Sleep/wake decision system
阅读说明:本技术 睡眠/觉醒判定系统 (Sleep/wake decision system ) 是由 轰真佑 矶野史朗 饭田德仁 于 2019-03-13 设计创作,主要内容包括:本发明涉及睡眠/觉醒判定系统(100),判定床(BD)上的受检者处于睡眠状态以及觉醒状态中的哪一种状态,具备:负荷检测器(11),检测上述床上的上述受检者的负荷;以及判定部(33),基于对上述受检者的负荷的随时间的变动的标准偏差进行时间积分而得到的值与阈值的比较,来判定上述受检者处于睡眠状态以及觉醒状态中的哪一种状态。(The present invention relates to a sleep/wake determination system (100) for determining which of a sleep state and a wake state a subject on a Bed (BD) is in, the sleep/wake determination system including: a load detector (11) for detecting the load of the subject on the bed; and a determination unit (33) that determines whether the subject is in the sleep state or the awake state based on a comparison between a value obtained by time-integrating a standard deviation of a temporal variation in the load of the subject and a threshold value.)
1. A sleep/wake determination system for determining which of a sleep state and a wake state a subject in bed is in, the sleep/wake determination system comprising:
a load detector for detecting a load of the subject on the bed; and
and a determination unit that determines which of the sleep state and the awake state the subject is in, based on a comparison between a value obtained by time-integrating a standard deviation of a temporal variation in the load of the subject and a threshold value.
2. The sleep/wake determination system as claimed in claim 1, wherein,
the sleep/wake determination system further includes a respiratory waveform acquisition unit that obtains a respiratory waveform of the subject based on a temporal change in a load of the subject,
the determination unit determines which of a sleep state and an awake state the subject is in, based on a comparison between a value obtained by time-integrating a value obtained by dividing the amplitude of the respiration waveform by the standard deviation and a threshold value.
3. The sleep/wake determination system as claimed in claim 1 or 2, wherein,
the load detector at least comprises a 1 st load detector and a 2 nd load detector,
the standard deviation is a simple average of a 1 st standard deviation of a temporal variation in the load of the subject detected by the 1 st load detector and a 2 nd standard deviation of a temporal variation in the load of the subject detected by the 2 nd load detector.
4. The sleep/wake determination system as claimed in claim 3, wherein,
the load detector further includes a 3 rd load detector and a 4 th load detector,
The standard deviation is a simple average of a 1 st standard deviation of temporal variation in the load of the subject detected by the 1 st load detector, a 2 nd standard deviation of temporal variation in the load of the subject detected by the 2 nd load detector, a 3 rd standard deviation of temporal variation in the load of the subject detected by the 3 rd load detector, and a 4 th standard deviation of temporal variation in the load of the subject detected by the 4 th load detector.
5. The sleep/wake determination system as claimed in claim 1 or 2, wherein,
the load detector at least comprises a 1 st load detector and a 2 nd load detector,
the standard deviation is a series of values obtained by sequentially selecting, at each time, the greater one of the 1 st standard deviation of the temporal fluctuation in the load of the subject detected by the 1 st load detector and the 2 nd standard deviation of the temporal fluctuation in the load of the subject detected by the 2 nd load detector.
6. A bed system is provided with:
a bed; and
the sleep/wake decision system as claimed in any one of claims 1 to 5.
Technical Field
The present invention relates to a sleep/wake determination system that performs sleep/wake determination of a subject based on a detection value of a load detector.
Background
In the field of medical care and nursing care, it is proposed to detect a load of a subject on a bed via a load detector and determine a state of the subject based on the detected load. Specifically, for example, it is proposed to determine which of the sleep state and the awake state of the subject, i.e., sleep/awake determination, is performed based on the detected load of the subject.
Patent document 1 discloses a sleep determination device as follows: the number of physical activities of the person on the bed, that is, the number of times of physical activities, is calculated based on the detection result of the load detection unit, and it is determined that the subject is in a sleeping state based on the calculated number of physical activities.
Patent document 1: japanese patent laid-open publication No. 2016 + 123810.
Disclosure of Invention
The invention aims to provide a sleep/wake determination system capable of performing sleep/wake determination of a subject with high accuracy.
According to the 1 st aspect of the present invention, there is provided a sleep/wake determination system for determining whether a subject in bed is in a sleep state or an awake state, the sleep/wake determination system including:
a load detector for detecting a load of the subject on the bed; and
and a determination unit that determines which of the sleep state and the awake state the subject is in, based on a comparison between a value obtained by time-integrating a standard deviation of a temporal variation in the load of the subject and a threshold value.
