JP2012205784A - Biological signal measurement device, bed for biological signal measurement, and biological signal measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means for simultaneously measuring both electrocardiographic signals and respiratory information with sufficient accuracy using three electrodes.SOLUTION: A biological signal measurement device includes: first-third electrodes 11-13; ground 16 connected with each of the first-third electrodes 11-13 via capacitors 20-22 (or resistors); a first separation circuit 14 to which signals from the first electrode 11 and signals from the third electrode 13 are input respectively via buffers 17 and 19, and the ground 16 is connected as the ground of the circuit; and a second separation circuit 15 to which signals from the second electrode 12 and the signals from the third electrode 13 are input respectively via buffers 18 and 19, and the ground 16 is connected as the ground of the circuit. The first and second separation circuits 14 and 15 have a separation filter for separating the input signals into respiratory components and electrocardiogram components.

Description

  The present invention relates to a biological signal measuring device, a biological signal measuring bed, and a biological signal measuring method.

  By measuring biological information such as electrocardiogram signals and respiratory information, early detection and prevention of diseases, maintenance and management of health, and evaluation and confirmation of therapeutic effects are performed.

  As a commercially available apparatus for monitoring biological information at home, there is an apparatus that adheres an adhesive electrode to the skin and monitors heartbeat and respiratory fluctuation. However, when sticky electrodes are used, the burden on the skin during long-term monitoring is great, causing rashes and irritation, and there is a risk of skin peeling when the electrodes are replaced.

  Therefore, the present inventors invented a means for measuring an electrocardiogram from the extremities via a commercially available cloth by applying the principle of capacitive coupling, and published in 2004 (Non-patent Document 1).

  The present inventors also provided means for measuring an electrocardiogram waveform similar to the lead II from a supine adult subject by placing an electrode of a conductive cloth at an appropriate position (near the back side of the shoulder rib) under the bed sheet. Invented and published in April 2007 (Non-Patent Document 2).

  In addition, the present inventors have (1) a means for measuring an electrocardiogram waveform through pajamas and sheets, and (2) a means for enabling measurement not only in a supine position but also in a lateral position by using a belt-like cloth electrode, And (3) By inventing a means that can expect an R wave detection rate close to 100% in a sleep state with little body movement by narrowing the pass band of the filter to 5-40 Hz, it was announced in October 2007 (non- Patent Document 3).

  Furthermore, the present inventors invented a means for simultaneously measuring a narrow-band electrocardiogram and respiratory information in a state in which an infant wearing a commercial underwear is laid on a mattress provided with a cloth electrode, and announced in February 2009. (Non-Patent Document 4).

Akinori Ueno, three others, “Derivation of an electrocardiogram based on capacitive coupling from an electrode through a cloth”, IEEJ Transactions C, September 2004, Vol. 124, No. 9, p. 1664-1671 Akinori Ueno, 5 others, “Capacitive sensing of electrocardiographic potential through cloth from the dorsal surface of the body in a supine position-A preliminary study”, IEEE Transaction on Biomedical Engineering, April 2007, Vol. 54, No. 4 , P. 759-766 Akinori Ueno, two others, “Fundamental study of bedding built-in non-contact ECG monitor for home health care”, IEEJ Transactions C, October 2007, Vol. 127, No. 10, p. 1792-1799 Hiroyoshi Yama, Akinori Ueno, “Simple unconstrained measurement of infant's narrow-band electrocardiogram and respiratory information using capacitive sheet sensor”, Biomedical Engineering, February 2009, Vol. 47, No. 1, p. 42-50

  In the technique described in Non-Patent Document 4, three electrodes are prepared, one electrode is brought into contact with the subject's buttocks through a cloth, the electrode is used as a ground, and the remaining two electrodes are similarly formed through the cloth. This is used as a differential electrode in contact with each of the chest back and abdominal back, and an electrocardiogram signal and respiratory information are simultaneously measured by a separation filter.

  However, in the case of the technique described in Non-Patent Document 4, an electrocardiogram signal and respiratory information can be measured simultaneously, but there is room for improvement in terms of measurement accuracy. That is, the measurement accuracy of one of the biological signals (electrocardiogram signal and respiratory information) measured at the same time may be insufficient.

