JP2020092907A - Apnea state detection system and sound sleep provision system - Google Patents

Abstract

To provide an apnea state detection system capable of grasping the presence/absence of an apnea state by detecting a characteristic of CVHR from pulsation intervals via simple calculation.SOLUTION: An apnea state detection system comprises: pulsation interval measurement means for measuring pulsation intervals of a subject's heart; short-time average pulsation interval calculation means for calculating a short-time average pulsation interval; long-time average pulsation interval calculation means for calculating a long-time average pulsation interval; pulsation interval valley calculation means for calculating a difference between the short-time average pulsation interval and the long-time average pulsation interval; pulsation interval valley determination means for determining that a location, at which a value lower than a predetermined valley depth threshold V exists, of a time series of differences between short-time average pulsation interval and long-time average pulsation interval is a single pulsation interval valley; within-predetermined determination time number-of-valleys integration means for integrating numbers of pulsation interval valleys within a predetermined determination time; and number-of-valleys comparison means for comparing the number of pulsation interval valleys with a predetermined abnormal number-of-valleys threshold P to determine an apnea state when the number of pulsation interval valleys is equal to or larger than the abnormal number-of-valleys threshold P.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apnea detection system and a sleep-provision system.

The potential number of patients with sleep apnea syndrome (SAS) is said to be 2.56 million, even if only limited to those in need of treatment. The incidence of traffic accidents in SAS patients is about 7 times higher than that of healthy people, and various lifestyle-related diseases such as drug-resistant hypertension, heart failure, atrial fibrillation, hypertension, coronary artery disease, and diabetes are complicated. A device that improves apnea status can be used to notify the apnea status one after another to improve sleep so that a traffic accident can be avoided.If SAS can be detected early through medical checkups at the workplace, economic loss due to adult diseases etc. Can be reduced.

By the way, SAS has obstructive sleep apnea syndrome (OSAS) and central sleep apnea syndrome, but in both cases, there is a periodic variation in the beat interval, and CVHR (Cyclic Variation of Heart Rate) )It is called. This CVHR has a periodicity of 25 to 120 seconds, and matches the VLF band obtained by integrating the power spectrum density of heart rate variability from 0.008 to 0.04 Hz. A method for actually detecting SAS based on this feature has been proposed (see Patent Document 1).

Although there is a method of using a long-term electrocardiogram to detect SAS by utilizing such characteristics of CVHR, an expensive Holter electrocardiograph is required to obtain a long-term electrocardiogram, and it is necessary to measure the pulse interval from the electrocardiogram. In order to derive VLF and calculate VLF, the amount of data to handle is enormous, and it cannot be used in the medical examination that many people see at the same time.

In addition, a person may roll over during sleep, and an artifact may be mixed in the electrocardiogram at such a time, so that VLF may not be calculated correctly. In addition, OSAS does not cause apnea when sleeping in the prone position (prone position) or sideways (sideways position).

As described above, SAS may also be associated with atrial fibrillation, so it is expected that SAS will detect this at the same time.

JP, 2005-160650, A Japanese Patent No. 6150825

The present invention has been made in view of the current situation as described above, and it is possible to detect the presence or absence of an apnea state by detecting the characteristics of CVHR by a simple calculation from the pulsation interval, and for example, analyze the posture of a person at the same time. A practical apnea detection system that can improve sleep without erroneous detection due to artifacts, and can also be used in combination with an atrial fibrillation detection system (disclosed in Patent Document 2 etc.) that can be used in health examinations And a sleep and sleep providing system.

The gist of the present invention will be described with reference to the accompanying drawings.

An apnea state detection system 1 for detecting an apnea state of a subject, comprising a beat interval measuring means 4 for measuring a beat interval of a subject's heart, and the beat measured by the beat interval measuring means 4. Short-time average pulsation interval calculating means 8 for calculating a short-time average pulsation interval averaged from a pulsation interval for a predetermined time X of a respiratory cycle, and a length averaged for a predetermined time Y longer than the time X. Long-time average beat interval calculation means 9 for calculating a time-average beat interval, beat interval valley calculation means 10 for calculating a difference between the short-time average beat interval and the long-time average beat interval, In the time series of the difference between the short-term average beat interval and the long-term average beat interval obtained by the beat interval valley calculating means 10, there is a value smaller than a predetermined valley depth threshold V. The pulsation interval valley determining means 11 for determining the existing portion as one pulsation interval valley and a predetermined number for accumulating the number of pulsation interval valleys determined by the pulsation interval valley determining means 11 within a predetermined determination time. The number of valleys in the determination time and the number of valleys in the pulsation interval integrated in the number of valleys in the predetermined determination time 14 are compared with a predetermined threshold value P for the number of abnormal valleys, and the number of the valleys in the pulsation interval is determined as described above. The present invention relates to an apnea state detection system characterized by comprising a valley number comparison means 16 for judging an apnea condition if the abnormal valley number threshold value P or more.

Further, in the apnea detection system according to claim 1, the pulsation interval valley determining means 11 includes the valley among the time series of the difference between the short time average pulsation interval and the long time average pulsation interval. An apnea condition characterized in that a value smaller than the depth threshold value V is continuously judged to be a predetermined valley judgment threshold value Q or more as one beat interval valley. It relates to a detection system.

