DE19532760A1 - Body impedance data acquisition system for quantitive measurement of conductive potential of body - Google Patents

Abstract

The data acquisition system provides an accurate valid measurement of human body composition consisting of fat tissue, lean tissue and body water using a quantitative measurement of the conductive potential of the body, which is based on the lean tissue content of the body. The quantitative measurement is produced as a "bio-impedance signal." The electrical signal, in ohms, is derived by measuring body impedance component of the system. The resultant signal (three digit number, between 1 and 1000 ohms) is then entered into a modifying component to accurately predict the body composition of the tested individual. The modifying component comprises prediction formulas derived from biological data inputs including: a patient's height, weight, age, and sex to determine a "population prediction variable", and is used to interpret bio-impedance readings as "population specific", i.e., specific impedance values are exhibited by various pre-defined populations of individuals.

Description

This invention relates to a device for simple and accurately measure and quantify the conductivity of a human body, which is based on a determination of the Non-adipose content based. The non- Fat tissue content as the size "total body water" (TBW, Total Body Water) defines and differentiates the Total body water according to the sizes "extracellular mass" (ECM, extracellular mass) and "intracellular mass" or "Body cell mass" (BCM) enables.

Obesity was approved by the National Institute of Health, USA, 1985 declared an independent risk factor. In fact, obesity has become a disease for explains itself. It is now part of the medical standard that Obesity diagnosed and diagnosed by a doctor at With regard to the health and well-being of the community must be treated.

A precise definition of "obesity" was difficult to give as such a definition of a provision of a percentage of body fat.

Traditionally, the "body fat percentage" has been in Research laboratories determined by people in  a hydrostatic tank were submerged to one after a method based on a hydrostatic criterion for To carry out quantification of body fat.

Hydro-densitometry (immersion in a water tank) was done generally considered the traditional standard for body together settlement analysis viewed. Despite the hydro densitome inherent biological and experimental errors (Lohman, T.G., Skinfolds and Body Density and Their Rela tion to Body Fatness: A Review, Human Biology, 53: 181-225), all other analysis methods must be compared with this if they are to be confirmed or validated.

Another known method for body fat analysis is Skin fold measurement (touch gauge). Many experienced in the Health care workers do, however Process theory for the analysis of body composition in Question asked because their reliability is questionable. Body measurement performed by experienced technicians or the anthropometry error of plus or minus nine Percent (9%) result if they ver with densitometry is compared (Katch, F.I., Katch, V.L. (1980), Measurement and Prediction Errors in Body Composition Assessment and the Search for the Perfect Equation. Research Quarterly for Exercise and Support, Vol. 51, No. 1, 249-260). In the general clinical application, the fault is the tact teaching technology probably even bigger if this through a variety of different examiners is carried out which are not trained at expert level.

Body composition analyzers have recently been introduced leads, which is a relatively new, as tetrapolar bioelek using known impedance. A such a device is known from EP-A-0 343 928.

The most important thing is that for the technology of tetrapolar bioelectrical impedance  Exam / retest reliability at 0.5% (Lukaski, H.C., Johnson, P.E., Bolonchuck, W.W. and Lykken, G.I., Assessment of Fat-Free Mass Using Bioelectrical Impedance Measurements of the Human Body), compared to an exam / repeat exam reliability of 3.8% for hydro densitometry.

In this regard, the human body is fundamental composed of two components - one is non- Fat body mass (non-fat body mass = total body water + the other listed tissues, total body water = extracellular mass + body-cell mass), which composed of muscle tissue, connective tissue and bone is; the other main ingredient is body fat. The bio electrical impedance technology quantifies the real thing Ratio of these components - the difference between the non-fat body mass which is the healthy and stuff is the executing part, and the body fat, which is the energy storage in the body. The non-fat mass contains about 75% water, in contrast the fat is made up from about 3% to 13% water. As a result, bioelek measures tric impedance technology the "healthy" part of the Body, which is the non-fat body mass. The Non-fat body mass can also total body water (TBW) + other listed fabrics may be mentioned. The whole body Water includes extracellular mass (ECM) and body cells mass (BCM).

While the previously known tetrapolar bioelectric Technology by many both in terms of reliable simplicity as a fort step compared to hydro densitometry, previously known impedance devices have imprecise bodies Per compositional analyzes generated since such known devices from a linear approach Depend on the regression equation. It is also made up of many previously known bioelectrical impedance techniques  data not possible, biological data of certain Patient groups take into account what the accuracy adversely affect body composition analysis can.

As a result, experts recognized a significant need after a precise, efficient, valid measurement approach for the Quantification of the composition of the human body pers. The present invention provides a method for quantitative measurement of the body's conductivity simple and reliable way before asking through program-generated computer masks gender spec fish measurements of body circumference and limb length and provides with newly created algorithm equations means for changing the body impedance measurements Available what scientifically validated predictions analyzing the composition of the human body produce. The present invention enables the Quantification of human performance or Obesity in a much broader area with more accurate resolution than before.