  Accordingly, an object of the present invention is to provide means for simultaneously measuring an electrocardiogram signal and respiratory information with sufficient accuracy using three electrodes.

  According to the present invention, the first to third electrodes, the ground connected to each of the first to third electrodes via a capacitor or a resistor, the signal from the first electrode, and the third electrode Are input through a buffer, and each of the signals from the second electrode and the third electrode is connected to the first separation circuit in which the ground is connected as the circuit ground. And a second separation circuit to which the ground is connected as a circuit ground, and the first and second separation circuits are configured to breathe input signals. A biological signal measuring device having a separation filter for separating a component and an electrocardiogram component is provided.

  According to the present invention, the first to third electrodes, the ground connected to each of the first to third electrodes via a capacitor or a resistor, the signal from the first electrode, and the third Each of the signals from the first electrode is input through a buffer, and the first separation circuit to which the ground is connected as the ground of the circuit, the signal from the second electrode, and the third electrode Each of the signals is input via a buffer, and the ground is connected as a circuit ground. The second separation circuit is connected to the circuit, and the first and second separation circuits receive the input signal. A biological signal measuring device having a separation filter that separates into a first frequency band and a second frequency band is provided.

  Moreover, according to this invention, the bed for biological signal measurement provided with either of the said biological signal measuring apparatuses is provided.

  Further, according to the present invention, there is provided a biological signal measurement method using the biological signal measurement bed, wherein the mattress is covered with a sheet, and the first to third electrodes are covered with the sheet. A biological signal measurement method is provided in which a subject lies on top and measures a biological signal.

  According to the present invention, it is possible to simultaneously measure an electrocardiogram signal and respiratory information with sufficient accuracy using three electrodes.

It is an example of the block diagram of the biological signal measurement bed of this embodiment. It is an example of the plane schematic diagram of the 1st thru | or 3rd electrode and mattress of this embodiment. It is a figure which shows an example of a structure of the 1st and 2nd isolation | separation circuit of this embodiment. It is an example of the block diagram of the difference separation filter of this embodiment. It is the model figure and equivalent circuit of capacitive coupling which the biological signal measuring device of this embodiment utilizes. It is a figure for demonstrating the principle in which the biosignal measuring apparatus of this embodiment measures a respiratory component. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating the effect of this embodiment. It is a figure for demonstrating the effect of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  FIG. 1 shows an example of a block diagram of a biological signal measuring bed having the biological signal measuring apparatus of the present embodiment.

  The biological signal measuring device of this embodiment includes a first electrode 11, a second electrode 12, a third electrode 13, buffers 17 to 19, capacitors 20 to 22, a ground 16, a first separation circuit 14, and a second electrode. The separating circuit 15 is provided. Then, the first electrode 11, the second electrode 12, and the third electrode 13 are located on the mattress 24.

  As the first to third electrodes 11 to 13, any electrode used for electrocardiogram measurement and the like can be applied, and for example, cloth electrodes can be used.

  The first electrode 11 is in contact with the back of the subject (human body) through an insulator, for example, a cloth. The second electrode 12 is in contact with the abdominal back of the subject (human body) via an insulator, for example, a cloth. The third electrode 13 contacts the buttocks of the subject (human body) via an insulator, for example, a cloth.

  For example, the first to third electrodes 11 to 13 are arranged so as to be exposed on the mattress 24 as shown in FIG. The first to third electrodes 11 to 13 are covered with the bed sheet by a bed sheet (not shown) placed on the mattress 24. When the subject lies on the mattress 24 in this state, the first to third electrodes 11 to 13 come into contact with the subject (human body) through the bed sheets (insulator). In addition, the 1st thru | or 3rd electrodes 11 thru | or 13 may contact with a test subject (human body) through the clothes (insulator) which the test subject has worn in addition to (or instead of) a bed sheet. Commercially available bed sheets can be used. Commercially available clothes can also be used, but thin clothes are preferred. The first to third electrodes 11 to 13 may be embedded in the mattress 24 or may be configured to be removable from the mattress 24. In the latter case, the arrangement positions of the first to third electrodes 11 to 13 on the mattress 24 can be adjusted.

  Here, FIG. 2 shows an example of a schematic plan view of the first to third electrodes 11 to 13 and the mattress 24.