Further, in the apnea detection system according to any one of claims 1 and 2, a posture measuring means 19 for measuring a posture of a subject and a standing or prone position from the posture obtained from the posture measuring means 19. Body position determining means 23 for determining whether the patient is in the lateral or lateral position, and standing or prone position based on the position information obtained by the body position determining means 23 from the time series of the pulsation intervals measured by the pulsation interval measuring means 4. Of the pulsation intervals in any of the postures of the lateral position or the lateral position, and the time series of the pulsation intervals excluding the pulsation intervals is used as the short-time average pulsation interval calculation means 8 and the long-time average. The present invention relates to an apnea state detecting system, characterized in that it comprises a predetermined body position pulsation interval excluding means 24 for transferring to the pulsation interval calculating means 9.

Further, in the apnea detection system according to any one of claims 1 and 2, body movement is performed from a posture measuring unit 19 for measuring the posture of the subject and a time series of postures obtained from the posture measuring unit 19. From the time series of the pulsation intervals measured by the pulsation interval measuring means 4 and the body motion detection means 25 for detecting A body that excludes the beat interval of time and transfers the time series of the beat interval from which the beat interval is excluded to the short-time average beat interval calculator 8 and the long-time average beat interval calculator 9. The present invention relates to an apnea state detection system, characterized in that it includes a moving beat interval excluding means (26).

Further, in the apnea detection system according to any one of claims 1 and 2, a posture measuring means 19 for measuring the posture of the subject,
From the posture obtained from the posture measuring means 19, a posture determining means 23 for determining whether the patient is standing, lying down or lying down, and a time series of the pulsation intervals measured by the pulsation interval measuring means 4, Based on the postural information obtained by the determining means 23, the pulsation interval in any of the standing position, prone position or lateral position is excluded, and the pulsation interval is excluded from the time series of the pulsation interval. A predetermined body position pulsation interval excluding means 24 for transferring to the short time average pulsation interval calculation means 8 and the long time average pulsation interval calculation means 9,
From the body movement detecting means 25 for detecting body movement from the time series of postures obtained from the posture measuring means 19, and the body movement detecting means from the time series of the pulsation intervals measured by the pulsation interval measuring means 4. The pulsation intervals before and after a predetermined time from the time when the body motion detected by 25 is excluded, and the time series of the pulsation intervals excluding the pulsation intervals is used as the short-time average pulsation interval calculation means. The present invention relates to an apnea detection system, characterized in that it comprises 8 and a beat interval excluding means 26 for body movement which is transferred to the long-term average beat interval calculating means 9.

Further, in the apnea detection system according to any one of claims 1 to 5, the valley depth threshold value V is the long-term average pulsation interval calculated by the long-time average pulsation interval calculation means 9. The present invention relates to an apnea detection system characterized by being a function.

In addition, a sleep and sleep providing system that eliminates the apnea of the subject to provide sleep, comprising: a beat interval measuring means 4 for measuring a beat interval of the heart of the subject; and the beat interval measuring means 4. An analyzer 3 that determines an apnea state from the measured pulsation intervals, and a stimulating means that eliminates the apnea state and improves sleep by generating sound or vibration to slightly awaken the subject. The present invention relates to a sleep and sleep providing system characterized by including.

In addition, a sleep and sleep providing system that eliminates the apnea of the subject to provide sleep, comprising: a beat interval measuring means 4 for measuring a beat interval of the heart of the subject; and the beat interval measuring means 4. From the measured pulsation intervals, short-time average pulsation interval calculation means 8 for calculating short-time average pulsation intervals averaged over a predetermined time X of a respiratory cycle, and a predetermined time Y longer than the time X. Long-time average beat interval calculation means 9 for calculating the long-time average beat interval, and beat interval valley calculation means for calculating the difference between the short-time average beat interval and the long-term average beat interval. 10 and a value smaller than a predetermined valley depth threshold V in the time series of the difference between the short-time average beat interval and the long-term average beat interval obtained by the beat interval valley calculating means 10. And the number of the beat interval valleys judged by the beat interval valley judging means 11 within a predetermined judgment time. And the number of pulsation interval valleys accumulated by the predetermined judgment time inner valley number integration means 14 is compared with a predetermined abnormal valley number threshold P, and the pulsation interval valley is calculated. The number of abnormal valleys is greater than or equal to the abnormal valley number threshold P, the number-of-valleys comparison means 16 determines an apnea state, and when the number-of-valleys comparison means 16 determines an apnea state, a sound or vibration is generated. The present invention relates to a sleep-providing system, which comprises a stimulating means for eliminating apnea and improving sleep by slightly awakening a subject.

Since the present invention is configured as described above, it becomes a practical apnea state detection system and a sleep asleep providing system that can detect the presence or absence of an apnea state by detecting the characteristics of CVHR from the pulsation interval by a simple calculation.

It is a structure schematic explanatory drawing of a present Example. It is a schematic structure explanatory view of example 1 of another. It is a schematic structure explanatory drawing of the example 2 of another. It is a schematic structure explanatory view of example 3 of another. It is a graph which shows the time series of the beating interval in which CVHR has occurred. It is a graph for explaining a method for detecting an apnea. It is a graph for demonstrating the change of the pulsation interval caused by body movement.

