JPWO2009150744A1 - Sleep state monitoring device, monitoring system, and computer program - Google Patents

Abstract

In order to measure the sleep state at home, a pressure waveform acquisition unit 10 that obtains a pressure waveform from a pressure detection unit that is in contact with the user's body, and a pulsation waveform is extracted by performing predetermined processing on the pressure waveform. Sleep provided with a pulsation extraction unit 22, a pulsation interval calculation unit 24 that calculates a pulsation interval, and a sleep stage determination unit 26 that determines a sleep stage that is a stage of the user's sleep depth from the pulsation interval Health monitoring is performed by using a state monitoring device and collecting data on beat intervals during sleep through a computer network.

Description

  The present invention relates to a sleep state monitoring device, a monitoring system, and a computer program.

  Currently, it is required to manage the quality of sleep as one of the methods for managing human health and appropriately managing mental and physical stress. In order to specifically evaluate the quality of sleep, sleep is classified into six categories, that is, wakefulness, REM (Rapid Eye Movements) sleep, and stage 1 (S1) to stage 4 (S4). For this purpose, electrical measurement is usually used. In addition, awakening, REM sleep, S1 to S4, the depth of sleep increases in this order, but in the transition of the normal sleep state, REM sleep does not occur immediately after the start of sleep, and once deep sleep (S3 or When the sleep becomes shallower toward awakening after S4), the REM sleep state is entered. In this measurement, electrodes (dish electrodes) are attached to several parts of a person's (user or subject) body, for example, an electroencephalogram from the scalp, a myoelectric potential from the jaw, an ocular potential from the periphery of the eye, And you need to use ECG. A technique for determining a sleep state from an electroencephalogram is known as the Rechtschaffen-Kales (RK) method. A technique using an electrocardiogram is disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2003-222521). Although the evaluation of the sleep state by these measurement methods has a feature that the accuracy is high, in order to obtain a correct evaluation result, it is necessary for a specialist or a medical worker having specialized knowledge to analyze the data. In addition, since the electrodes are attached at the time of measurement for electrical measurement, the user's restraint is high, and a mental burden is imposed on the sleeping user. For this reason, these conventional techniques affect the sleep state and are difficult to perform continuous measurement over a long period of time.

  Moreover, many reports are made about the method of implement | achieving sleep state evaluation by biological information other than the above. This method has some variations depending on how the body vibration information is taken. One of them is a method of defining the body vibration magnitude as an index (Non-Patent Document 1).

  Furthermore, it has been reported that the sleep stages are classified into very large groups by studying the autonomic nerve component ratio. Non-Patent Document 3 discloses that an autonomic component ratio is obtained based on an electrocardiogram waveform and a determination is made between shallow sleep (S1 or S2) and deep sleep (S3 or S4).

Non-Patent Document 5 discloses changes in the spectrum of heartbeats in heart disease, and Non-Patent Document 6 applies the power spectrum of heartbeat variability to provide an autonomic nervous function at an early stage due to diabetes. It is disclosed that a failure can be detected.
JP 2003225211 A Watanabe Takashi, Watanabe Keijiro: Sleep stage estimation based on unconstrained measurement biological data at bedtime, Transactions of the Society of Instrument and Control Engineers, 38 (7), 581-589, (2002) Junichiro Hayano et al .: Heart rate variability and autonomic function, Biophysics, 28, 198-202, (1988) Baharav A, et al. : Fluctuations in autonomic novel activity draining sleep displayed by power spectrum of heart rate variability, 118, 118 Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology: Heart Rate Variability (HRV): Standards of Measurement, Physiological Interpretation, and Clinical Use, Circulation, 93 (5), 1043-1065, (1996) Saul JP, Arai Y, Berger RD. et al .: Assessment of Autonomous regulation in chronic congruent heart failure by heart analysis, American Journal of Cardiology, 198-American Journal of Cardio. Yamazaki, Y, Ueda, N .; Kishimoto, M et al. : Application of early stage of humanization, diabetic sub-objects, application of power of biology, 17 (application of power of biology, 17)

  A device or method that allows the user to easily check the quality of sleep while staying at home without the assistance of a specialist or health care professional makes it possible to grasp his / her health condition and manage his / her health. Becomes easier. Moreover, if a decrease in the quality of sleep can be detected easily, accurate information for diagnosis by a specialist or a healthcare professional can be given. In the method of Non-Patent Document 3, it is not only necessary to measure an electrocardiogram, but it is difficult to determine whether the sleep stage is subdivided, and it is not possible to determine whether it is sleep or wakefulness. Furthermore, it is not easy to monitor the health condition of a user by collecting data on fluctuations in the pulsation interval of the user who remains at home. An object of the present invention is to solve the above several problems.

  In the present invention, a pressure waveform acquisition unit that obtains a pressure waveform as an electric signal by a pressure detection unit that is in direct contact with any part of the user's body or through clothing, and a predetermined process is performed on the pressure waveform. A pulsation extraction unit that extracts a pulsation waveform of the user and calculates a pulsation interval that is a time interval from the previous pulsation for each pulsation in the pulsation waveform; There is provided a sleep state monitoring device including a sleep stage determination unit that determines a sleep stage that is a stage of the user's sleep depth from the beat interval. The sleep state monitoring of the present invention can also be implemented as a method or as a computer program in a computer connected to the pressure detection unit.

  In this specification, the sleep state is used to indicate all states of wakefulness and sleep such as wakefulness, REM sleep, stage 1 (S1) to stage 4 (S4), and the sleep stage refers to wakefulness from the sleep state. Used to refer to what is excluded, ie, REM sleep, S1-S4. The pulsation includes the pulsation of the heart and vibrations generated by the pulsation, for example, vibrations of the body surface due to arterial pulsations.