  The first to third electrodes 11 to 13 are arranged at predetermined positions in accordance with the state in which the subject lies on the mattress 24. Specifically, the first electrode 11 is disposed near the chest back of the subject lying on the mattress 24, the second electrode 12 is disposed near the abdominal back, and the third electrode 13 is disposed near the buttocks. “Head” and “Breech” shown in the figure indicate the position of the head and the buttocks of the subject who lies down. Since the positions of the chest, abdomen, and buttocks change according to the physique of the subject, it is beneficial if the first to third electrodes 11 to 13 are configured to be removable from the mattress 24. In this case, the arrangement positions of the first to third electrodes 11 to 13 can be changed to appropriate positions according to the physique of the subject.

  The first and second electrodes 11 and 12 may have a strip shape as shown, for example. And the 1st and 2nd electrodes 11 and 12 of such a shape may be arrange | positioned so that it may extend perpendicularly | vertically with the straight line which connects the test subject's head and foot | tip in a lying state. If comprised in this way, even if a test subject turns over, the test subject and the contact state of the 1st and 2nd electrodes 11 and 12 can be maintained. The first and second electrodes 11 and 12 are not limited to a linear shape as shown in the figure, and may be other shapes such as a wavy line shape or a zigzag line shape.

  The shape of the third electrode 13 can be the same as that of the first and second electrodes 11 and 12 described above. However, as shown in the figure, two linear electrodes are connected to form V A character shape may be formed. And the said V-shaped connection part may be arrange | positioned in a test subject's buttocks vicinity, and it may arrange | position so that the electrode extended from a connection part may extend in a test subject's leg | foot direction. In this way, it is possible to suppress inconvenience that the hand of the subject touches the third electrode 13. In addition, the angle of a connection part can be 90 degree | times, for example. Further, the electrode extending from the connecting portion is not limited to a straight line shape as shown in the figure, and may be other shapes such as a wavy line shape or a zigzag line shape.

  Returning to FIG. 1, the buffers 17 to 19 have a function of converting impedance, and for example, an IC having an input resistance of about 1000 GΩ can be applied. A signal is input to each of the buffers 17 to 19 from each of the first to third electrodes 11 to 13.

  The ground 16 is connected to each of the first to third electrodes 11 to 13 via each of the capacitors 20 to 22. For example, as shown in the figure, the first to third electrodes 11 to 13 can be coupled via capacitors 20 to 22, and the coupling point can be a virtual ground 16. In the illustrated example, the ground 16 is connected to the first to third electrodes 11 to 13 through the buffers 17 to 19 in addition to the capacitors 20 to 22, but does not pass through the buffers 17 to 19. It can also be configured. That is, the components (capacitors 20 to 23 and the ground 16) surrounded by the broken line 23 shown in the figure may be positioned between the first to third electrodes 11 to 13 and the buffers 17 to 19. it can. When the components surrounded by the broken line 23 are arranged at the positions shown in the drawing, a resistor can be applied instead of the capacitors 20 to 22.

  A signal from the first electrode 11 and a signal from the third electrode 13 are input to the first separation circuit 14 via buffers 17 and 19, respectively. The signal from the second electrode 12 and the signal from the third electrode 13 are input to the second separation circuit 15 via the buffers 18 and 19 respectively. Although not shown, a signal of the ground 16 is input to the first separation circuit 14 and the second separation circuit 15.

  The first and second separation circuits 14 and 15 use commercial noise from the signals input from the first to third electrodes 11 to 13 by using noise mixed from the ground 16 connected as the circuit ground. Remove noise (common-mode noise). This processing can be realized according to the conventional technology.

  The first and second separation circuits 14 and 15 have separation filters that separate the signals input from the first to third electrodes 11 to 13 into respiratory components and electrocardiogram components. For example, the separation filter separates an input signal into a first frequency band and a second frequency band. The band of the electrocardiogram component (R wave) is about 10 Hz to 100 Hz, and the band of the respiratory component is about 0.1 Hz to 1 Hz. Therefore, in the separation filter, a predetermined value between 1 Hz and 10 Hz is a boundary, a band above the predetermined position is a first frequency band (electrocardiogram component), and a band less than the predetermined value is a second frequency band ( Separated as respiratory component). The predetermined value can be set to 1 Hz, for example.