A preferred embodiment of the present invention will be briefly described with reference to the drawings showing the operation of the present invention.

When apnea is caused by sleep apnea syndrome (SAS), there is a cyclically large increase and decrease in the interval between beats called CVHR (changes have peaks and valleys). FIG. 5 shows a time series of beat intervals in which CVHR occurs. The horizontal axis represents time, the vertical axis represents beat intervals, and the place where CVHR occurs is shown in parentheses. Therefore, it is possible to detect the apnea state by SAS by searching for the periodic fluctuation of the beat interval (if it can be confirmed that CVHR is occurring). Specifically, it suffices to check whether valleys with a predetermined depth (deep valleys) periodically appear in the time series of pulsation intervals.

The present inventors have found that in the time series of the difference between the short-term average pulsation interval and the long-term average pulsation interval, there is a value smaller than a predetermined valley depth threshold V (preferably the valley depth. (Where a value smaller than the threshold value V continues for a predetermined valley judgment threshold value Q or more) is defined as one beat interval valley, and the number of beat interval valleys within a predetermined judgment time is a predetermined abnormal valley number threshold value. It was confirmed that it was possible to determine that CVHR had occurred when P or more.

Therefore, according to the present invention, the occurrence of CVHR, that is, the apnea state can be detected by a simple calculation using the pulsation interval.

Specific embodiments of the present invention will be described with reference to the drawings.

The present embodiment is an apnea state detection system 1 for detecting an apnea state of a subject, which is a beat interval measuring means 4 for measuring a beat interval of a subject's heart, and the beat interval measuring means 4. A short-time average pulsation interval calculation means 8 for calculating a short-time average pulsation interval averaged over a predetermined time X of a breathing cycle from the pulsation interval measured by the above; and a predetermined time longer than the time X. Long-time average beat interval calculation means 9 for calculating the long-time average beat interval averaged by Y, and beat interval valley calculation for calculating the difference between the short-time average beat interval and the long-term average beat interval In the time series of the difference between the short time average beat interval and the long time average beat interval obtained by the means 10 and the beat interval valley calculating means 10, the difference is smaller than a predetermined valley depth threshold value V. The beat interval valley determining means 11 that determines a place where a value exists as one beat interval valley and the beat interval valley that is determined by the beat interval valley determining means 11 within a predetermined determination time The number of valleys within a predetermined judgment time for accumulating the number of valleys, and the number of valleys of the pulsation interval accumulated by the means for accumulating valleys within the predetermined judgment time 14 are compared with a predetermined threshold value P of abnormal valleys to determine the pulsation interval. If the number of valleys is equal to or greater than the abnormal valley number threshold P, the number of valleys comparing means 16 for determining an apnea is provided.

Specifically, in the present embodiment, as shown in FIG. 1, a beat interval measuring sensor 2 provided with a beat interval measuring means 4, a short-time average beat interval calculating means 8 and a long time mean. The analyzer 3 is provided with an average beat interval calculation means 9, a beat interval valley calculation means 10, a beat interval valley determination means 11, a valley number integration means 14 within a predetermined determination time, and a valley number comparison means 16. Has been done.

Each part will be specifically described.

The sensor 2 has a beat interval measuring means 4, a beat interval saving means 5 for temporarily saving the beat interval data measured by the beat interval measuring means 4, and the temporarily saved beat. A beat interval transmitting means 6 for transmitting the interval data to the beat interval receiving means 7 of the analyzer 3 is provided.

The pulsation interval measuring means 4 uses, for example, a microcomputer or the like to measure the interval between one R wave and another R wave adjacent to it from the electrocardiogram based on the change in the voltage obtained from the electrodes, or one R wave. The pulsation interval is measured from the interval between the S wave and another S wave adjacent thereto. Therefore, if the sensor is miniaturized and attached to the skin via the electrode, the sensor can be hidden under the clothes, and the measurement can be performed without disturbing sleep. The pulsation interval measuring means 4 may be configured to measure the pulse wave from reflected light of infrared rays and measure the pulsation interval from the peak interval or the like. In this case, it suffices to fix the sensor to the earlobe, wrist, arm or the like with a clip or band, and it is easy to wear.

The beat interval data measured by the beat interval measuring means 4 is sequentially transferred to the beat interval saving means 5 and temporarily saved. When only the sensor 2 is applied to the subject for the examination, the pulsation interval data temporarily stored is about half a day. In this case, the beat interval storage means 5 can employ a semiconductor memory, a tape, or the like. Unlike the Holter electrocardiograph, there is no need to store the electrocardiogram waveform, and when a semiconductor memory is used as the beat interval storing means 5, a very small and low power consumption memory can be used, so it is small and lightweight. Thus, it is possible to configure the sensor 2 that does not burden the target person. When it is desired to determine whether or not the subject is in an apnea state in real time from the pulsation interval data of the subject in order to perform an examination or to operate a device for improving the apnea, the pulsation interval storage means 5 outputs the pulse to the outside. Since it is a temporary buffer for transferring motion interval data, it may be, for example, a random access memory in the microcomputer used for the beat interval measuring means 4. In this case, the sensor 2 can be made smaller and lighter, and the burden on the subject can be further reduced.