In addition, the present invention includes shooting of body section impedance signals and / or more Impedance measurements at variable frequency. This aspect of The present invention enables further subdivision the body composition in subsets of the whole body water. The special means of modifying the Kör per-section impedance and / or the impedance for several variable frequencies allow the objective nutritional and Hydration analysis in outpatient, inpatient and intensive inpatient treatment.

The device of the present invention enables one accurate measurement of the composition of the human Body, which consists of adipose, non-adipose and Body water exists. The methodology according to the invention  sees a method for simple and reliable quanti tative measurement of the conductivity of the body, which is based on the body's non-fat content (including Total body water) is based on. Furthermore, the Device two components of total body water, namely extracellular mass (ECM) and body cell mass (BCM).

The invention is also based on the measurement of Total body water (TBW) using measurements the body section impedance and the impedance at several to define variable frequencies.

The total body water (TBW) is the body cell mass (BCM = intracellular water) plus extracellular mass (ECM = extracellular water). It makes you is of considerable medical and medical value, the BCM and ECM fractions (body cell mass fractions and extracellular mass fractions) of TBW (total body water) to be able to record in different people and in the Being able to change these proportions in one person time-dependent to measure.

For example, the present invention offers the possibility speed, acute or chronic dehydration or hyperhydrity patient either with a measurement or with to measure several measurements depending on time and to quantifi adorn. These quantifications made possible preventive medical treatment of various defined hydrogenation conditions, the negative Effects of these abnormal clinical conditions mini be lubricated.

Body section impedance measurements

Here, in addition to measuring the total body pedance, impedance measurements made using sensors at the anatomically defined ends of certain bodies  sections of the human body are attached. The Body sections include 1) the right arm, 2) the right leg and 3) the trunk, but are not on this limited. The bioimpedance signal readings are generated by the device. This newly received measuring values are then created through unique research obtained formulas supported by software, what relationships and changes in relationships between the total body impedance and body values analyze section impedance. These relationships and Changes in relationships can be considered a specific ver division and / or changes in the distribution of ECM and BCM shares of total body water (TBW) qualified and be quantified. Certain derived formula methods are used here as a means of modifying the various Bioimpedance signals are used.

Impedance at multiple frequencies

It could be shown that a single predetermined one Frequency from 40 to 60 kHz the suitable frequency for accurate and precise measurement of total body impedance through the device is. Furthermore, the whole body stands pedanz (conductivity) directly related to the calculation of total body water.

Studies have shown that several variable frequencies in the Range from about 5 kHz to about 150 kHz another analy of total body water and its subsets extracellular water (ECM) and body cell mass (BCM = intracellular water).

If in particular two (or more) frequencies at the Examination of the same patient can be used allow these two (or more) measured values (in ohms) a predictive analysis of ECM and BCM. Also allowed a time-dependent performed on the same patient Analysis with two (or more) frequencies when passed through  the new software-driven means of modification be analyzed by formulas, a predictive one Output what changes from ECM to changes from BCM qualified and quantified. That this new Mit corresponding procedures for modifying formulas as well as the modified process, several, variable bio Introducing impedance frequencies are part of this application.

In addition, this invention encompasses formulas, which bodies section data, multi-frequency data and anthropomorphic data sum up.

According to the present invention, improved algorithms Mix formulas provided to find a suitable individual to define len variable set. These new formulas are possible ben the variable input of the characteristic whole body pedance, body section impedance, multi-frequency measurements and the anthropomorphic data or shape data obtained in order to a more complete predictive power at amazing static and dynamic volume states of the total To give body water percentage.

The hereby and through the additional means to change the data generated and that described in this application ne device offer the possibility of the nutritional and State of hydration of the patient under outpatient, statio nary and intensive care inpatient diagnosis and treatment scenarios easier to handle medically.

The quantitative measurement according to the present invention is more specifically referred to as a "bioimpedance signal". This electrical signal, in ohms, is from a middle component the device for measuring the body and the body intersectional impedance derived. The resulting signal (a three-digit number between 1 and 1000 ohms) is then in a modifier component entered the body the exact composition of the person examined  gene.

The modifier comprises, in one form, Prediction forecast derived from input biology data meln. This entered biology data includes: body height, weight, age and gender of a patient in order to determine a "population prediction variable".

Thus, the modifier interprets the invention according to the device, the bioimpedance measurements as "popula determined ", i.e. certain impedance values appear for different predefined population groups. This peculiarity is related to the morphological Type, to leanness, body water and age. According to The present invention takes an algorithm formula approach used for prediction formulas to a specific person assign to a set of population-specific variables.

At the beginning, the bioimpedance signal is combined with the Biology data entered into the modifier. Both Agents according to the present invention include these Data gender-specific anthropometric measurements (Body size measurements) and also the body section vaccine and the impedance at variable multiple frequencies. Then algorithm formulas modify the input signals through the appropriate correction factor. Of the Correction factor is generally not linear and out a comparison with known hydrostatically obtained Values won to produce an output. The edition is then converted into a second one using the software Set of formulas entered to be scientifically valid Generate results. The results can then be viewed through Display means can be easily represented, so that a Body composition with multiple proportions predicted can be.