  Here, an example of the configuration of the first and second separation circuits 14 and 15 will be described with reference to FIG. The illustrated block diagram shows the first and third electrodes 11 and 13, the ground 16, the buffers 17 and 19, and the first separation circuit 14. The first separation circuit 14 includes “Differential Separation Filter”, “Inst. Amp. (Instrumentation Amplifier)”, “HPF (High Pass Filter)”, “Inv. Amp. (Inverting Amplifier)”, It has “LPF (low-pass filter)” and “Notch Filter (notch filter)”. In the illustrated block diagram, the first electrode 11 can be regarded as the second electrode 12, the buffer 17 can be regarded as the buffer 18, and the first separation circuit 14 can be regarded as the second separation circuit 15.

  As shown in FIG. 3, signals are input to the buffers 17 and 19 from the first and third electrodes 11 and 13, respectively. Hereinafter, a signal input from the first electrode 11 is referred to as a “signal of the first electrode 11”, and a signal input from the third electrode 13 is referred to as a “signal of the third electrode 13”. The buffers 17 and 19 are operational amplifier ICs having an input resistance of about 1000 GΩ, for example. Then, signals are input from the buffers 17 and 19 to the “Differential Separation Filter”. In addition, common mode noise such as commercial power supply noise is mixed from the ground 16 into the “Differential Separation Filter”.

  In the “Differential Separation Filter”, signals from the buffers 17 and 19 are input, and in-phase noise is mixed from the ground 16. The “Differential Separation Filter” removes commercial power supply noise (in-phase noise) from the signal of the first electrode 11 and the signal of the third electrode 13, and the signal of the first electrode 11. The differential component of the signal of the third electrode 13 is separated into, for example, a first frequency band (electrocardiogram component) of 1 Hz or more and a second frequency band (respiration component) of less than 1 Hz. FIG. 4 shows an example of a block diagram of “Differential Separation Filter”. As shown in the figure, according to “Differential Separation Filter”, the output of two transfer functions “HPF (High Pass Filter)” and “LPF (Low Pass Filter”) from one input. It can be seen that

  Returning to FIG. 3, in one “Inst. Amp.” (Instrumentation amplifier), the signal of the electrocardiogram component extracted from the differential component of the signal of the first electrode 11 and the signal of the third electrode 13 is Input from “Differential Separation Filter”. In the other “Inst. Amp.” (Instrumentation amplifier), the respiratory component signal extracted from the differential component of the signal of the first electrode 11 and the signal of the third electrode 13 is “Differential Separation Filter ( “Differential separation filter)”. “Inst. Amp.” (Instrumentation amplifier) amplifies the difference between the input signal of the first electrode 11 and the signal of the third electrode 13.

  “H.P.F. (High Pass Filter)” receives a signal after differential amplification from “Inst. Amp. (Instrumentation Amplifier)”. “H.P.F. (High Pass Filter)” to which the respiratory component signal is input removes a frequency band of, for example, less than 0.1 Hz from the input signal. On the other hand, “H.P.F.” (high pass filter) to which an ECG component signal is input removes a frequency band of, for example, less than 10 Hz from the input signal.

  The “Notch Filter” is input with an ECG component signal obtained by removing a frequency band of less than 10 Hz from “H.P.F. (High Pass Filter)”. The “Notch Filter” removes a predetermined component from the input signal according to the area where the measurement is performed. For example, when the region where measurement is performed is the Kanto area, “Notch Filter” removes a frequency band near 50 Hz from the input signal.

  “L.P.F. (low-pass filter)” is input with an ECG component signal obtained by removing a frequency band near 50 Hz from “Notch Filter”. “L.P.F. (low-pass filter)” removes a frequency band of, for example, 40 Hz or more from the input signal.

  One “Inv.Amp.” (Inverted amplifier) receives a respiratory component signal from “H.P.F.”. The other “Inv.Amp.” (Inverting amplifier) receives the ECG component signal from “L.P.F.” (low-pass filter). Inv. Amp. (Inverting amplifier) amplifies the input signal. The amplification degree may be 1000 times, for example.

  Note that the configurations of the first and second separation circuits 14 and 15 shown in FIG. 3 are merely examples, and other configurations may be employed.

  Next, the effect of this embodiment is demonstrated.