The beat interval data temporarily stored by the beat interval storing means 5 is transferred to the beat interval transmitting means 6.

The beat interval transmitting means 6 receives the beat interval data transferred from the beat interval storing means 5, and transfers it to the beat interval receiving means 7 provided in the analyzer 3. As a transfer method, wireless using electric waves or light, or wired connection such as USB or RS-232C can be used. When the wireless connection is used to connect the sensor 2 and the analyzer 3, the sensor 2 and the analyzer 3 can be physically separated, and the burden on the subject to whom the sensor 2 is attached is reduced. Therefore, it is suitable when it is desired to determine in real time whether or not an apnea is present from the pulsation interval data of the subject for inspection or for operating a device for improving apnea. It is also possible to use a public line such as a telephone line or the Internet, and in this case, it becomes possible to detect the apnea state remotely to the target person. Further, when a wired connection is used to connect the sensor 2 and the analyzer 3, the beat interval data can be transferred reliably and at high speed. It is suitable for transferring the interval data to the beat interval receiving means 7 via the beat interval transmitting means 6.

The analyzer 3 includes a beat interval receiving means 7, a short-time average beat interval calculating means 8, a long-time average beat interval calculating means 9, a beat interval valley calculating means 10, and a beat interval valley determining means 11. A predetermined pulsation interval valley depth storage means 12, a predetermined valley pulsation interval number storage means 13, a predetermined determination time inner valley number accumulation means 14, a valley number comparison means 16 and a predetermined valley number storage means 17 are provided. The analyzer 3 is an electronic computer or measuring instrument that performs a series of calculations, comparisons, and displays, and includes a dedicated device equipped with each of the above means, a personal computer, a tablet computer, a smartphone, a mobile phone, or a server on the Internet. Can be adopted.

The beat interval receiving means 7 receives the beat interval data from the beat interval sending means 6 of the sensor 2, and transfers it to the short-time average beat interval calculating means 8 and the long-time average beat interval calculating means 9.

The short-time average pulsation interval calculation means 8 calculates a short-time average pulsation interval SR averaged over a predetermined short time (time X) that is a time of about a respiratory cycle.

The long-term average pulsation interval calculating means 9 calculates the long-term average pulsation interval LR averaged over a predetermined long time (time Y) that is sufficiently longer than the time of the respiratory cycle.

The data calculated by both the short-time average beat interval calculation means 8 and the long-term average beat interval calculation means 9 are transferred to the beat interval valley calculation means 10.

Further, as will be described later in detail, in this embodiment, the time X is set to, for example, about 4 seconds to 8 seconds. The time Y is set to, for example, the CVHR cycle of 25 seconds to 120 seconds. Therefore, for example, by using the beat interval data measured and accumulated every time the beat is detected by the beat interval measuring means 4, the average beat interval for the past 4 seconds from the time of calculation is calculated as the short-term average beat interval SR. Then, the average beat interval for the past 25 seconds can be set as the long-term average beat interval LR. The calculation intervals of the short-time average beat interval calculation means 8 and the long-time average beat interval calculation means 9 may be the same as the beat intervals measured each time a beat is detected, for example.

The beat interval valley calculating means 10 includes a short time average beat interval SR calculated by the short time average beat interval calculating means 8 and a long time average beat interval LR calculated by the long time average beat interval calculating means 9. The average beat interval difference SR-LR of is calculated, and the result is transferred to the beat interval valley determining means 11.

The beat interval valley determining means 11 is stored in the predetermined beat interval valley depth saving means 12 of (mean time series of) the mean beat interval differences SR-LR calculated by the beat interval valley calculating means 10. When the value (beat interval) smaller than the predetermined valley depth threshold value V continues for the predetermined valley determination threshold value Q stored in the predetermined valley inner beat interval number storage means 13, this is counted as one beat. It is determined to be a moving interval valley, and the pulsating interval valley judgment result data is transferred to the valley number integrating means 14 within a predetermined judgment time. The predetermined valley depth threshold V stored in the predetermined beat interval valley depth storage means 12 is stored in the analyzer 3, but the valley depth threshold V may be set by the user. Then, the apnea detection sensitivity can be adjusted.

The pulsation interval valley determining means 11 determines not only when the value smaller than the valley depth threshold value V continues for a predetermined number, but when only one value exists, it is determined as one pulsation interval valley. It may be configured as.

The valley depth threshold V may be a function V=V(LR) of the long-term average beat interval LR of beat intervals. As the function V(LR), for example, V(LR)=αLR or V(LR)=αLR ² with α being a constant can be adopted. The predetermined number of pulsation intervals stored in the predetermined number-of-valley-intervals storage unit 13 is used to prevent the detection of sudden pulsation interval valleys and to prevent erroneous detection, as described later. Therefore, an apnea detection system in which the sensitivity and the specificity are well balanced can be configured by appropriately setting it according to the condition of the subject.

The valley number accumulating means 14 within the predetermined determination time counts how many beat interval valleys are included in the beat interval valley determination result data within the predetermined determination time, and transfers the result to the valley number comparing means 16.