  In the present invention, a pressure waveform acquisition unit that obtains a pressure waveform as an electric signal by a pressure detection unit that is in direct contact with any part of the user's body or through clothing, and a predetermined process is performed on the pressure waveform. A pulsation extraction unit that extracts a pulsation waveform of a user, a pulsation interval calculation unit that calculates a pulsation interval that is a time interval from the previous pulsation for each pulsation in the pulsation waveform, and a computer A monitoring unit connected to a network including a data transmission unit for transmitting data through the network; and receiving time series data including at least a pulsation interval from the device through the computer network a plurality of times. A sleep state monitoring system including a storage unit for recording the time-series data corresponding to a user, the computer network Any computer connected to the network displays the time-series data received multiple times as a graph against time in association with the user, and the fluctuation of the user's pulsation interval in a certain past period A sleep state monitoring system is provided that includes a data display for presenting changes. This sleep state monitoring system can also be implemented as a program in a computer that can be connected to the monitoring unit through a computer network.

  According to any embodiment of the present invention, which sleep is awake or sleeping, or which user is sleeping, without restraining the user and affecting the sleep state It becomes possible to monitor a sleep state such as whether it is a stage. In addition, according to any embodiment of the present invention, it is possible to monitor the health condition of the user based on fluctuations in the pulsation interval.

The block diagram which shows embodiment of the sleep state monitoring apparatus of this invention. The flowchart which shows embodiment of the sleep state monitoring method of this invention. The flowchart which shows the process which determines whether it is sleep or awakening in embodiment of the sleep state monitoring method of this invention. The flowchart which shows the process which determines a sleep stage in embodiment of the sleep state monitoring method of this invention. The flowchart which shows the process which determines a sleep stage by the spectrum pattern method in embodiment of the sleep state monitoring method of this invention. The flowchart which shows the process which determines a sleep stage by the autonomic nerve component ratio method in embodiment of the sleep state monitoring method of this invention. The block diagram which shows embodiment of the sleep state monitoring system of this invention. The example of the computer screen which shows the result of having performed the process which specifies R wave in the Example of this invention. It is an example of the computer screen which shows the result of having obtained the power spectrum of RR space | interval from the body vibration obtained from the test subject in the Example of this invention, and is an arousal state (FIG. 9 (A)) and S1-S4 (FIG. 9 (B)). To FIG. 9 (E)) and REM sleep (FIG. 9 (F)). The example of the computer screen which shows the result of having determined the sleep state by the body vibration obtained from the test subject in the Example of this invention. The example of the computer screen which compares and shows the result of having determined the sleep state automatically by the body vibration obtained from the subject in the embodiment of the present invention and the result determined by the conventional method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sleep state monitoring apparatus 2 Monitoring part 10 Pressure waveform acquisition part 12 Air pressure sensor 14 Transducer part 16 A / D converter 20, 50 Computer 24 Beating interval calculation part 26 Sleep stage determination part 32 Respiration waveform extraction part 34 Respiration interval calculation part 36 Awakening determination unit 42 Sleep state determination unit 46 Data transmission unit 6 Sleep state monitoring system 60 Computer network 70 Storage unit 80 Data generation unit

1. Determination of Sleep State An embodiment of the present invention will be described below with reference to the drawings. In the embodiment of the present invention, the sleep state is determined from the body vibration waveform. As shown in FIG. 1, the body vibration waveform is acquired by the sleep state monitoring apparatus 1 including the pressure waveform acquisition unit 10 and the computer 20. The pressure waveform acquisition unit 10 includes an air pressure sensor 12, a transducer unit 14 that converts pressure into an electrical signal, and an A / D converter 16 that performs analog / digital conversion of the electrical signal. These are collectively referred to as a pressure waveform acquisition unit 10. The air pressure sensor 12 is disposed on the bed 100, for example, and is made so that a user can lie on the air pressure sensor 12. For example, a sponge-like stuffing is enclosed in a highly air-tight bag-like envelope, and it has a thickness of about 1 cm to 3 cm as a whole and is a cushion shape that is a square shape of 30 cm square. It is designed to be flexible and soft enough that you can sleep even when you lie down. A tube that can communicate with internal air and propagate pressure is connected to one peripheral portion of the envelope, and the tube extends to the transducer unit 14. The transducer section 14 has an airtight chamber to which the tube is connected. An opening is provided on one side of the airtight chamber, and a ceramic piezoelectric element is disposed so as to close the opening. . A pressure wave inside the pneumatic sensor 12 is transmitted to the piezoelectric element to generate an analog value piezoelectric signal, which becomes a pressure wave signal and is amplified by an appropriate amplifier circuit. The amplified pressure wave signal is input to the A / D converter 16, and a digitized pressure wave signal is output.

  The digitized pressure wave signal is input to the computer 20. The computer 20 operates as a set of functional blocks that perform predetermined processing in accordance with programmed instructions. That is, the computer 20 includes a pulsation extraction unit 22, a pulsation interval calculation unit 24, a sleep stage determination unit 26, a respiration waveform extraction unit 32, a respiration interval calculation unit 34, an awakening determination unit 36, and sleep. A state determination unit 42. The result is presented as the user's sleep state by a technique such as outputting to the monitor 44 and visually indicating the result. As described above, the sleep state monitoring apparatus according to the embodiment of the present invention is configured by the pressure waveform acquisition unit and each functional block realized by the computer 20. As will be apparent to those skilled in the art, data can be accumulated by appropriate storage means provided in the computer 20, and the start, stop, end, interruption, etc. of the process can be controlled by the input / output means. .

  Next, an outline of a process flow in the embodiment of the sleep state monitoring apparatus of the present invention will be described. The sleep state monitoring apparatus of the present invention can determine a sleep state consisting of determination of sleep or awakening and determination of a sleep stage. Specifically, as shown in FIG. 2, in order to determine the sleep state, body vibration data is first acquired (S10). And it is judged whether it is sleep or awakening (S20). If it is sleep (S30, YES), the sleep stage is further determined (S40). After that, or when it is not sleep (when it is awakening, S30, NO), a determination result is output. Thus, the process for determining the sleep state using body vibration in the embodiment of the present invention is divided into a process for determining whether a person is awake or sleeping and a process for determining a sleep stage. Although not shown, for the purpose of monitoring, this series of processing is repeated at regular intervals (for example, every minute) to periodically perform the process from data acquisition to sleep state determination, or Only the processing to be acquired can be performed periodically, the data can be stored in an appropriate storage means, and the determination processing can be performed afterwards.