Body section impedance

The present invention is a measurement of the total body impedance, which with total body water is directly related. Total body water is defined as body cell mass (BCM or intracellular water) and extracellular mass (ECM or extracellular water). By measuring the total body water, the total predicted composition of the human body.

The invention includes placing a sensor on the right hand and right foot what the farthest represents distant anatomical points at which the Total body impedance can be quantified, which means that Total body water from the bioimpedance signal of approximately 40 up to 60 kHz is predicted.

According to the approach for body section measurement Sensors on anatomically outer ends on each of the bodies sections placed. The segments are 1) right leg, 2) right arm and 3) trunk. It can be the qualitative Measuring these body sections and the changes which occur between these, used to accumulate lungs of body fluids in ECM and BCM rooms to predict.

Because body fluid is moved osmotically or liquid accumulation occurs in extracellular spaces Bioimpedance changes between the body sections. The accumulation of liquids creates various Changes in the bioimpedance relationship between the Body sections. These changes can be called distribution changes in total body water between different intracellular (BCM) and extracellular (ECM) spaces of the Be qualified.

The hull shows due to its physiological role more varied changes in bioimpedance than that Leg or arm section. Because of the accumulation of rivers  lower extremities, which are related to hydrostatic and gravitational pressures the leg section can also make extreme changes show in the bioimpedance signals.

When the ECM fluids start to accumulate, the bioimpedance signal decreases in value since the measured Body section due to the increase in fluid volume has an increase in conductivity. Increases in the river volume of the body section reduce the bio impedance values. Decreases in body fluid volume sections reduce the conductivity and thus increase the bioimpedance value.

The special application of body section related Bioimpedance measurements are in the field of birth help / gynecology. The swan for the last third Some people start the extracellular community "Collect" or increase liquid volume. This Phenomenon can turn into a pregnancy-induced Known hypertension (PIH, pregnancy induced hypertension), fatal condition.

The results of a recent PIH study show that the Use of body section related bioimpedance characteristic change in body water distribution, especially in the lower extremities, describes and it allows the doctor to measure the level and degree of liquid accumulation of body-related bioimpedance to represent measurements and diagnostic and prescribing Make assumptions to prevent the patient from being treated before PIH occurs.

Multiple frequencies

The embodiment with a single predetermined Fre frequency of around 40 to 60 kHz has proven to be an accurate and precise means of predicting total body impedance  exposed. Frequencies from about 40 to 60 kHz viewed as medium frequency bioimpedance signals. The Ge velvet body impedance is ver in different equations applies to the ratio between the sizes total body perwater (TBW), non-fat body mass (LBM) and total Predict body fat (TBF) of the individual patient.

Recent developments reveal that across multiple frequencies others with higher or lower kilohertz signal values physiological assumptions can be made, such as the fluid distribution between ECM and BCM and also the state of hydrogenation. The current assumption is that a single frequency of about 40 to 60 kHz especially or specifically the total cell mass (TCM) or the total body cell mass (BCM) and extracellular mass (ECM) measures.

Low frequency bioimpedance signals

It is believed that lower bioimpedance frequencies from about 15 to 35 kHz through extracellular masses (ECM) be worn. Due to the membrane physiology, the Liquid distribution and the electrolyte content recorded the Use of low-frequency bioelectric currents more sensitive changes to the ECM. Since it is believed that sixty percent of total body water in ECM rooms changes in the ECM volume can be changed of a person's state of hydration, which can be important for many medical records can.

The relationship between that by means of the mean frequency from about 40 to 60 kHz total body water and that by means of the low frequency measurement at about 15 to 35 kHz obtained extracellular mass can thus ver be applied, the total liquid volume more accurately determine as by means of the signal at a single Fre quenz.  

High frequency bioimpedance signals

It is believed that the use of bioimpedance free sequences of more than about 40 to 60 kHz the total cell mass "saturates" and no better prediction correlations than has a frequency of about 40 to 60 kHz. Some However, people have a physiology that is medium-free resists quent signals or a "short circuit Effect "on them, making prediction errors for the Overall composition are generated, which on a Measurement errors in the total body impedance are based. With this Person type with abnormal physiology can with a higher-frequency bioimpedance signal from about 100 to 150 kHz for the total cell mass and thus for the whole body a more accurate forecast can be made.

The higher bioimpedance frequencies from about 100 to 150 kHz have low or on people with normal physiology no bioelectrical effect, but increase the membrane permeability in people with abnormal physiology, being a better predictive value for both Body composition as well as fluid distribution Offer.