The valley number comparing means 16 compares with the predetermined abnormal valley number threshold value P stored in the predetermined valley number saving means 17, and if the number of pulsation interval valleys is equal to or more than the abnormal valley number threshold value P, it is determined to be an apnea state. To do. If the threshold value P for the abnormal valley number is made small, the sensitivity is increased, but there is a risk of erroneous detection. Further, by increasing the abnormal valley threshold P, it is possible to more accurately detect the apnea state of the subject having a short beat interval variation cycle in the apnea state. Therefore, if the abnormal valley threshold P is appropriately set according to the condition of the subject, it is possible to avoid erroneous detection of the apnea detection system.

The presence/absence of the apnea state determined by the valley number comparing means 16 is transferred to the notifying means 18 for notifying the presence/absence of the apnea state. The valley number comparing means 16 and the notifying means 18 may be arranged in the same housing (analyzer 3). In this case, the transfer method depends on the wiring on the printed wiring board. Alternatively, the analyzer 3 including the valley number comparing means 16 and the notifying means 18 may be separate bodies. In this case, the transfer method may be wireless using electric waves or light, or wired connection such as USB or RS-232C. When wireless is used, the notifying means 18 and the analyzer 3 can be physically separated, and by placing only the notifying means 18 at the bedside, the apnea detection system is highly convenient for the subject. It is also possible to use a public line such as a telephone line or the Internet. In this case, it is possible to notify the subject only of the result while detecting the apnea condition remotely to the subject. The person has no trouble in disposing the analyzer 3. When a wired connection is used, power can be supplied from the analyzer 3 to the notification means 18, so that the bed can be swung when an apnea condition is detected, and the variety of notification methods is increased.

As the notification means 18, for example, a display that displays characters or images can be used. In this case, the pulsation interval data and the presence/absence of an apnea condition can be displayed in a graph to clearly indicate when the apnea condition occurs. In addition, light, sound, or vibration can be used as the notification means 18. In this case, the apnea condition can be immediately notified.

In addition, with or without the notification means 18, when the apnea is detected, the sound or vibration is generated to such an extent that the subject is slightly awakened (to the extent that the sleep state can be continued). If a stimulating means such as slightly tilting the pillow or the bed is provided, when the apnea condition is detected, the effect of eliminating the apnea condition of the subject and improving sleep can be obtained. It becomes possible to realize a sleep-sleeping system that eliminates the apnea condition and provides sleep.

The apnea detection method according to this embodiment will be described in detail.

As described above, in order to detect an apnea state by SAS, it is sufficient to check whether valleys with a predetermined depth (deep valleys) periodically appear in the time series of pulsation intervals.

This method will be described with reference to FIG. To detect "deep valleys", it is necessary to measure the depth of the valleys. As a depth standard for measuring the depth of the valley, the average of the beating intervals for a predetermined long time is used in consideration of the daily variation of the beating intervals. The predetermined long time (time Y) is preferably about 25 to 120 seconds, which is the CVHR cycle. One valley can be a group of which the difference between the pulsation interval and the average of the pulsation intervals over a predetermined long time, which is a reference for measuring the depth of the valley, is smaller than a predetermined value. However, since the pulsation interval always includes respiratory arrhythmia, the increase or decrease in the pulsation interval due to this may be identified as a valley. Therefore, in order to reduce the influence of respiratory arrhythmia, the average of pulsation intervals in a predetermined short time (time X) is used. Since the breathing cycle is about 4 seconds, the predetermined short time is preferably 4 to 8 seconds. The average of any of the beat intervals described above can be obtained as follows.

That is, the method of obtaining the average R bar (t) of the beat intervals at the time t may be a simple average, and the time series of the beat intervals is R(t _i ) and the average time is T.

Can be adopted. Here, the index i represents the number of the measured time, and t _i is the time of the measured number i. Further, n(t,T) represents the number of pulsation intervals measured from time t−T to time t. Alternatively, a weighted average using a one-sided Gaussian distribution may be used. In this case, the average beat interval R bar (t) at time t is

, The smoother average beat interval R bar (t) is obtained. In FIG. 6, the average of pulsation intervals in a predetermined short time and the short-term average pulsation interval SR are obtained by using the equation (1) with T=5 s, and the average and long pulsation intervals in a predetermined long time are calculated. The time-averaged beating interval LR is shown using equation (1) with T=60 s.

In the "deep valley" of the beat interval caused by apnea, the difference between the short-term average beat interval SR and the long-term average beat interval LR is smaller than a predetermined value V (valley depth threshold value V) SR. It is a part of −LR<V. By the way, the fluctuation of the beat interval is small when the heart rate is large (when the average beat interval is small), and is large when the heart rate is small (when the average beat interval is large). Therefore, the predetermined value V for determining the “deep valley” may be a function V=V(LR) that changes according to the average LR of the beat intervals for a long time. As the function V(LR), for example, V(LR)=αLR or V(LR)=αLR ² with α being a constant can be adopted.