(1) First, the measurement principle of the biological signal measuring apparatus of this embodiment will be briefly described.

  FIG. 5 shows a model diagram of capacitive coupling and an equivalent circuit used by the biological signal measuring apparatus of the present embodiment. As shown in the figure, in the case of the present embodiment, the first to third electrodes 11 to 13 (“Fabric electrode” in the figure) are connected to the human body via an insulator such as clothes (“clothes” in the figure). ("Skin" in the figure). In the case of this configuration, a capacitor is formed by a combination of a human body (conductor), clothes, etc. (insulator) and first to third electrodes 11 to 13 (conductor). Hereinafter, a portion where the human body (conductor) -clothes (insulator) -first to third electrodes 11 to 13 (conductor) are combined in this manner is referred to as a “coupled portion”. In the present embodiment, the AC biosignal is derived through the capacitance of the coupling portion.

  Next, the principle of measurement of the respiratory component will be described with reference to FIG. In the case of the present embodiment, the pressure at the joint changes due to movement of the subject's chest and abdomen accompanying breathing. And if the thickness of clothes etc. (insulator) changes with the change of the pressure of a joint part, the capacity value of a joint part will change. That is, the respiratory change is superimposed on the output voltage as a baseline change.

  These details are described in Non-Patent Documents 1 to 4.

(2) Next, FIG. 7 shows data obtained by simultaneously measuring a signal of an electrocardiogram component and a signal of a respiratory component using the biological signal measurement bed of this embodiment and a commercially available device at the same time.

  The data shown as “(b) electrocardiogram: chest (prototype device)” in the figure uses the biological signal measurement bed of this embodiment, and the first electrode (arranged near the chest) and the third electrode (near the buttocks) Is a signal of an electrocardiogram component detected by using the first electrode (arranged in the vicinity of the chest) and the third electrode (in the vicinity of the buttocks). Is a signal of a respiratory component detected by using (1).

  In addition, data shown as “(c) electrocardiogram: abdomen (prototype device)” in the drawing uses the biological signal measurement bed of this embodiment, and the second electrode (arranged in the vicinity of the abdomen) and the third electrode ( The signal of the electrocardiogram component detected by using the biological signal measurement bed of the present embodiment is the second electrode, and is the signal of the electrocardiogram component detected by using the biological signal measurement bed of the present embodiment. It is the signal of the respiratory component detected using (placed near the abdomen) and the third electrode (placed near the buttocks).

  In addition, the data shown as “(a) ECG: commercially available device” in the figure is a signal of an ECG component measured by a commercially available electrocardiograph, and the data shown as “(d) Respiration: commercially available device” is commercially available. It is the signal of the respiratory component measured using the respiratory transducer.

  As shown in the drawing, it can be seen that the data shown as “(b) ECG: chest (prototype device)” is almost synchronized with the data shown as “(a) ECG: commercial device”. It can be seen that the measurement accuracy of “(c) electrocardiogram: abdomen (prototype device)” is inferior to the measurement accuracy of “(b) electrocardiogram: chest (prototype device)”.

  It can also be seen that the waveform of the data shown as “(f) Respiration: Abdomen (prototype device)” is very similar to the waveform of the data shown as “(d) Respiration: Commercial device”. The waveform of the data shown as “(e) Breathing: Chest (prototype device)” is relatively similar to the waveform of the data shown as “(d) Breathing: Commercial device”, but “(f) Breathing: It can be seen that the measurement accuracy of the abdomen (prototype device) is inferior.

  From the above results, in order to measure the ECG component and respiratory component signals with sufficient measurement accuracy using the measurement principle of the present embodiment, preferred combinations of electrodes used for the measurement of the ECG component and the respiratory component respectively. I understand that there is. That is, for the measurement of the electrocardiogram component, a combination of the first electrode (arranged near the chest) and the third electrode (arranged near the buttocks) is preferable. On the other hand, for the measurement of the respiratory component, a combination of the second electrode (arranged near the abdomen) and the third electrode (arranged near the buttocks) is preferable.

  However, in the case of the technique described in Non-Patent Document 4, although three electrodes are used as in the present embodiment, one electrode is used as a ground and only the remaining two electrodes are used as differential electrodes. The combination of the working electrodes preferable for the measurement of the electrocardiogram component as described above and the combination of the differential electrodes preferable for the measurement of the respiratory component cannot be realized at the same time.