It is clear from the foregoing that the present Invention an accurate and simple device for quanti body fat as a percentage of weight provides what makes them an important tool of health safety management for the patient and the doctor in the same Way and also for use in research. It also offers the ability to make ECM and BCM and changes to predict in these fluid spaces the possibility for better medical treatment of nutritional and State of hydration of the patient.

Other features and Advantages of the present invention will follow from the the more detailed description that is described in Ver binding with the accompanying drawings, which example explain the principles of the invention is specified.  

Fig. 1 is a perspective view of first and second prescribed locations for placement of sensor electrodes in accordance with an embodiment of the present invention,

Fig. 2 is a perspective view of third and fourth prescribed locations for placement of sensor electrodes in accordance with an embodiment of the present invention,

Fig. 3 is a schematic block diagram illustrating an embodiment of the inventive device for body impedance data acquisition according to the present invention,

Fig. 4 is a circuit diagram of a test or monitoring investi signal generator according to one embodiment of the present invention,

Fig. 5 is a circuit diagram of a power supply for the apparatus according to an embodiment of the invention,

Fig. 6 is a circuit diagram of a sensor circuit according to an embodiment of the present invention,

Fig. 7 is an electrical schematic diagram of a scheme of a pin body impedance measuring device according to a imple mentation of the present invention,

Fig. 8 is a more detailed schematic of a Körperimpe impedance measuring device according to an embodiment of the present invention,

Fig. 9 is a perspective view of a ge suitable computer according to an embodiment of the present invention,

Fig. 10 is a table of a investi Chung / repeat examination-data comparison according to the present invention,

Fig. 11 is a table of comparisons between messge boards according to the present invention,

Fig. 12 is a graph showing the entire sample referred to in Example I;

Fig. 13 is a graph showing the female portion of the total sample referred to in Example I;

Fig. 14 is a graph showing the male portion of the sample referred to in Example I;

Fig. 15 is a data list formation, and to which reference is made in Example I a table,

Fig. 16 and Fig. 16 A show the body gestalts measurements according to the present invention,

Fig. 17 shows a block diagram of variable frequencies in accordance with the present invention,

Fig. 18 illustrates the body portion of the electrode locations on a patient's arm, according to one embodiment of the present invention,

Fig. 19 illustrates the body portion locations on a leg of the patient in accordance with an embodiment of the constricting vorlie invention,

Fig. 20 illustrates the body portion places on the hull of the patient according to one embodiment of the constricting vorlie invention,

Fig. 21 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 22 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 23 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 24 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 25 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 26 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 27 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 28 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 29 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 30 is an illustration of entering the body gestalts measurement values on a screen according to the present invention,

Fig. 31 is an illustration of entering the body gestalts measurement values on a screen according to the present invention.

As shown in the drawings, the present one Invention in a device for detecting body im embodies pedance data, which in combination includes:

• a) A plurality of sensor electrodes for attachment prescribed places on the body to be examined the patient,
• b) Fasteners to remove the sensor electrodes on a Kelvinbrücke bioimpedance measuring device to attach four connecting lines,
• c) means for generating one by the sensor electrodes with a variable frequency from about 5 kHz to about 150 kHz flowing current, being measured for each Frequency generates an output range from 0 to 1000 ohms becomes,
• d) means for generating input variables which biological patient data including height, weight, age and gender and bioimpedance signal level, to determine a population-specific variable
• e) means for changing that of the means for generating of an electrical impedance signal obtained Signal using the population prediction variable,  
• f) display means for displaying the resulting output signals to provide a quantitative measurement of conductivity to provide the patient's body, which on the patient's total body water content (TBW) rests,
• g) means for comparing the resulting signal with known scatterplots to provide an output signal generate which for fatty tissue, non-fatty tissue and Whole body water is representative, and
• h) second means for comparing from step (g) data obtained with known anthropometric Data to generate an output signal which is for Represent adipose tissue, non-adipose tissue and body water is tative.

Include the anthropometric data from step (h) Measured values of circumference and limb length measurements, which on 769 test subjects, and developed Prediction equations. The equations span a number of circumference measurements and limb measurements and ratio nisse, which provide with bioelectrical impedance signals be more accurate to the percentage of body fat determine. This combination of anthropometry and bio impedance improved both the validity coefficients and also SEE (standard error of estimate, standard deviation) essential, as can be seen from Example 1.

The further developed means of the present invention thus provide a new device controlled by software tion ready which the composition of the human Body on either a "clinical" or "research" Can determine accuracy level. Furthermore, a third Means for comparing and modifying data from the Steps g) and h), where body section impedance data and impedance data of several variable frequencies are used  are provided to total body water, extracellular Predict body mass and body cell mass.

According to the present invention, an electrical Kelvin bridge generated by a plurality of electrodes, which are removably attached to certain areas of the body will. Everyone is concerned before attaching the sensors fende body location scanned and preferably with a Alcohol swabs cleaned to remove skin or surface oils remove. Then each sensor electrode on the Body of the patient placed. Preferably a conductive gel used to temporarily attach the sensor to keep his place.