In FIG. 6, V(LR)=−0.00009LR ² , and two valleys A and B are detected. Furthermore, even a valley searched by SR-LR<V may be a sudden valley caused by REM sleep. In order to avoid this, when the data of the beat interval included in SR-LR<V is continuous for a predetermined number Q (valley determination threshold value Q) or more, the "deep valley" caused by the apnea condition Judge as a candidate. The predetermined number Q is preferably 2 or more because it does not detect a sudden valley. At points A and B in FIG. 6, two or more beat interval data (SR-LR time series) are continuously included. Finally, the CVHR, which is a feature of SAS, is that the pulsation intervals increase and decrease periodically, so within a predetermined judgment time, a "deep valley" equal to or greater than a predetermined number P (abnormal valley number threshold P) is reached. It is sufficient to determine that the apnea state is detected. The predetermined determination time is preferably 120 seconds or more because the CVHR cycle is about 25 seconds to 120 seconds. The predetermined number P is preferably 2 or more because it is desired to check whether the "deep valley" is repeated. In FIG. 6, there are two “deep valleys”, A and B, within 120 seconds, and it can be determined to be apnea.

FIG. 2 shows another example 1 of this embodiment.

Subjects with Obstructive Sleep Apnea Syndrome (OSAS) do not have apnea when sleeping in the lateral or prone position. Therefore, if it is possible to detect whether or not the posture of the subject is in the supine position, it is possible to configure an apnea detection system with fewer false detections.

Another example 1 shown in FIG. 2 is obtained by the posture measuring means 19 for measuring the pulsation interval and at the same time the posture of the target person in the apnea detection system 1 of FIG. 1, and the posture measuring means 19. Based on the posture, the posture determining means 23 for determining whether the patient is standing, lying down or lying down, and the posture state obtained by the posture determining means 23 from the time series of the pulsation intervals measured by the pulsation interval measuring means 4 (position Based on the information), either the standing position, the prone position or the lateral position, or the pulsation interval in the standing position, the prone position and the lateral position (when not in the supine position) is excluded, and the pulsation interval. And a predetermined posture pulsation interval excluding means 24 for transferring the time series of the pulsation intervals after exclusion to the short-term average pulsation interval calculation means 8 and the long-term average pulsation interval calculation means 9. Is.

Specifically, in the sensor 2 shown in FIG. 2, a posture measuring unit 19, a posture storing unit 20, and a posture transmitting unit 21 are added to the sensor 2 of this embodiment (FIG. 1). Further, a posture receiving means 22, a body posture determining means 23 and a predetermined body posture pulsation interval excluding means 24 are added to the analyzer 3 of FIG.

The posture measuring means 19 of the sensor 2 is a device capable of measuring the posture of the target person, and for example, a three-axis acceleration sensor of MEMS can be used. Since such a sensor is lightweight, small in size, and has low power consumption, the burden on the subject is small.

The posture data measured by the posture measuring unit 19 is sequentially transferred to the posture storing unit 20 and temporarily stored. The posture storing means 20 may be common with the beat interval storing means 5 in order to make the sensor 2 lightweight, compact, and low in power consumption.

The posture data temporarily stored in the posture storing means 20 is transferred to the posture transmitting means 21. This transfer path may be the same as the transfer path of the beat interval storing means 5 and the beat interval transmitting means 6 in order to make the sensor 2 lightweight, compact, and low in power consumption.

The posture transmitting means 21 receives the posture data transferred from the posture storing means 20, and transfers the posture data to the posture receiving means 22 provided in the analyzer 3. In order to make the sensor 2 lightweight, small, and low in power consumption, the posture transmitting means 21 and the beat interval transmitting means 6 may be integrated, and the posture receiving means 22 and the beat interval receiving means 7 may be integrated. At this time, the transfer path from the attitude transmitting means 21 to the attitude receiving means 22 is common with the transfer path from the beat interval transmitting means 6 to the beat interval receiving means 7.

The posture data received by the posture receiving means 22 is transferred to the body position determining means 23. The posture determining means 23 determines whether or not the subject is sleeping in the supine position. For example, the posture measuring means 19 is composed of a triaxial acceleration sensor that is sensitive to gravity, and outputs the x-, y-, and z-axes of the subject from right to left, from the subject's feet to the head, and from the subject. The output values are (A _x , A _y , A _z ) by making them match from the chest to the back. If the subject is in a supine position, the gravitational acceleration is close to 0 in the direction from the subject's foot to head,

Meet Whether the subject is in the supine position or not can be determined from the angle at which the combined vector of A _x and A _z faces. The angle θ of the composite vector

As

If so, it can be determined to be supine. In other words, if you satisfy Eqs. (3) and (5), you are in a supine position.

As described above, the posture determining means 23 determines whether the posture data is in the supine position or not, and transfers the determination result to the predetermined posture pulsation interval excluding means 24.

The predetermined posture pulsation interval excluding means 24 receives whether or not the posture data is in the supine position from the posture determining means 23, receives the pulsation interval data from the pulsation interval receiving means 7, and determines the posture of the subject from the pulsation interval data. The pulsation intervals in the non-supine position are excluded, and the excluded pulsation interval data is transferred to the short-time average pulsation interval calculating means 8 and the long-time average pulsation interval calculating means 9.

Therefore, in the other example 1, it becomes possible to realize the apnea state detection system with less erroneous detection.

FIG. 3 shows another example 2 of this embodiment.