  Hereinafter, a sleep stage determination method and a sleep state determination method implemented in the embodiment of the present invention will be described. FIG. 3 shows details of the step of determining whether it is sleep or awakening (FIG. 2, S20), and FIGS. 4 to 6 show details of the step of determining the sleep stage (S40).

1.1. Determination of sleep and awakening (S20)
In order to determine whether the user's sleep state is sleep or wakefulness, the present invention can be implemented by a form in which a respiratory waveform is extracted from a body vibration waveform and used. The range of the respiration waveform is naturally determined from the respiration rate of the person at rest. For example, a frequency domain component of 0.13 to 0.70 Hz in body vibration can be used as the respiration waveform. For this reason, the body vibration waveform is filtered and a frequency domain component of 0.13 to 0.70 Hz is extracted (FIG. 3, S202). From the respiration waveform, the fluctuation of the respiration interval is extracted. For this purpose, the time when the respiration waveform shows the maximum value is calculated, and that time is set as the time representative of the respiration timing (respiration peak time) (S204). By subtracting the peak time data, respiration interval data is generated (S206). Then, a coefficient of variation (CV) for the breathing interval is obtained (S208), and this is used as an index for the uniformity of the breathing interval. This is because when the user is sleeping, the breathing interval is highly uniform and the coefficient of variation is small, whereas when the user is awake, the breathing interval is uniform. This is because the value of the coefficient of variation increases as the value decreases. Specifically, the CV of the breathing interval is set as a threshold value of about 0.2 (S210), and when it is larger than that, it can be determined as an awake state (S212), and when smaller, it can be determined as a sleep state (S214). .

1.2. Sleep stage determination (S40)
The process of determining the sleep stage includes the step of identifying the timing of the pulsation by the R wave of the pulsation due to the heartbeat or pulsation (S402), and the data of the time interval (RR interval) between a certain heartbeat and the immediately preceding heartbeat The process is divided into the step (S404) of obtaining the power spectrum, the step of calculating the power spectrum of the RR interval (S406), and the step of determining the sleep stage (S42).

1.2.1. Specification of R wave timing (S402)
In the process of determining the sleep stage, first, the part of the wave corresponding to the R wave referred to in the electrocardiogram (ECG) is specified from the body vibration. The description of the R wave uses an expression of the R wave in the ECG for easy understanding, and is not limited to the one that directly corresponds to the EC G R wave. In order to measure the time interval between beats in a pressure wave transmitted to the surface of the body by a continuous heartbeat or pulsation, any characteristic waveform can be used as long as it is determined as a timing representative of each beat. is there. For this purpose, it is necessary to extract a wave corresponding to a pulsation from the body vibration waveform (FIG. 1, pulsation extracting unit 22). For this extraction, first, the body vibration waveform is band-limited to a range of 0.1 Hz to 30 Hz by a band pass filter. Next, the body vibration waveform after the filter is subjected to a second-order differentiation with respect to time, and data of acceleration of body vibration at each time is calculated. And the data for every time of the acceleration of the body vibration are further band-limited to the range of 3-30 Hz by a band pass filter, and the time when the waveform data shows a peak value is specified. The pulsation extraction unit 22 may include a differential peak processing unit 22A for that purpose. Furthermore, using a body vibration waveform with a period of less than 1 second, it was limited to the section in which the waveform data changed rapidly, and was extracted focusing on the periodicity of the body vibration waveform of about 4 seconds and the periodicity of the R wave. The peak time is corrected and determined so as to be substantially equally spaced. Since this time is a time when it is evaluated that the acceleration of body vibration is large in the range of 3 to 30 Hz, the present invention corresponds to the vibration due to ventricular excitement of the heart beat, that is, the time of the R wave in the electrocardiogram. Guesses. However, due to the nature of vibration detection in which vibration is extracted from body vibration, the time may be affected not only by vibration due to the heartbeat but also by vibration (pulsation) caused by the artery due to the heart.

1.2.2. Derivation of RR interval data (S404)
Time series data of the RR interval (time interval between a certain beat and the immediately preceding beat) is obtained from the R wave time data thus obtained (FIG. 4, S404; FIG. 1, beat interval). Calculation unit 24). The RR interval is given by subtracting the R wave time data of the immediately preceding beat from the R wave time data of each beat. The data of the RR interval is time data at each time of the unequal interval at which the pulsating R wave is detected. This data is conveniently converted into time-series data with a constant sampling interval for later processing, and interpolation processing is performed to obtain time-series data with an RR interval. For this, for example, processing such as secondary interpolation can be performed. Next, the sleep depth is determined from the time-series data of the RR interval obtained as described above.

1.2.3. Calculation of power spectrum of RR interval (S406)
The power spectrum is obtained from the time series data of the RR interval and used (S406; FIG. 1, power spectrum calculation unit 26A). Note that any known method can be used to calculate the power spectrum. For example, a fast Fourier transform algorithm or a method based on autocorrelation based on the Wiener-Khinchin theorem can be used. The window function (window function) for calculating the power spectrum is arbitrary, but data for 2 minutes is used to increase the accuracy of the determination. This point will be described later.

1.2.4. Next, the sleep stage is determined (FIG. 4, S42; FIG. 1, sleep stage determination unit 26). The determination of the sleep stage is a process of determining whether the sleeping state is REM sleep or Non-REM sleep (S1 to S4). Regarding the determination of the sleep stage, the present invention can be implemented by two embodiments. One is an embodiment (spectrum pattern method) in which the sleep stage is determined from the power spectrum pattern of the time series data of the RR interval, and the other is an index indicating the function of the autonomic nervous function from the time series data of the RR interval. Is calculated to determine the sleep stage (autonomic nerve component ratio method).