Sensor electrode locations - total body impedance:

• (1) The first prescribed location 10 is the back of the patient's right hand ("dorsal view"). Locate the "styloid process" (the "elevation" near the back of the wrist). Button approximately 0.5 to 1 inch (1.27 to 2.54 cm) directly across, starting from the "styloid process" (note the slight "depression" between "radius" and "ulna"). The first sensor is placed across the "styloid process" in the middle of the wrist (the center of the sensor should be directly above the "depression" described above). Note: It is recommended to arrange the electrodes so that they point away from the body (see Fig. 1).
• (2) The second prescribed location 12 is behind the finger joint (joint) of the index finger of the right hand ("Di stales end of the second metacarpal"). Scan this area. Place the second sensor directly on the hand, directly behind the index finger, but not touching it (see Fig. 1).
• (3) The third prescribed location 14 is the patient's ankle on the front of the right foot (between the "medial" and "lateral malleolus" - the "elevations" on the inside and outside of the ankle). Notice the slight "sink" in this area where the ankle merges with the upper foot. Button there. Place the third sensor so that its center directly covers the slight "dip" described above (see Fig. 2).
• (4) The fourth prescribed location 16 is the top of the right foot behind the big toe joint (the "distal" area of the first "metatarsal"). Scan this area. Place the fourth sensor on top of the right foot, behind the big toe, but not touching the big toe (see Fig. 2).
• 1.0 Placement of the sensor locations on the body sections
• 1.1 right leg
• 1.1.1 The distal mass sensor on the right foot (black lead) and the sensor for the proximal Signal (red lead) are on the same anatomical Position as for the standard tech described above nik (whole body technique) attached.
• 1.1.2 The second set of supply lines is in the Upper leg area arranged, the distal mass sensor (black lead) over the protuberance of the big one Trochanter of the femur is placed. The great trochanter is located at the top of the hip bone. The proximal Signal sensor (red lead) becomes exactly two (2) inches (5.08 cm) from the front edge of the distal mass sensor (black supply line) arranged above the large trochanter. This is a standard sensor placement procedure for everyone Patients to the examination / repeat examination Ensure reproducibility.
• 1.2 Right arm
• 1.2.1 The distal mass sensor of the right hand (black lead) and the sensor for the proximal Signal (red lead) are on the same anatomical Place as in the standard technique.  
• 1.2.2 The second set of supply lines is in the The area of the upper arm is placed near the shoulder. The before jump on the Acromion is the place for the distal mass sensor (black lead). The lead on Acromion is on Top of the shoulder arranged on the shoulder joint. Of the Proximal signal sensor (red lead) is accurate two (2) inches (5.08 cm) from the leading edge of the distal Mass sensor arranged on the projection on the Acromion. This is a standard sensor placement procedure for all patients to the Exam / Re-Exam Re ensure producibility.
• 1.3 trunk / abdomen
• 1.3.1 The first set of supply lines is in the placed upper leg area, the distal mass sensor (black lead) over the protuberance of the spring trochanter of the femur is placed. The great trochanter is located at the top of the hip bone. The sensor for the proximal signal (red lead) is exactly two (2) Inches from the leading edge of the distal mass sors (black lead) on the large trochanter arranges. This is a standard sensor placement process for all patients to the exam re-examination reproducibility si to create.
• 1.3.2 The second set of supply lines is in the The area of the upper arm is placed near the shoulder. The before jump on the Acromion is the place for the distal mass sensor (black lead). The lead on Acromion is on Top of the shoulder arranged on the shoulder joint. Of the Proximal signal sensor (red lead) is accurate two (2) inches (5.08 cm) from the leading edge of the distal Mass sensor arranged on the projection on the Acromion. This is a standard sensor placement procedure for all patients to the Exam / Re-Exam Re ensure producibility.

Power supply

The power supply of the device according to the invention is preferably provided by a single 9 volt alkaline battery (see FIGS. 3 and 5). The circuit paths are designed with safety and efficiency in mind. An on-off switch is used to conserve the battery. The life expectancy of the bioimpedance measuring device is 500 examinations.

The design of the power supply circuit enables an examination signal and a sensor circuit, to be operated in the range of specified parameters without to be dependent on a certain battery charge level. Diode protection is preferably both on performance source as well as at the power input range of the ge printed circuit board provided to prevent that a reverse current flows.

Generated to maintain an optimal functional range the device applied a 5 volt charge to the sensor and the to power digital functions.

To be a reliable and permanent source of power if the battery is low (LED) displayed when the voltage (9 volt battery) is below 6.2 volts drops.

The power consumption of the LED becomes the remaining voltage use within 30 seconds. Note: The through Average commercially available 9 volt alkaline battery is charged to 9.2 volts.