When the subject has a large body movement such as rolling over, the pulsation interval greatly increases or decreases. FIG. 7 shows changes in pulsation intervals caused by the subject's turning over and the magnitude of body movements. The horizontal axis represents time, the left vertical axis represents body movements, and the right vertical axis represents pulsation intervals. Here, the magnitude of body movement is expressed in a unit where the gravitational acceleration is 1 G. When rolling over occurs (indicated by P in FIG. 7), the body movement exceeds 0.3 G, and at the same time, the beat interval, which was about 1000 ms, is reduced to about 700 ms. Such changes in beat intervals closely resemble the changes in beat intervals that occur in CVHR. By excluding the pulsation intervals during large body movements, it is possible to configure an apnea detection system with few false detections.

Another example 2 shown in FIG. 3 is obtained from the apnea state detection system 1 shown in FIG. 1 by the posture measuring means 19 for measuring the pulsation interval and at the same time the posture of the subject, and the posture measuring means. From the body movement detecting means 25 for detecting body movement from the time series of posture, and the time series of the heartbeat intervals measured by the heartbeat interval measuring means 4, the body movement detected by the body motion detecting means 25 occurs. Body movements in which the beat intervals before and after a predetermined time from the time are excluded and the time series of the beat intervals after exclusion are transferred to the short-time average beat interval calculation means 8 and the long-time average beat interval calculation means 9. The time pulsation interval excluding means 26 is provided.

Specifically, the sensor 2 is the same as that of the another example 1 (FIG. 2), and the analyzer 3 is different from the analyzer 3 of FIG. 1 in that the posture receiving means 22, the body movement detecting means 25, and the body movement detecting means A beat interval excluding means 26 is added.

The posture measuring means 19 of the sensor 2 is a device capable of measuring the body movement of the subject, and it is preferable to use, for example, a MEMS triaxial acceleration sensor. Since such a sensor is lightweight, small in size, and has low power consumption, the burden on the subject is small.

The posture data measured by the posture measuring means 19 of the sensor 2 is transferred to the posture receiving means 22 of the analyzer 3 through the posture storing means 20 and the posture transmitting means 21.

The posture data received by the posture receiving means 22 of the analyzer 3 is transferred to the body movement detecting means 25.

The body movement detecting means 25 searches the posture data for the presence or absence of body movement. When the subject is turning over, for example, the subject accelerates. If the sensor 2 is always in close contact with the target person, the posture measuring means 19 can detect the acceleration associated with turning over. The attitude measuring means 19 is composed of a triaxial acceleration sensor, and outputs of the x, y, and z axes are (A _x , A _y , A _z ), respectively, and the acceleration sensor in a stationary state detects only gravity. _{Using x} ² +A _y ² +A _z ² )=1,

It is defined as. As can be seen from FIG. 7, if M is larger than a predetermined value, it can be determined that there is body movement. The predetermined value referred to here is preferably 0.1 to 0.3. The body movement detecting means 25 thus detects the presence or absence of body movement, and transfers the result to the body movement beat interval excluding means 26.

The beat interval excluding means 26 during body movement receives the presence/absence of body movement from the body movement detecting means 25, receives the beat duration data from the beat duration receiving means 7, and detects the time before and after the time when the body movement is present. Exclude beat interval data at time. This is because the pulsation interval fluctuates for a certain period of time before and after body movement. The predetermined time referred to here is preferably 60 seconds or more. The pulsation interval excluding means for body movement 26 excludes pulsation intervals relating to body movement, and then transfers the pulsation interval data to the short-time average pulsation interval calculation procedure 8 and the long-time average pulsation interval calculation means 9.

Therefore, in the second example, an apnea detection system with less erroneous detection can be realized.

FIG. 4 is another example 3 having both the configurations of the first example and the second example.

The sensor 2 of another example (or another example 2), the analyzer 3 in FIG. 1, the posture receiving means 22, the body posture determining means 23, the predetermined body posture pulsation interval excluding means 24, the body movement detecting means 25, and the body movement time beat. The apnea detection system 1 with less erroneous detection can be configured by using the one including the motion interval excluding means 26.

The order of the predetermined body position pulsation interval excluding means 24 and the body movement pulsation interval excluding means 26 of the analyzer 3 (the order of excluding the pulsation intervals) may be replaced with each other.

Since the present embodiment is configured as described above, it becomes a practical one in which the characteristic of CVHR can be detected from the pulsation interval by a simple calculation to grasp the presence or absence of an apnea condition.

1 Apnea State Detection System 3 Analyzer 4 Beat Interval Measuring Means 8 Short Time Average Beat Interval Calculation Means 9 Long Time Average Beat Interval Calculation Means
10 beat interval valley calculation means
11 Beat interval valley judgment means
14 Predetermined judgment time Uchidani count integration means
16 Valley comparison means
19 Attitude measuring means
23 Position determination means
24 Predetermined posture beat interval excluding means
25 Body movement detection means
26 Means for excluding beat intervals during body movement

Claims (8)