1.2.4.1. Sleep Stage Determination: Spectral Pattern Method The sleep stage determined by the conventional sleep stage determination method is associated with the power spectrum of the RR interval, and a typical spectrum pattern (“ A typical pattern ") can be obtained. Then, the sleep stage can be estimated by determining which typical pattern is similar to the power spectrum pattern (hereinafter, “unknown pattern”) of the RR interval measured for a subject.

  Details will be described with reference to FIG. The determination of which typical pattern is similar to the unknown pattern is made by determining the LF range (Low Frequency; 0.04-0.15 Hz) and the HF range (High Frequency; 0.15- 0.40 Hz) to obtain the maximum value of power (FIG. 5, S422), to obtain a value of 1 / n of the power value (n is an integer of 2 or more), and evaluate the frequency width at that value Do as. Specifically, first, n is set to 2 (S424), and a value of 1 / n of the maximum value of the power spectrum in the RR interval is obtained (S426). Then, on both sides of the frequency that gives the maximum value to the power spectrum, a frequency that is 1 / n of the maximum value is obtained, and a difference (frequency width) between the frequencies is calculated (S428). This process is repeated by incrementing n (S432) and repeating until a predetermined upper limit N (S430). Since the frequency width at that time is given to each n, the n dependence of the frequency width can be obtained. The frequency width of the unknown pattern is compared with the n dependence of the frequency width obtained in the same manner for the typical pattern, and the difference between the frequency width of the typical pattern and the unknown pattern is calculated as a residual (S434). Thus, the coincidence degree of the unknown pattern with respect to the typical pattern of each sleep stage can be obtained as a numerical value. Here, the peaks of the LF range of the unknown pattern are matched so as to match the peaks of the pattern of the LF range of the typical pattern as much as possible. Similarly, the peaks of the HF range of the unknown pattern are matched with the peaks of the pattern of the HF range of the typical pattern. Thus, no matching is performed between different frequency ranges. Then, a sleep stage that becomes a typical pattern showing the highest degree of coincidence (small residual) with respect to the unknown pattern is set as the sleep stage of the unknown pattern (S436). The frequency ranges of the LF range and the HF range described here are typical, including the description in the autonomic nerve component ratio method described later, and are not limited to the above-described frequency range strictly. For example, Setting the LF range to 0.05 to 0.15 Hz or the like is also part of the disclosure of the present invention.

  In the spectral pattern method, it is possible to determine the sleep stage, but it is not possible to determine whether it is in sleep or wakefulness, that is, in REM sleep or wakefulness.

  In order to improve the determination accuracy in the spectrum pattern method, the inventor of the present application has a VLF range (Very Low Frequency; 0.01 Hz to 0.04 Hz) in addition to the above LF range and HF range for the power spectrum of the RR interval. We have found it useful to use spectra. The spectrum in the VLF range is a spectrum that appears at a lower frequency than the LF range in the power spectrum of the RR interval. In order to correctly obtain the spectrum in the VLF range, the time series data of the RR interval needs to have data corresponding to the corresponding period, and the reciprocal of the lower limit frequency of the necessary spectrum range needs to be the window period. For example, in order to correctly obtain a power spectrum of 0.01 Hz, it is necessary to set this window period to an appropriate time of about 100 seconds. When actually measuring, for example, it is set to 2 minutes or more.

  Although the method for performing coincidence determination using a typical pattern has been described above as an embodiment of the spectral pattern method, the present invention can be implemented by any pattern determination method. For example, a learning process is performed on a neural network corresponding to a result (one of sleep stages) to be determined for a spectrum pattern, and the neural network is applied to an unknown pattern. A so-called supervised neural network learning system for determination can be used. Any other supervised learning technique can be implemented.

1.2.4.2. Sleep Stage Determination: Autonomic Nerve Component Ratio Method The sleep stage can also be determined by the autonomic nerve component ratio indicating the function of the autonomic nerve function. For this purpose, first, an LF component and an HF component are obtained in the power spectrum of the RR interval. Then, the ratio between the LF component and the HF component, that is, the LF / HF ratio (autonomic nerve component ratio) is calculated. This is because the function of the subject's autonomic nerve function can be evaluated by the LF / HF ratio (see Non-Patent Documents 2 to 4). In this analysis, as shown in FIG. 6, the power spectrum of the LF range is calculated to obtain the integral value of the range to obtain the LF component (S442), and the power spectrum of the HF range is calculated to integrate the range. A value is obtained and set as an HF component (S444). Then, an LF / HF ratio obtained by dividing the LF component by the HF component is obtained (S446). The sleep stage is determined by comparing the typical LF / HF ratio in each sleep stage with this LF / HF ratio (S448). The smaller the LF / HF ratio is, the deeper the sleep is, the deeper the sleep is, and the lighter is the sleep. However, it is not possible to determine whether the sleep is wake or wake. Moreover, since there is a large individual difference in the relationship between the REM sleep, each sleep stage of S1 to S4 and the LF / HF ratio, for example, the correspondence relationship with the determination result of the sleep stage by the spectrum pattern method is measured in advance, Adapting to each user is also effective.

  According to the above embodiment, a sleep state monitoring system or method is realized that hardly affects the sleep state of the user, can be used at home by the user, and can determine whether it is sleep or awakening. .

2. Monitoring of beat interval during sleep Next, a technique for monitoring beat during sleep will be described. FIG. 7 shows a configuration for performing this monitoring process. In the present invention, the computer 50 and the pressure waveform acquisition unit 10 are collectively referred to as the monitoring unit 2. As in FIG. 1, the body vibration waveform is acquired by acquiring the pressure waveform acquisition unit 10, that is, the air pressure sensor 12, the transducer unit 14 that converts pressure into an electrical signal, and the A / A that converts the electrical signal into analog / digital. A D converter 16 is used. Similarly, the air pressure sensor 12 can be disposed on the bed 100. Similarly to FIG. 1, the transducer unit 14 and the A / D converter 16 are connected to output a digitized pressure wave signal.