Means for generating the body impedance signal

A 9 volt battery preferably operates the means for generating the body impedance signal. It will be a Kelvin bridge system with four connection leads. The sensors described above are attached to each  Connection end connected and to the patient for correct placed impedance data acquisition.

business

As described, the body impedance device generates one Frequency that is not perceived by the human body becomes. After checking that the four sensor electrodes are placed correctly, the patient remains calm in Prone position.

The on-off switch is brought into the "on" position. The meter takes impedance measurements at a rate of 50,000 times per second. The measuring device often requires 1 to 3 seconds to stabilize while after the most exact measured value "searches". Different factors like such as the thickness of the subcutaneous fat, the skin thickness and the Body hair is used for slower impedance measurements responsibly.

Technical specifications

The preferred technical data of the means of production of the body impedance signal are as follows:

• a) Current of the examination signal device: about 800 µA nominal
• b) Variable frequency of the examination signal of the front direction: between about 5 kHz and 150 kHz nominal
• c) Input range: 0 to 1000 ohms
• d) Input impedance: about 10 megohms
• e) Accuracy: about 1%
• f) Supply current (quiescent): about 70 MA nominal
• g) negative battery supply voltage range approximately 8.5 to 10 volts
• h) positive battery supply voltage range: about 8.5 to 10 volts
• i) Battery polarity protection: double diode

Scheme

The pin diagram shown in Fig. 7 explains in detail an executed printed circuit board for the means for generating the body impedance signal.

The details of the scheme are in the following sections shown:

• 1) Sensor circuit and
• 2) Test signal generation.
  Each of these sections refers to block diagrams to explain the exact electronic configuration.
• 3) Frequency selector.

Sensor circuit

FIGS. 3 and 6 are block diagrams showing a negotiated led sensor circuit of the impedance measuring more accurately. The electronic circuitry and components include analog-to-digital (A to D) technology. In order to obtain valid bioimpedance measurements, a correct four-pole bridge device must be used. The circuit provides a four-pole bridge (bridge with four supply lines).

The sensor circuit preferably works with an 800th µA level. The sensor current supplies together with the sub Search signal generation the device.

As explained above, the bioimpedance analyzer is connected to the body via four leads. Two are connected with the right hand and two with the right Foot. The measuring current is then applied between the poles.

Examination signal generation

A variable test signal with a frequency between 5 and 150 kHz and preferably at 15-50-150 kHz is maintained by means of the components. The block diagram represented by FIGS. 3 and 4 explains the specification and current flow of the bioimpedance analyzer in more detail. The test signal configuration is calibrated at the 500 ohm level, which is selected as a center point in the measurement range from 1 to 1000 ohms of the bioimpedance analyzer.

The test signal generator remains due to the constant span 5 volts from the power supply constant. A constant power supply of 5 volts is for the Re producibility of the bioimpedance analyzer important data. A calibration of the battery discharge display at 6.2 volts provides a constant 5 volts of current source sure.

Modification of the impedance signals

The unprocessed electrical signals from the impedance measuring device are prescribed by a correlation factor for body density (BD) modified and say the Body composition ahead.

BD = 1.14111-0.0763 (weight) (impedance / size²).

Based on a given body density, a "Range of impedance measurements" expected. This area is population specific. After the body density is checked conducts and has been compared with the impedance selected a constant for the body analysis formula.

Fig. 8 illustrates a progress made through a population prediction formula.

• a) Entering biological data:
  1. Bioimpedance
• 2. Age
• 3. size
• 4. Weight
• 5. Gender
• b) Algorithmic determination of the formula constants for body analysis based on body density and impedance:
  For example, if body density is 1.9 and impedance is 400, then X = 2.835. Note: X is the formula constant for body analysis.
• c) Population prediction formula:
  When phases one (a) and two (b) are completed, the main prediction formula, modified by the algorithm, analyzes the data to predict body composition.
• For example, fat percentage = (4.95 / X-4.5).

Note: X is the constant from the algorithm.

• d) Then the fat percentage is in the below specified gender-specific formula used.

WOMEN:
% FAT = 0.457 X (IMPEDANCE% FAT) -7.38 X (SHOULDER / ABDOMEN) + 0.181 X (RIGHT THIGH) X -0.362 × (KG) + 0.500 X (GLUTEUS) + 0.236 X (ABDOMINAL 2) -0, 275 (HT) -0.380 X (HALS) + 1.529
MEN:
ANTHRO IMPEDANCE FORMULA:
% FAT = 0.773 X (IMPEDANCE% FAT) -0.341 X (ARM LENGTH + 0.303 X (SHOULDER / ABDOMEN) -0.143 X (CHEST) -4.974 × (THIGH / CALF) + 22.990.

The device according to the invention preferably comprises a connected microprocessor in order to carry out the data processing tasks for the tests and the analysis of the body composition (see FIG. 9).

The computer is preferably permanently installed and can cannot be removed from a transport housing. A 6-  Volt adapter can be used to run the microprocessor to provide with power.

Display means for displaying data

Preferably, a printer such as such as a color printer (324 CPS) used. A short letter Business description is given below.