  On the other hand, in the present embodiment, the three electrodes can be combined to make the coupling point the ground, and all the three electrodes can be used as differential electrodes. Therefore, the preferred electrode for the measurement of the electrocardiogram component as described above can be used. A combination and a combination of differential electrodes preferable for measurement of respiratory components can be realized at the same time. As a result, it is possible to simultaneously measure the ECG component signal and the respiratory component signal with sufficient accuracy using the three electrodes.

(3) Further, according to the present embodiment, as a respiratory component signal, a signal measured using an electrode disposed near the chest (a signal reflecting respiratory motion of the chest) and an electrode disposed near the abdomen are used. The signals measured in this manner (signals reflecting the respiratory motion of the abdomen) can be measured simultaneously. Therefore, various analyzes can be performed using these signals. An example of analysis will be shown below.

  In recent years, the adverse effects of sleep apnea syndrome are well known. Sleep apnea syndrome includes so-called obstructive type, central type, and mixed type in which obstructive type and central type are mixed. According to the present embodiment, it is possible to estimate to which of these sleep apnea syndrome types belong. This will be described below.

  The obstructive type is a type in which an apnea occurs when the throat is clogged, and this type has a feature that when the abdomen swells, the chest becomes concave and when the chest swells, the abdomen becomes concave.

  FIG. 13 shows a respiratory waveform during normal abdominal breathing, and FIG. 14 shows a respiratory waveform in an experiment simulating obstructive apnea. 13 and 14, the upper stage is a signal reflecting the respiratory movement of the chest, and the lower stage is a signal reflecting the respiratory movement of the abdomen. As can be seen from FIG. 13, during normal abdominal breathing, the signal reflecting the respiratory motion of the chest and the signal reflecting the respiratory motion of the abdomen are in phase. On the other hand, according to FIG. 14, it can be seen that during obstructive apnea, the signal reflecting the respiratory motion of the chest and the signal reflecting the respiratory motion of the abdomen are close to opposite phases. In other words, the phase changes during obstructive apnea compared to normal abdominal breathing. This phase change is unique during obstructive apnea and is a feature that does not appear even during central apnea (described below).

  Next, the central type is a type in which an apnea occurs when the brain issues a command to stop breathing. The difference between central apnea, obstructive apnea, and normal abdominal breathing is that the action (breathing exercise) that tries to breathe is performed during obstructive apnea and normal abdominal breathing. On the other hand, during central apnea, the action (breathing movement) that tries to breathe is not performed. For this reason, in the signal reflecting the respiratory movements of the chest and abdomen during central apnea, the above phase change (change close to reverse phase) that appears during obstructive apnea does not appear. During obstructive apnea and normal abdominal breathing, a waveform change due to respiratory movement appears in the signal reflecting the respiratory movements of the chest and abdomen, but during central apnea, breathing of the chest and abdomen There is also a difference that the waveform reflecting the respiratory motion does not appear in the signal reflecting the motion.

  FIG. 8 shows respiratory waveforms in an experiment simulating a central apnea. The data shown in FIG. 8 is data obtained by simultaneously measuring a respiratory component signal using the biological signal measurement bed of this embodiment and a commercially available respiratory transducer at the same time.

  Data shown as “chest signal (prototype device)” in the figure uses the biological signal measurement bed of this embodiment, and uses the first electrode (arranged near the chest) and the third electrode (arranged near the buttocks). The data of the respiratory component detected in this manner and the data shown as “abdominal signal (prototype device)” is the second electrode (arranged in the vicinity of the abdomen) and the third electrode using the biological signal measurement bed of this embodiment. It is the signal of the respiratory component detected using (arranged in the vicinity of the buttocks). In addition, data shown as “commercial respiratory flow transducer” in the figure is a respiratory component signal measured using a commercially available respiratory transducer.

  In the case of the data of FIG. 8, in the respiratory stop state (dotted line part) specified by using a commercially available respiratory transducer, the waveform resulting from the respiratory action in both the chest signal (prototype device) and the abdominal signal (prototype device). There is no change. That is, it can be seen that the respiratory stop state (dotted line portion) is a central type.