  The digitized pressure wave signal is input to the computer 50. The computer 50 operates as a set of functional blocks that perform predetermined processing in accordance with programmed instructions. That is, the computer 50 includes a pulsation extraction unit 22, a pulsation interval calculation unit 24, and a data transmission unit 46.

  The data transmission unit 46 can upload data to the storage unit 70 through a computer network 60 such as the Internet or an intranet. Data associated with the user's ID is uploaded to the storage unit 70 a plurality of times, and the upload is performed a plurality of times by connecting the data received a plurality of times in any computer connected to the computer network 60. Displayed data can be displayed in one graph. At this time, in order to display on a graph for each user, a data generation unit 80 for searching and connecting data of the same user is used. For example, it can be displayed on the monitor 86.

  The uploaded data is arbitrary time-series data including beat interval data. For example, only the time series data of the pulsation interval may be used alone, or when a sleep stage determination unit (not shown) similar to the sleep stage determination unit 26 of FIG. In addition to data, it can be time series data of the sleep stage. If functional blocks (not shown) corresponding to the respiratory waveform extraction unit 32, the respiratory interval calculation unit 34, the awakening determination unit 36, and the sleep state determination unit 42 of FIG. In addition, time-series data including a determination result of arousal or sleep can be used.

  In addition to generating data to be displayed on the monitor 86, the data generation unit 80 detects an obvious change that is different from the normal in the intensity of fluctuations found in the data of the beat interval, and generates an alarm signal. A fluctuation detecting unit 82 for outputting can be provided. The fluctuation detection unit 82 is a part of the data generation unit 80. However, if the fluctuation detection unit 82 is connected to the computer network 60 and can call up data for each user from the storage unit 70, the fluctuation detection unit 82 can be arbitrarily connected to the computer network 60. It can be provided in computer equipment.

  The fluctuation detection unit 82 monitors a change in the pulsation interval in a certain period of time determined according to the purpose (for example, an arbitrary predetermined period such as one month when data for one year is accumulated in the storage unit 70). is doing. In order to detect this change, the pulsation interval is arranged so as to be a numerical value such as a standard deviation value or a variation coefficient value of the pulsation interval data, and whether or not the value falls below a certain threshold value. Monitored at. Then, for example, an alarm signal is transmitted when the value falls below the threshold value, and is fed back to the user by appropriate means. For this purpose, for example, a method of displaying an alert on an automatically transmitted e-mail or a personalized management Web page can be used.

  Thereby, the physical condition change which appears in the beat interval measured at home can be caught quickly, the change of the user's physical condition which appears as the beat interval at the time of sleep can be known, and physical condition management can be performed.

3. Confirmation of correlation with conventional method in determination of sleep stage Regarding determination of sleep stage, in order to compare the method established in the past with the embodiment of the present invention, the subject is informed of the sleep stage according to the conventional method. An experimental result of determination and sleep determination according to the embodiment of the present invention will be described. Twenty-five men and women in their 20s were subjects, and the subjects were allowed to sleep (nap), of which 90 minutes were used for measurement.

3.1. Conventional method for determination of sleep stage The brain stage, electromyogram, electrooculogram, and electrocardiogram were collected from subjects and the sleep stage was determined by a conventional method. In order to obtain each measurement value, a plate electrode was attached to each part of the subject's body. Specifically, electrodes are applied to the top of the head for electroencephalograms, to the jaws for electromyograms, to the left and right sides of the eye for electrocardiograms, and to both wrists by ankle contact for electrocardiograms. Attached. A low-frequency amplifier was connected to the plate electrode to amplify the voltage signal, converted to a digital value by an AD converter, and recorded by a data logging computer. The sleep stage was determined by an electroencephalogram, and the method of Rechtschaffen-Kales (RK) described above was followed.

3.2. Method for Determining Sleep Stage According to Embodiment of the Present Invention An R wave was extracted from a heartbeat waveform to calculate an autonomic component ratio, and a respiratory waveform was also acquired.

  As a device for measurement and analysis for the method of the present embodiment, the pressure waveform acquisition unit 10 and the computer 20 which are the devices described in FIG. 1 are used, and in the computer, each functional block as shown in FIG. In order to operate the computer and perform the operations shown in FIGS. 4 to 6, a software module that extracts a heartbeat component and a respiratory component from body vibration, and an R wave is extracted from the heartbeat waveform to obtain a spectrum pattern method. A software module for analysis and a software module for performing the autonomic nerve component ratio method were used.

3.3. Correlation of R-wave timing FIG. 8 shows an example in which R-wave timing is specified from body vibration. The chart C8A in the upper part of FIG. 8 also shows the body vibration waveform C8A-10 and the respiratory waveform C8A-20 calculated therefrom. A waveform C8A-2 shown in the upper part of the center line C8A-00 is obtained by detecting a candidate time of the R wave from the body vibration waveform C8A-10. This detection was performed by the pulsation extraction unit 22. At this time, of the peaks P1 to P8 of the waveform C8A-2, the peak P2 ′ is erroneously detected. Since such erroneous detection occurs due to the influence of noise or the like, processing for removing the erroneous detection peak is performed. This process is performed when the time point when a candidate with an R wave is obtained and the time point when the next candidate is obtained are less than or equal to a preset time (for example, 0.5 seconds), the next candidate is This is processing that is not employed, such as processing that does not employ a waveform that is highly likely to be obtained regardless of pulsation as an R wave. This processing is performed to remove erroneous detection peaks from the candidates, and the time of the R wave is specified as shown below the center line C8A-00. In this figure, the phenomenon of 8 seconds is enlarged and displayed.

