedance spectrum generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) for the return electrode (4) of the pair of electrodes (3, 4) belonging to said second group (12) and in which said delivery electrode (3) and said return electrode (4) lie at the same mutual distance at which said delivery electrode (3) and said return electrode (4) of said pair belonging to said first group (11 ) and

• storing said degree of similarity in said first memory (7), said first memory (7), for said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (11 ), being therefore suitable also to contain: • said average between

- said frequency impedance spectrum generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) for the return electrode (4) of the pair of electrodes (3, 4) belonging to said second group (12) and in which said delivery electrode (3) and said return electrode (4) lie at the same mutual distance at which said delivery electrode (3) and said return electrode (4) of said pair belonging to said first group (11 );

• said degree of similarity between

- said frequency impedance spectrum generated by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) for the return electrode (4) of the pair of electrodes (3, 4) belonging to said second group (12) and in which said delivery electrode (3) and said return electrode (4) lie at the same mutual distance at which said delivery electrode (3) and said return electrode (4) of said pair belonging to said first group (11 ), when said device (1 ) is connected to said apparatus (9) by means of said connecting means (8), said control means (6) being suitable for transmitting to said apparatus (9) said averages and said degrees of similarity stored in said first memory (7).

13. Device (1 ) according to claim 12, characterized in that said control means (6), when the electrodes (3, 4) of said plurality are in contact with the skin of a person in correspondence with said area, are also suitable for:

• actuating said generating means (13, 14, 15, 16, 17, 18) and said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34), during a first predefined time interval, so as to generate said impedance versus frequency spectra by acquiring excitation signals from said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (11 ) and from said return electrode (4) of each pair of electrodes (3, 4) belonging to said second group (12),

• estimating said degree of similarity between said frequency impedance spectrum generated for said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (11 ) and said frequency impedance spectrum generated for said return electrode return (4) of the corresponding pair of electrodes (3, 4) belonging to said second group (12),

• estimating a degree of agreement between said two groups (11 , 12) of pairs of electrodes (3, 4) on the basis of said degree of similarity between said frequency impedance spectrum generated for said return electrode (4) of each pair of electrodes (3, 4) belonging to said first group (11 ) and said frequency impedance spectrum generated for said return electrode (4) of the corresponding pair of electrodes (3, 4) belonging to said second group (12) and

• storing said degree of chord in said first memory (7), said first memory (7) being therefore suitable to also contain said degree of agreement, when said device (1 ) is connected to said apparatus (9) by means of said connecting means (8), said control means (6) being suitable for transmitting to said apparatus (9) said degree of tuning memorized in said first memory (7).

14. Device (1 ) according to claim 13, characterized in that said control means (6) are also suitable for communicating to a user of said device (1 ), whenever said degree of agreement is estimated, if said degree of agreement is greater or less than a first predefined limit value.

15. Device (1 ) according to one of the preceding claims, characterized in that said control means (6) are also suitable for

• actuating said generating means (13, 14, 15, 16, 17, 18) and said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34), during a second predefined time interval, in such a way as to try to generate impedance versus frequency spectra by acquiring excitation signals from said return elec- trode (4) of each pair of electrodes (3, 4) of said plurality and for

• communicating to a user of said device (1 ) if the number of pairs of electrodes (3, 4) of said plurality for which it was possible to generate said impedance spectrum across frequencies is higher or not higher than a second predefined limit value.

16. Device (1 ) according to one of the preceding claims, characterized in that said control means (6) are also suitable for

• estimating the tissue composition of the skin in said area starting from said impedance versus frequency spectra stored in said first memory (7) and for

• storing said tissue composition in said first memory (7), said first memory (7) being therefore suitable to also contain said tissue composition, when said device (1 ) is connected to said apparatus by means of said connecting means (8), said control means (6) being suitable for transmitting to said apparatus (9) said tissue composition stored in said first memory (7).

17. Array of electrode pairs (3, 4), each pair of electrodes (3, 4) of said array including a delivery electrode (3) and a return electrode (4), said array of pairs of electrodes (3, 4) being characterized in that in each pair of electrodes (3, 4) of said array, said delivery electrode (3) or said return electrode (4) coincides respectively with said electrode delivery electrode (3) or with said return electrode (4) of at least one other pair of electrodes (3, 4) of said matrix so that, in each pair of electrodes (3, 4) of said matrix, said delivery electrode (3) or said return electrode (4) is in common with at least one other pair of electrodes (3, 4) of said array, said electrodes (3, 4) of each pair of said matrix being arranged in such a way that, tracing a segment (5) having as ends the two electrodes (3, 4) of said pair:

• said segment (5) does not intersect any segment (5) having as ends the two electrodes (3, 4) of each other pair of said matrix and • no electrode (3, 4) of each other pair of said matrix lies on said segment (5), said delivery electrode (3) and said return electrode (4) of at least one pair of electrodes (3, 4) of said matrix lying at a mutual distance different from that at which said delivery electrode (3) and said electrode lie return (4) of at least one other pair of electrodes (3, 4) of said matrix, said matrix being includeable in a device (1 ) for conducting an impedance measurement test of a person's skin, said device (1 ) comprising:

• generating means (13, 14, 15, 16, 17, 18) suitable for emitting excitation signals at a plurality of frequencies and at a plurality of amplitudes;

• detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) suitable for acquiring said excitation signals, said matrix being includeable in said device (1 ) in such a way that:

• said electrodes (3, 4) of each pair of said matrix can be brought into contact with the skin of said person in correspondence with said area;

• said generating means (13, 14, 15, 16, 17, 18)

- are connected to said delivery electrode (3) of each pair of said matrix and

- are suitable for imparting said excitation signals to said delivery electrode (3) of each pair of said matrix so that, when said electrodes (3, 4) of each pair of said matrix are in contact with the skin of said person in correspondence with said area and said generating means (13, 14, 15, 16, 17, 18) emit said excitation by imparting the latter into said delivery electrode (3) of a pair of electrodes (3, 4) of said matrix, said excitation signals conferred in said delivery electrode (3) are propagated through the skin of said person in correspondence with said area reaching said return electrode (4) belonging to said pair of electrodes (3, 4), or said return electrodes (4) belonging to said pairs of electrodes (3, 4) if more than one, to which said delivery electrode (3) belongs);

• said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34)

- are connected to said return electrode (4) of each pair of said matrix rice and

- are suitable for acquiring said excitation signals possibly received by said return electrode (4) of each pair of said matrix, and for generating an impedance spectrum across frequencies of said excitation signals possibly acquired by said return electrode (4) so that, when said electrodes (3, 4) of each pair of said matrix are in contact with the skin of said person in correspondence with said area and said generating means (13, 14, 15, 16, 17, 18) emit said excitation by imparting the latter into said delivery electrode (3) of a pair of electrodes (3, 4) of said matrix, said excitation signals are acquired by said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) after having propagated through the skin of said person in correspondence with said area starting from said delivery electrode (3) and having reached said return electrode (4) belonging to said pair of electrodes (3, 4), or to one of said pairs of electrodes (3, 4) if more than one , to which said delivery electrode belongs (3) and said detecting means (22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34) generate said impedance spectrum across frequencies of said excitation signals acquired by said return electrode (4), so that said device (1 ) is suitable for allowing an impedance measurement of the skin of said person to be performed, in said area, by means of said pairs of electrodes (3, 4) of said matrix.