  The mixed type is a type in which an occlusion type and a central type appear mixedly. That is, in the signal reflecting the respiratory motion of the chest and the signal reflecting the respiratory motion of the abdomen, the phase change where each signal is close to the opposite phase (occlusion type), and the respiratory stop where the phase change does not appear A state (central type) in which a waveform change due to respiratory motion does not appear in any of the waveforms reflecting the state, for example, signals reflecting the respiratory motion of the chest and abdomen, appears.

  From the above, according to the present embodiment, which can simultaneously measure a signal reflecting the respiratory motion of the chest and a signal reflecting the respiratory motion of the abdomen, these data are analyzed, and the above-described obstruction type, central type and By detecting a change peculiar to each of the mixed types, it is possible to estimate the type of sleep apnea syndrome.

(4) Here, in FIG. 9, using the biological signal measurement bed of the present embodiment, the respiratory component detected using the first electrode (arranged near the chest) and the third electrode (arranged near the buttocks) 3 shows the correlation between the minute respiratory rate calculated from the above signal and the minute respiratory rate calculated from the respiratory component signal measured simultaneously using a commercially available respiratory transducer. (A) is the result measured from the supine subject, and the correlation function is 0.821. (B) is the result measured from the subject in the lateral position, and the correlation function is 0.910. (C) is the result measured from the prone position subject, and the correlation function is 0.994. Although all show sufficient measurement accuracy, it turns out that the best measurement accuracy is obtained especially when it measures from the test subject of prone position.

  Next, in FIG. 10, from the signal of the respiratory component detected using the second electrode (arranged near the abdomen) and the third electrode (arranged near the buttocks) using the biological signal measurement bed of this embodiment. The correlation between the calculated minute respiratory rate and the minute respiratory rate calculated from the signal of the respiratory component measured simultaneously using a commercially available respiratory transducer is shown. (A) is the result measured from the subject in the supine position, and the correlation function is 0.991. (B) is the result measured from the subject in the lateral position, and the correlation function is 0.318. (C) is the result measured from the prone subject, and the correlation function is -0.057. When measured from a supine subject, sufficient measurement accuracy was shown, but when measured from a lateral and prone subject, the measurement accuracy was insufficient.

(5) Next, FIG. 11 shows data obtained by simultaneously measuring a signal of an electrocardiogram component and a signal of a respiratory component from a sleeping subject using the biological signal measurement bed of this embodiment and a commercially available device at the same time.

  The way of displaying the data is the same as in FIG. 7, but the pulse wave signal simultaneously measured using a commercially available device is shown as “(g) Pulse wave: Commercial device”. From the data, it can be seen that the same result as that described with reference to FIG. 7 can be obtained even when measured from a sleeping subject.

  Next, FIG. 12 shows the change over time in the detection rate of the R wave when measured from a sleeping subject using the biological signal measurement bed of the present embodiment. As shown in the figure, the R wave detection rate is 99.4% on average, and it can be seen that the electrocardiogram can be measured with high probability.

(6) Although it is estimated that there are about 3 million people with sleep apnea syndrome in Japan, there are 60,000 patients who are hospitalized and treated due to limited testing facilities and opportunities. It is said that the number of people is about 2%. If this condition is left as it is, it will interfere with daily life and increase the incidence of traffic accidents, and also increase the incidence of hypertension and cardiovascular disease. According to the biological signal measuring bed and the biological signal measuring device of this embodiment, it becomes possible to easily screen a person suffering from sleep apnea syndrome at home or the like. In addition, it is possible to realize excellent effects such as early detection of diseases and reduction of medical expenses.

  The biological signal measurement bed and the biological signal measurement device according to the present embodiment have been described above. According to the above description, the biological signal measurement method using the biological signal measurement bed according to the present embodiment is described. A biological signal measuring method for measuring a biological signal is described in which a subject lies on the mattress 24 and covers the first to third electrodes 11 to 13 with the sheet, and the subject lies on the sheet. Yes.

  Further, the present embodiment may be modified as follows.

  That is, in the above example, the first to third electrodes 11 to 13 are positioned on the mattress 24, but the first to third electrodes 11 to 13 may be positioned on other objects such as a mattress. It is.