  And the generation | occurrence | production time was compared between the R wave obtained from the electrocardiogram by the conventional method, and the R wave specified from the data of the body vibration obtained by the embodiment of the present invention. As a result, the detection accuracy of the R wave generation time point obtained from the body vibration waveform measured by the air pressure sensor was 87% on average compared to the R wave generation time point obtained from the electrocardiogram. The correlation coefficient between the RR interval determined from the body vibration and the RR interval according to the electrocardiogram for the R-wave time-series data calculated in this way (secondarily interpolated at 0.1 second intervals) is: It was 0.80 to 0.95, and the average correlation coefficient was 0.87.

  The waveform C8B-10 appearing in the chart C8B in the middle of FIG. 8 is a respiratory waveform, the horizontal axis is a waveform of 11 minutes in time, and the vertical axis is a pressure waveform (arbitrary unit). Further, the waveform C8B-20 of the chart C8B is the estimated RR interval.

  A lower chart C8C in FIG. 8 is a power spectrum C8C-10 obtained from the RR interval by the method of the above embodiment. The power spectrum C8C-10 shown here is a result in a deep sleep stage, the frequency range displayed in the graph is in the range of 0.01 to 0.40 Hz, and the power spectrum has a high frequency (HF) range. A prominent peak C8C-P1 appeared at a position of 0.25 to 0.30 Hz.

3.4. Sleep stage determination And the sleep stage was determined by the method of this Embodiment from the body vibration. For determination of the sleep stage, data for 2 minutes was used as described above.

3.4.1. Spectral pattern method Specifically, the power spectrum obtained by the method described in relation to FIG. 8 is obtained from a subject in an unknown sleep state, and the spectral pattern method is applied thereto. The sleep stage was determined. First, the observation result of the spectrum to be determined by the spectrum pattern method will be described.

  9A to 9E show power spectra in the case of awakening and sleep states of S1 to S4. FIG. 9F shows a power spectrum of REM sleep. In these spectra, although values of 0.00 to 0.01 Hz and 0.40 to 0.50 Hz are also displayed on the graph, the frequency range to be used is 0.01 Hz to 0.40 Hz. As shown in these figures, the power spectrum of the RR interval has irregular fluctuations in the RR interval at the time of awakening in FIG. As a result, the power spectrum of the RR interval has only a small component in the LF and HF ranges, and the VLF range of 0.04 Hz or less is the main spectrum.

  In addition, in the shallow sleep stages S1 and S2 shown in FIGS. 9B and 9C, a rhythmic change is observed in the waveform of RR interval fluctuation (not shown), and this is reflected in the power spectrum. Clear peaks appeared in the LF and HF range spectra. The spectrum of this LF range became larger when the sleep stage shifted from S1 to S2.

  The sleep stage S1 is in the transition state from the awakening stage to the S2 stage, and a distribution close to the characteristics at the time of awakening, that is, a distribution of small power spectrum values over LF and HF was seen. Since the power spectrum of the awake state may be mixed into the sleep stage S1, it is difficult to distinguish the awake state from S1 only from the actual power spectrum. On the other hand, in the sleep stage S2 shown in FIG. 9C, the spectrum of the HF range appears more clearly than the spectrum of S1 although the spectrum of the LF range exists. Easier than state identification.

  In S3 and S4, which are deep sleep stages shown in FIGS. 9D and 9E, the power spectrum of the HF range becomes larger than the power spectrum of the LF range as sleep becomes deeper, and the peak of the HF range is the main in S4. It becomes a power spectrum. Therefore, identification of S4 and S3 is as easy as identification of S1 and S2.

  And (F) of Drawing 9 is a power spectrum pattern of REM sleep. In REM sleep that appears when sleep approaches wakefulness, the pattern is similar to wakefulness and S1, but the spectrum of the LF range is larger and more complex than in S1.

  According to the study of the present inventor, REM sleep and awakening can be distinguished by obtaining a coefficient of variation (CV) from time series data of RR intervals. Moreover, CV of respiration was also considered in the estimation of arousal. This method was effective in determining sleep awakening, mid-wake awakening, and awakening after the end of sleep. The characteristics when the observer directly observes the power spectrum at the RR interval have been described.

  And in order to make the determination of the sleep stage highly reproducible from the characteristics of the above pattern, the above-described spectrum pattern method was applied for the identification of the sleep stage. The results are shown in FIGS.

  FIG. 10 shows the body vibration waveform C10A-10 and respiration waveform C10A-20 (top chart C10A) obtained from the air pressure sensor, and the detected R-wave time series C10B-10 (second chart C10B from the top). Respiration rate C10C-10 and heart rate C10C-20 (chart C10C at the third stage from the top), power spectrum C10D-10 at the RR interval (chart C10D at the bottom of the bottom stage), and sleep stage determination example C10E-10 and It is LF / HF ratio C10E-20 (the lowermost right chart C10E). Moreover, FIG. 11 compares the determination result of the sleep state, the broken line R0 is a result determined by a conventional method using an electroencephalogram, and the broken line R1 (broken line) is a result of automatic determination by a spectrum pattern method. It is. The polygonal line R1 of the automatic determination result is the same as that shown in the chart C10E of FIG. 10, and the vertical axis represents awakening, REM sleep, and S1 to S4 in order from 1 to −4. It was obtained from the measurement data of the minute body vibration. The degree of agreement between the conventional method and the method of the example was about 75%.

3.4.2. Autonomic component ratio method (method using LF / HF ratio)
Next, an example of the autonomic nerve component ratio method will be described. The autonomic component ratio method was used to distinguish between the shallow sleep stages (S1 and S2) and the deep sleep stages (S3 and S4) from the body vibration waveform acquired under the above conditions. At this time, shallow sleep and deep sleep were judged as shallow sleep when the LF / HF ratio was greater than 0.3, and deep sleep was judged when 0.3 or less. In the range of the acquired data, the degree of coincidence between the determination result and the determination result of the sleep stage by the electroencephalogram was 80% or more. In addition, about this LF / HF ratio, since the individual difference is large, the above-described determination criterion is an example. For example, a value for each user used for determination can be separately recorded in a referable database.