Investigation process Height / weight and correct patient position

• (1) Note the patient's height and weight (height in inches, Weight in pounds) (1 inch ∼2.54 cm, 1 pound ∼0.45 kg). Do not use data provided by the patient. Exactly Height and weight measurements are for accurate results essential. Remove the shoes of the for both measurements Patient. Also remove the socks / pants on the right th foot. (The location for the placement of the distal sensor electrode).
• (2) Position the patient lying on his stomach one with a non-conductive surface Table. Do not examine the patient if he is on one Tile or carpet is lying. The ones in these surfaces Static electricity contained interferes with accuracy. The patient must lie on his stomach to get through disorders Minimize muscle contractions. (Contraction of antago muscles in standing or seated patients generate inaccurate impedance results).
• (3) Arrange the patient's limbs so that they lying slightly apart, hands on trunk do not touch and do not touch your feet.

Checklist

• a) Connect the sensor electrodes to the supply cables to the patient.  
• b) Remove the patient's shoes and socks or the pants on the right.
• c) Measure the size of the patient.
• d) Weigh the patient.
• e) Record the patient's height and weight on the pa client data sheet.
• f) Lay the patient on the table, prone.
• g) Scan the sensor electrode locations.
• h) Place the sensor electrodes on the right hand and on the right foot.
• i) Collect the patient's impedance measurements.
• j) Record the impedance measurements on the patient data sheet.
• j-1) Collect and record the anthropometric measurements on the paper.
• k) Select the program from the main menu and press ENTER.
• l) Give the necessary for the input of the patient data Information.
• m) remove the printout from the printer.

Explanatory examples:

The following examples are for a clearer understanding of the features of the present invention may be helpful:

Example I

A study was conducted to assess the validity of bioelectrical impedance as an accurate assessment of body composition. 249 male and female volunteers from the University of Southern California were used as test subjects. Each subject reported to the USC Exercise Physiology Laboratory in a normal hydrated state. The body composition was evaluated using hydrostatic weighing (H2O) and bioelectrical impedance (Imp). The hydrostatic weighing was performed in a sitting position in a tank using a Chatillon autopsy scale. At least 5 trials were carried out on each subject. Residual lung volume was measured using the oxygen dilution technique using a Hewlett-Packard nitrogen analyzer. Body fat was measured using the formula of Brozek et al. (4.57 / density-4.142 × 100%). The bioelectrical impedance was measured on each subject using the standard method (whole body technique). The mean body fat in men (N = 117) was 14.1% as measured by the H2O measurement and 14.3% as measured by the Imp measurement. The validity coefficient for this group was r = -0.78 and the standard error of estimate (SEE) was 3.07%. The corresponding values for the female group (N = 132) were as follows: mean body fat from H2O = 23.5%; from Imp = 23.3%; Validity coefficient, r = 0.80; SEE = 2.879%. The results of the present study support the use of the bioelectrical impedance technique as a method of determining body composition in normal healthy people (see Figures 10 to 15).

Example II

A study was carried out to determine the validity of the bioelectric impedance as an accurate determination of the Evaluate body composition. 418 male and female volunteer from the University of Southern California were used as test subjects. Any subject enrolled in USC's Exercice Physiology Laboratory in a normal hydrated state. The evaluation of the body composition was determined by hydrostatic weighing (H2O) and bioelectric impedance (Imp) [with the BioAnalogics "Consultant" system]. The hydrostatic Weighing was done in a sitting position in a tank Performed using a Chatillon autopsy scale. At least 5 attempts were made on each subject guided. The remaining lung volume was determined using the Oxygen dilution technique measured using a Hewlett Packard nitrogen analyzer was used. The body  fat was determined using the formula of Brozek et al. (4.57 / density-4.142 × 100%). The bioelectric Impedance was measured on each subject lying on their back sen. The mean body fat in men (N = 208) measured by the H2O measurement, 15.2% and by the imp measurement measured 14.4%. The area of the body fat for this group was 3-35%. The validity coefficient rient for this group was r = 0.76 and the standard standard error of estimate (SEE) was 3.34%. The corresponding values for the female group (N = 211) were the following: Medium body fat from H2O = 23.9%; out Imp = 23.4%; Range = 11-39%; Validity coefficient, r = 0.83; SEE = 3.15%. The results of the present study support the use of bioelectrical impedance technology as a method of determining the body together setting in normal healthy people.

Example III

This study was an attempt to use bioelek trical impedance to predict body composition in large and heterogeneous populations. Densitometry (H2O) and bioimpedance (BI) were at 426 Measured women and 343 men. The mean values of the Kör perfect percentage was 23% for women and 15% in the men and were for the two methods in the we considerably similar. Using a series of um catch measurements, which were carried out on 425 women and 343 men a prediction formula (BioAnalogics) used in what bioimpedance and anthropometry goes. The validity coefficients improved to R = 0.86 (women) and R = 0.85 (men), while the Standard errors to 3.08% or 2.97% for each female or male group decreased. This study confirms that bioimpedance measurements and measurements characterize can be combined to form the body composition in people from a wide range of Accurately predict body compositions.  