  Further, in the above example, (1) the first to third electrodes 11 to 13 are disposed so as to be exposed on the mattress 24, and (2) the first to third electrodes 11 to 13 are disposed on a sheet (insulation). (3) The test subject lies on the sheet, and the “joining portion” described with reference to FIG. 5 is realized. However, other examples may be used. For example, the first to third electrodes 11 to 13 may be attached (eg, affixed) to the backing of an insulating coating (eg, fabric, vinyl material, etc.) that constitutes the outer surface of the mattress 24. In such a case, the test subject lies directly on the insulating coating of the mattress 24, whereby a “joining portion” can be realized and measurement is possible. Note that the insulating coating needs to be thin enough to function as an insulator of the coupling portion.

  In the above example, the first to third electrodes 11 to 13 are arranged on the mattress 24 and the subject lies on the measurement, but the first to third electrodes 11 are measured. It is also possible to directly attach to the subject's chest (or chest back), abdomen (or abdominal back), and buttocks via clothes instead of placing 13 to 13 on the mattress 24.

  In the above example, the principle of capacitive coupling is applied, and an example in which measurement is performed through an insulator between the first to third electrodes 11 to 13 and the skin of the subject has been described. In the example in which the first to third electrodes 11 to 13 are directly pasted and measured, the same effect can be realized.

DESCRIPTION OF SYMBOLS 11 1st electrode 12 2nd electrode 13 3rd electrode 14 1st isolation circuit 15 2nd isolation circuit 16 Ground 17 Buffer 18 Buffer 19 Buffer 20 Capacitor 21 Capacitor 22 Capacitor 23 Capacitor and ground 24 Mattress

Claims (12)

First to third electrodes;
A ground connected to each of the first to third electrodes via a capacitor or a resistor;
A first separation circuit in which a signal from the first electrode and a signal from the third electrode are each input via a buffer, and the ground is connected as a circuit ground;
A second separation circuit in which a signal from the second electrode and a signal from the third electrode are each input via a buffer, and the ground is connected as a circuit ground;
Have
The said 1st and 2nd separation circuit is a biological signal measuring device which has a separation filter which isolate | separates the input signal into a respiration component and an electrocardiogram component. First to third electrodes;
A ground connected to each of the first to third electrodes via a capacitor or a resistor;
A first separation circuit in which a signal from the first electrode and a signal from the third electrode are each input via a buffer, and the ground is connected as a circuit ground;
A second separation circuit in which a signal from the second electrode and a signal from the third electrode are each input via a buffer, and the ground is connected as a circuit ground;
Have
The said 1st and 2nd separation circuit is a biological signal measuring apparatus which has a separation filter which isolate | separates the input signal into the 1st frequency band and the 2nd frequency band. The biological signal measuring apparatus according to claim 2,
The biological signal measuring device, wherein the first frequency band is a frequency band greater than or equal to a predetermined value between 1 Hz and 10 Hz, and the second frequency band is a frequency band less than the predetermined value. The biological signal measuring apparatus according to any one of claims 1 to 3,
The biological signal measuring device in which the first electrode detects a chest signal, the second electrode detects an abdominal signal, and the third electrode detects a buttocks signal. In the biological signal measuring device according to any one of claims 1 to 4,
The biological signal measuring device in which the first to third electrodes are in contact with a human body via an insulator during measurement of a biological signal.   A biological signal measuring bed comprising the biological signal measuring device according to claim 1. The biological signal measurement bed according to claim 6,
A biological signal measuring bed having a mattress provided with the first to third electrodes. The biological signal measurement bed according to claim 7,
The biological signal measurement bed in which the first electrode, the second electrode, and the third electrode are arranged in this order. In the establishment signal measurement bed according to claim 7 or 8,
The first to third electrodes are biological signal measurement beds exposed on the surface of the mattress. In the establishment signal measurement bed according to claim 7 or 8,
The said 1st thru | or 3rd electrode is a bed for a biosignal measurement attached to the lining of the insulating coating | cover which comprises the outer surface of a mattress. A biological signal measurement method using the biological signal measurement bed according to claim 9,
A biological signal measuring method for measuring a biological signal by placing a sheet on the mattress and covering the first to third electrodes with the sheet and a subject lying on the sheet. A biological signal measurement method using the biological signal measurement bed according to claim 10,
A biological signal measuring method in which a subject lies directly on the insulating coating of the mattress and measures a biological signal.

Images