3.5. Sleep / wake determination The spectral pattern method and autonomic component ratio method described above makes it difficult to distinguish between wakefulness and REM sleep, but by using the coefficient of variation of the respiratory peak (CV) and the coefficient of variation of the RR interval (CV), Both sleep states became distinguishable. The determination of sleep and wakefulness according to the embodiment of the present invention was performed based on the coefficient of variation (CV) of respiration. As a result, it was effective to set the respiration CV threshold to 0.2 and determine a value higher than that as arousal. In addition, although individual differences occurred in the coefficient of variation (CV) of the RR interval, sufficiently high reproducibility could be realized for specific individuals.

4). Beat monitoring Next, a production example of the sleep state monitoring system 6 that monitors the beat interval (RR interval) using the apparatus shown in FIG. 7 will be described. The monitoring unit 2 performs an RR interval calculation process for R wave data. The data of the RR interval is uploaded once a day to a data server that manages the storage unit 70. Although any data communication means can be used for uploading, for example, it can be performed by putting using FTP (File Transfer Protocol). The form of data storage in the storage unit 70 is arbitrary. For example, a computer file in CSV (Comma Separated Values) format for each user ID and each date using a file system folder (directory) of the data server. Multiple data can be stored. As another example, data can be stored in an appropriate database using a database management system or the like. In order to appropriately determine the timing of sleep start (sleeping), an optical sensor (not shown) is connected to the computer 50, and the timing of measurement start can be controlled by ambient illuminance information. Furthermore, in order to limit the measurement time to two sleep cycles after falling asleep, only data for 3 hours after the start of measurement can be acquired.

  The fluctuation of the RR interval is calculated from the data of the RR interval included in the CSV file. This fluctuation can be performed by calculating a coefficient of variation (CV). The data of each day divided into a plurality of CSV files are concatenated and calculated, and the fluctuation of the RR interval can be displayed following the date.

  The fluctuation detection unit 82 includes, for example, a short-term fluctuation monitoring module (not shown) that monitors fluctuations in the RR interval during the past month, and a long-term fluctuation that monitors fluctuations in the RR interval over the past year. A monitoring module (not shown) can be implemented. Here, the short-term fluctuation monitoring module and the long-term fluctuation monitoring module monitor how the fluctuation appearing in the fluctuation of the RR interval changes according to each period. In these modules, in order to monitor a user's health state, RR interval data acquired in the time in a sleep state suitable for monitoring can be extracted from the sleep time. As the time suitable for such monitoring, for example, a time in which a long-period fluctuation does not occur in the RR interval can be selected, or a time in which the sleep stage is in S3 or S4 can be selected. For such a purpose, the sleep state monitoring system 6 shown in FIG. 7 includes the sleep stage determination unit 26, the respiratory waveform extraction unit 32, the respiratory interval calculation unit 34, the awakening determination unit 36, and the sleep state determination shown in FIG. By further adding functional blocks such as the unit 42, the operations of the short-term fluctuation monitoring module and the long-term fluctuation monitoring module can be controlled by outputs from these functional blocks. Thus, in the sleep state monitoring system 6 shown in FIG. 7, it is possible to continuously monitor how the fluctuation of the RR interval fluctuates without placing a special burden on the user at home. .

5. Summary As described above, in the embodiment of the present invention, heart rate variability was extracted from the air pressure sensor, the R wave was detected, and the R wave could be specified with high accuracy in comparison with the electrocardiogram. Moreover, sleep and wakefulness could be appropriately distinguished by the coefficient of variation (CV) of the respiratory peak and the coefficient of variation of the R wave. Furthermore, the power spectrum of the RR interval was calculated from the specified R wave, and it was shown that the sleep stage can be accurately determined by the spectrum pattern method and the autonomic component ratio method.

  When using the R-wave coefficient of variation in sleep / wake determination or when using the autonomic component ratio method for sleep stage determination, although individual differences remain, for certain subjects High reproducibility was obtained.

  Furthermore, it is possible to continuously monitor how the fluctuation of the RR interval fluctuates without placing a special burden on the user at home.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications, changes and combinations can be made based on the technical idea of the present invention. . For example, in determining a pattern, a suitable artificial intelligence system is used to learn the relationship between the power spectrum pattern of the RR interval and the determination result made by the conventional method at the same time, and the sleep stage determination result is obtained from the power spectrum. Obtainable. In addition, for a determination that an individual difference cannot be avoided (for example, a determination based on the LF / HF ratio), a determination adapted to each subject can be performed using a file that determines a determination criterion for each subject.

  Further, the system shown in FIG. 7 can monitor and transmit changes in the interval between pulsations to a user or a medical worker. The user can take measures such as receiving an examination at a medical institution based on the information.

Claims (22)