Example IV

The University of Southern California tried Hypo thesis to check that it is in pregnancy-induced Hypertension (PIH) is a characteristic change in Body water distribution there, which by bioelectri cal impedance is detectable. 15 outpatients with PIH were between the 37th and 42nd pregnancy week checked, the whole body elec trical bioimpedance using body composition zenzanalysators (BioAnalogics, Inc., Los Angeles, CA) certainly. At the same time, the body section impedance of the upper and lower extremities. The relationship between the impedance (I) and the volume (V) of the conductor (Water) is described by V = L2 / 1. The data are given below:

These results show that in patients with PIH a significant accumulation of water in the upper and lower extremities, which is indicated by a lower I is played for these segments. There was one proportionately larger accumulation of water in the bottom ren extremities versus the upper extremities what due to the significantly lower leg / arm ratio I is reproduced in patients with PIH. Conclusion tion: The amount and distribution of body water is at Patients with PIH, as with the electrical bio-vaccine danzvorrichtung recorded by BioAnalogics, significantly ver divorced. This study confirmed that by using of total body impedance and body section impedance Volume and distribution of TBW (total body water)  detected and preventive medical treatment possible can be light.

Accordingly, the device according to the present Invention an accurate and valid measurement of the composition of fatty tissue, non-fatty tissue and body water existing human body. The invent Teaching according to the invention is simple and reliable A method for quantitative measurement of the guideline ability of the body, which is based on the non- Fat tissue portion of the body is based.

Claims (9)

1. Device for acquiring body impedance data for the quantitative measurement of the conductivity of a body, the device comprising in combination:

• a) a plurality of sensor electrodes for attachment to prescribed locations on the body of a patient to be examined in order to form a tetrapolar system,
• b) attachment means for detachably connecting the sensor electrodes with a Kelvinbrücken bioimpedance measuring system with four supply lines,
• c) means for generating a current flow through the sensor electrodes at a frequency of approximately 40 kHz to approximately 60 kHz, a body impedance signal being generated which has an output range of approximately 0 to 1000 ohms,
• d) means for receiving input variables, which include: biological patient data comprising height, weight, age and gender, and the bioimpedance signal derived from the means specified in step c), in order to determine a population-specific variable and to generate a corresponding electrical signal ,
• e) means for processing the electrical signals which are derived from the means for generating a current flow and the means for receiving the input variables in order to produce a resulting output signal,
• f) display means for displaying the resulting output signal in order to provide a quantitative measurement of the conductivity of the patient's body on the basis of the patient's non-fatty tissue content,
• g) means for comparing the resulting output signal with a control signal in order to produce an output representation for the adipose tissue, the non-adipose tissue and the body water,
• h) second means for comparing the signal derived from step g) with known anthropometric data in order to generate an output signal representative of fat, non-fat tissue and body water,
• i) additional means for generating a current flow through the sensor electrodes at frequencies between approximately 5 kHz and approximately 150 kHz, additional bioimpedance signals being generated which have an output range of approximately 0 to 10,000 ohms,
• j) means for modifying the bioimpedance signals from i) in such a way that the sizes total body water, extracellular body mass and intracellular body cell mass for different persons or changes over time in the above-mentioned sizes total body water, extracellular body mass and intracellular body cell mass can be predicted in the same person ,
• k) additional means for releasably attaching sensor electrodes to the defined anatomical ends of body sections of the human body (e.g. leg, arm, trunk) and means for generating and measuring body section impedance signals, and
• l) additional means for processing the total body impedance, the body section impedance and the ratios thereof in connection with several variable frequencies in order to predict the amount and distribution and changes in the amount and distribution of the sizes total body water, volume of the extracellular body mass and intracellular body cell mass.

2. Device according to claim 1, characterized in that that one of the sensor electrodes is designed for this the dorsal part of the patient's right hand to be brought. 3. Device according to claim 1 or 2, characterized records that one of the sensor electrodes out is at the distal end of the second metacarpal to be attached to the patient's right hand. 4. Device according to one of claims 1 to 3, characterized characterized in that one of the sensor electrodes is formed between the medial and lateral Malleoli of the patient's right foot attached to will. 5. Device according to one of the preceding claims, characterized in that one of the sensor electrodes is designed to the distal region of the first Metatarsal attached to the patient's right foot to be attached. 6. Device according to one of the preceding claims, characterized in that the means for producing flow at a frequency of about 50 kHz work. 7. Device according to one of the preceding claims, characterized in that it also has an energy supply for the device includes. 8. Device according to one of the preceding claims, characterized in that the means for producing  a variable current between 5 kHz and 150 kHz work. 9. Device according to one of the preceding claims, characterized in that the sensor electrodes for this are trained to measure at anatomical ends of the the body section (e.g. the arm, the leg, the Hull) to be installed.