An apnea state detection system for detecting an apnea state of a subject, comprising a beat interval measuring means for measuring a beat interval of a subject's heart, and a beat interval measured by the beat interval measuring means. A short-time average pulsation interval calculating means for calculating a short-time average pulsation interval averaged over a predetermined time X such as a breathing cycle, and a long-time average pulsation averaged over a predetermined time Y longer than the time X. Long-time average beat interval calculating means, beat interval valley calculating means for calculating the difference between the short-time average beat interval and the long-time average beat interval, and beat interval valley calculating means In the time series of the difference between the short-time average pulsation interval and the long-time average pulsation interval obtained in step 1, a point where a value smaller than a predetermined valley depth threshold V exists is one beat. A beat interval valley determining means for determining a motion interval valley, and a predetermined determination time inner valley number integrating means for integrating the number of beat interval valleys determined by the beat interval valley determining means within a predetermined determination time, The number of pulsation interval valleys accumulated by the valley number accumulating means within the predetermined determination time is compared with a predetermined abnormal valley number threshold P, and if the number of pulsation interval valleys is the abnormal valley number threshold P or more, an apnea state. An apnea detection system comprising: a valley number comparing means for determining that The apnea detection system according to claim 1, wherein the pulsation interval valley determination means is configured to detect the valley depth threshold value in a time series of a difference between the short-time average pulsation interval and the long-time average pulsation interval. An apnea detection system characterized in that a value smaller than V is continuously judged to be a predetermined valley judgment threshold value Q or more as one beat interval valley. The apnea detection system according to any one of claims 1 and 2, wherein the posture measuring means for measuring the posture of the subject and whether the posture obtained from the posture measuring means is standing, prone or lying down. From the time series of the pulsation intervals measured by the pulsation interval measuring means, based on the position information obtained by the physiologic position determining means, either standing position, prone position or lateral position. The pulsation intervals in the body position are excluded, and the time series of the pulsation intervals excluding the pulsation intervals is transferred to the short-time average beat interval calculation means and the long-time average beat interval calculation means. An apnea state detection system, comprising: predetermined body position pulsation interval excluding means. The apnea detection system according to any one of claims 1 and 2, wherein a posture measuring unit that measures the posture of the target person, and a body that detects body movement from a time series of postures obtained from the posture measuring unit. From the time series of the pulsation intervals measured by the motion detection means and the pulsation interval measurement means, exclude pulsation intervals before and after a predetermined time from the time when the body motion detected by the body motion detection means occurs. And a beat interval excluding means for body movement for transferring the time series of the beat intervals excluding the beat intervals to the short-time average beat interval calculating means and the long-time average beat interval calculating means. An apnea detection system characterized by being provided. In the apnea detection system according to any one of claims 1 and 2, a posture measuring means for measuring the posture of the subject,
From the posture obtained from the posture measuring means, a posture determining means for determining whether the posture is prone or prone or lying down, and from the time series of the pulsation intervals measured by the pulsation interval measuring means, by the posture determining means. Based on the obtained posture information, the pulsation interval in any of the standing, prone or lateral postures is excluded, and the time series of the pulsation intervals excluding the pulsation interval is set to the short time. An average pulsation interval calculating means and a predetermined posture pulsation interval excluding means for transferring to the long-term average pulsation interval calculating means;
The body movement detecting means for detecting body movement from the time series of postures obtained from the posture measuring means, and the time series of the pulsation intervals measured by the pulsation interval measuring means are detected by the body movement detecting means. The pulsation intervals before and after a predetermined time from the time when the body movement occurred are excluded, and the time series of the pulsation intervals excluding the pulsation intervals is used as the short-time average beat interval calculation means and the long time. An apnea detection system, characterized in that it comprises means for excluding pulsation intervals during body movement that are transferred to means for calculating average pulsation intervals. The apnea detection system according to any one of claims 1 to 5, wherein the valley depth threshold value V is a function of the long-term average pulsation interval calculated by the long-time average pulsation interval calculation means. An apnea detection system characterized by the above. A sleep and sleep providing system for eliminating sleep apnea of a subject to provide sleep, comprising a beat interval measuring means for measuring a beat interval of a subject's heart, and the beat measured by the beat interval measuring means. It was equipped with an analyzer that determines apnea from the motion interval, and a stimulating means that eliminates apnea and improves sleep by generating sound or vibration to slightly awaken the subject. A system that provides a good night's sleep. A sleep and sleep providing system for eliminating sleep apnea of a subject to provide sleep, comprising a beat interval measuring means for measuring a beat interval of a subject's heart, and the beat measured by the beat interval measuring means. A short-time average pulsation interval calculating means for calculating a short-time average pulsation interval averaged from a pulsation interval for a predetermined time X of a breathing cycle, and a long time averaged for a predetermined time Y longer than the time X. A long-time average beat interval calculating means for calculating an average beat interval, a beat interval valley calculating means for calculating a difference between the short-time average beat interval and the long-term average beat interval, and the beat interval In the time series of the difference between the short-time average pulsation interval and the long-time average pulsation interval obtained by the valley calculating means, a point having a value smaller than a predetermined valley depth threshold V exists 1 Beat interval gap valley determining means for determining the beat interval valleys, and integration of the number of valleys within a predetermined determination time for integrating the number of the beat interval valleys determined by the beat interval valley determining means within a predetermined determination time Means, and the number of pulsation interval valleys accumulated by the number of valleys within the predetermined determination time is compared with a predetermined abnormal valley number threshold P, and if the number of pulsation interval valleys is equal to or greater than the abnormal valley number threshold P. When the number-of-valleys comparing means for determining an apnea state and the number-of-valleys comparing means determines the state of apnea, a sound or a vibration is generated to slightly awaken the subject to change the apnea state. A sleep-restoration system, which is provided with a stimulating means for solving the problem and improving sleep.

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