A pressure waveform acquisition unit that obtains a pressure waveform as an electric signal by a pressure detection unit in contact with any part of the user's body directly or through clothing;
A pulsation extraction unit that performs a predetermined process on the pressure waveform to extract a pulsation waveform of the user;
For each beat in the beat waveform, a beat interval calculating unit that calculates a beat interval that is a time interval from the immediately preceding beat;
A sleep state monitoring device comprising: a sleep stage determination unit that determines a sleep stage that is a stage of the user's sleep depth from the pulsation interval. A respiration waveform extraction unit that performs a predetermined process on the pressure waveform to extract a respiration waveform;
For each breath in the breathing waveform, a breath interval calculation unit that calculates a breath interval that is a time interval from the immediately preceding breath;
The sleep state monitoring apparatus according to claim 1, further comprising: an awakening determination unit that determines whether the user is sleeping or awake from the breathing interval.   The sleep state monitoring device according to claim 2, wherein the awakening determination unit calculates a fluctuation coefficient of a beat interval from the beat interval, and determines whether it is sleep or awakening based on the fluctuation coefficient of the beat interval. .   The sleep state monitoring device according to claim 2, wherein the awakening determination unit calculates a variation coefficient of a breathing interval from the breathing interval, and determines whether it is sleep or awakening based on the variation coefficient of the breathing interval.   The sleep state monitoring apparatus according to claim 1, wherein the pulsation interval calculation unit includes a differential peak processing unit that identifies a time indicating the timing of each pulsation from the pulsation waveform by combining differential processing and peak determination. . The sleep stage determination unit
A power spectrum calculation unit for calculating a power spectrum about fluctuation of the beat interval from time series data of the beat interval;
The sleep state monitoring apparatus according to claim 1, further comprising: a spectrum pattern analysis unit that determines a sleep stage using a pattern indicated by the power spectrum as a determination target.   The sleep state monitoring apparatus according to claim 6, wherein the spectrum pattern analysis unit includes a pattern determination unit based on learning of a neural network.   The sleep stage determination unit calculates a low frequency component and a high frequency component for fluctuation of the beat interval included in the time series data of the beat interval, and calculates a ratio between the low frequency component and the high frequency component. The sleep state monitoring apparatus according to claim 1, further comprising a / HF ratio calculation unit, wherein the sleep stage is determined based on a value of the ratio.   The sleep state monitoring apparatus according to claim 1, wherein the pressure waveform acquisition unit includes an air pressure sensor disposed between a bedding that supports a user's body and the body. A pressure waveform acquisition step of obtaining a pressure waveform as an electrical signal by a pressure detection unit in contact with any part of the user's body directly or through clothing;
A pulsation extraction step of extracting a pulsation waveform of the user by performing a predetermined process on the pressure waveform;
For each beat in the beat waveform, a beat interval calculating step for calculating a beat interval that is a time interval from the previous beat;
A sleep stage monitoring method comprising: a sleep stage determination step of determining a sleep stage, which is a stage of the depth of sleep of the user, from the beat interval A respiration waveform extracting step for extracting a respiration waveform by performing a predetermined process on the pressure waveform;
For each breath in the breathing waveform, a breath interval calculating step for calculating a breath interval that is a time interval from the immediately preceding breath;
The apparatus according to claim 10, further comprising: an arousal determination step of determining whether the user is sleeping or awake from a breathing interval.   The sleep state monitoring method according to claim 11, wherein the awakening determination step calculates a fluctuation coefficient of a beat interval from the beat interval and determines whether it is sleep or awakening based on the fluctuation coefficient of the beat interval. .   The sleep state monitoring method according to claim 11, wherein the awakening determination step calculates a fluctuation coefficient of a breathing interval from the breathing interval and determines whether it is sleep or awakening based on the fluctuation coefficient of the breathing interval.   The sleep state monitoring method according to claim 10, wherein the pulsation interval calculating step includes a differential peak processing step of specifying a time indicating the timing of each pulsation from the pulsation waveform by combining differential processing and peak determination. . The sleep stage determination step includes
A power spectrum calculating step for calculating a power spectrum about fluctuation of the beat interval from time series data of the beat interval;
The sleep state monitoring method according to claim 10, further comprising: a spectrum pattern analysis step of determining a sleep stage using a pattern indicated by the power spectrum as a determination target.   The apparatus according to claim 15, wherein the spectral pattern analysis step includes causing a neural network that has learned to determine a pattern.   In the sleep stage determination step, an LF that calculates a low frequency component and a high frequency component with respect to fluctuations of the beat interval included in the time series data of the beat interval, and calculates a ratio between the low frequency component and the high frequency component. The apparatus according to claim 10, further comprising a step of calculating a / HF ratio, wherein the sleep stage is determined based on a value of the ratio.   The sleep state monitoring method according to claim 10, wherein the pressure waveform acquisition step includes a step of acquiring a pressure waveform by an air pressure sensor disposed between a bedding supporting a user's body and the body.   The method according to any one of claims 10 to 18 is executed on a computer connected to any part of a user's body, directly or via clothing, and connected to a pressure detection unit that obtains a pressure waveform as an electrical signal. Computer program to let you. A pressure waveform acquisition unit that obtains a pressure waveform as an electric signal by a pressure detection unit that is in contact with any part of the user's body directly or through clothing, and performs a predetermined process on the pressure waveform to perform Data is transmitted via a computer network, a beat extraction unit that extracts a beat waveform, a beat interval calculation unit that calculates a beat interval that is a time interval from the previous beat for each beat in the beat waveform, and a computer network A monitoring unit connected to a computer network including a data transmission unit to perform,
A sleep state comprising: a storage unit for receiving a plurality of time-series data including at least a pulsation interval from the device through the computer network, and recording the time-series data in association with the received time-series data; A monitoring system, wherein any one of the computers connected to the computer network displays the time-series data received multiple times in association with a user as a graph with respect to time, and the user in a past period A sleep state monitoring system comprising a data display unit that presents a change in fluctuation of the pulsation interval.   Any one of the computers connected to the computer network detects a fluctuation in a short period shorter than the period with respect to a numerical value indicating fluctuation of the pulsation interval in the data of the pulsation interval of the user in a past period. The sleep state monitoring system according to claim 20, further comprising a fluctuation change detection unit that outputs an alarm signal.   A pressure waveform acquisition unit that obtains a pressure waveform as an electric signal by a pressure detection unit that is in contact with any part of the user's body directly or through clothing, and performs a predetermined process on the pressure waveform to perform Data is transmitted via a computer network, a beat extraction unit that extracts a beat waveform, a beat interval calculation unit that calculates a beat interval that is a time interval from the previous beat for each beat in the beat waveform, and a computer network 23. A computer program for operating a computer that is connected to a monitoring unit connected to a computer network through the computer network as a computer according to claim 20 or 21.

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