The sleep/wake determination system according to claim 1 may further include a respiratory waveform acquisition unit that obtains a respiratory waveform of the subject based on a temporal variation in the load of the subject, and the determination unit may determine which of the sleep state and the wake state the subject is in based on a comparison between a value obtained by dividing the amplitude of the respiratory waveform by the standard deviation and a threshold value, and a threshold value.
In the sleep/wake determination system according to claim 1, the load detector may include at least a 1 st load detector and a 2 nd load detector, and the standard deviation may be a simple average of a 1 st standard deviation of temporal fluctuation of the load of the subject detected by the 1 st load detector and a 2 nd standard deviation of temporal fluctuation of the load of the subject detected by the 2 nd load detector.
In the sleep/wake determination system according to claim 1, the load detector may further include a 3 rd load detector and a 4 th load detector, and the standard deviation may be a simple average of a 1 st standard deviation of temporal fluctuation of the load of the subject detected by the 1 st load detector, a 2 nd standard deviation of temporal fluctuation of the load of the subject detected by the 2 nd load detector, a 3 rd standard deviation of temporal fluctuation of the load of the subject detected by the 3 rd load detector, and a 4 th standard deviation of temporal fluctuation of the load of the subject detected by the 4 th load detector.
In the sleep/wake determination system according to claim 1, the load detector may include at least a 1 st load detector and a 2 nd load detector, and the standard deviation may be a series of values in which one of a 1 st standard deviation of temporal fluctuation of the load of the subject detected by the 1 st load detector and a 2 nd standard deviation of temporal fluctuation of the load of the subject detected by the 2 nd load detector is larger is selected in order at each time.
According to the 2 nd aspect of the present invention, there is provided a bed system comprising:
a bed; and
the sleep/wake determination system according to claim 1.
According to the sleep/wake determination system of the present invention, it is possible to perform sleep/wake determination of a subject with high accuracy.
Drawings
Fig. 1 is a block diagram showing a configuration of a sleep/wake determination system according to an embodiment of the present invention.
Fig. 2 is an explanatory diagram showing the arrangement of the load detector with respect to the bed.
Fig. 3 is a flow chart illustrating a method of sleep/wake determination using a sleep/wake determination system.
Fig. 4 is a schematic diagram showing changes in the load value detected by the load detector for both the quiet period in which the subject breathes only and the period in which the subject is performing physical activity.
Fig. 5 (a) is an explanatory view schematically showing a case where the center of gravity of the subject vibrates in the body axis direction of the subject according to the breathing of the subject. Fig. 5 (b) is a graph showing an example of a respiration waveform drawn based on the vibration of the center of gravity of the subject corresponding to the respiration of the subject.
Fig. 6 (a), 6 (b), 6 (c), 6 (d), 6 (e) are graphs showing the relationship between the physical activity of the subject and the amount of increase in the activity index caused thereby, respectively. Fig. 6 (a) is a graph when the subject in sleep turns over, fig. 6 (b) is a graph when the subject in sleep makes twitches (twitches), fig. 6 (c) is a graph when the subject in sleep moves the right hand, fig. 6 (d) is a graph when the subject in wakefulness reads, and fig. 6 (e) is a graph when the subject in wakefulness has a meal.
Fig. 7 is a block diagram showing the overall configuration of the bed system according to the modification.
Detailed Description
< embodiment >
The sleep/awake determination system 100 (fig. 1) according to the embodiment of the present invention is described by taking as an example a case of determining whether the subject S on the bed BD is in the sleep state or the awake state by using the same together with the bed BD (fig. 2).
As shown in fig. 1, the sleep/
The load detection unit 1 includes 4
As shown in FIG. 2, the 4
The a/
The
The storage unit 4 is a storage device that stores data used in the sleep/
The
The input unit 6 is an interface for performing predetermined input to the
An operation of determining sleep/wake of a subject in bed using such a sleep/
The determination of sleep/wake of a subject using the sleep/
[ load detection Process ]
In the load detection step S1, the load of the subject S on the bed BD is detected using the
The
[ procedure for calculating Standard deviation ]
At standard deviation calculationIn step S2, the standard
The standard deviation represents the magnitude of the difference in the sample values, so as shown in fig. 4, the subject S on the bed BD is quiet and the load signal S 1~s4Period P with a small amount of fluctuation1Standard deviation σ1~σ4And also becomes smaller. On the other hand, the subject S moves the body (physical activity is generated in the subject S) and the load signal S1~s4Period P of large fluctuation2Standard deviation σ1~σ4And also becomes larger.
Therefore, during a period in which the subject S is physically moving, the standard deviation σ is larger than during a period in which the subject S is not physically moving (for example, during a period in which the subject S breathes without moving the body or the hands and feet)1~σ4The value of (a) is large.
Further, in the present specification and the present invention, "physical activity" includes "greater physical activity" and "smaller physical activity". The subject's body moves slightly due to the subject's breathing, heartbeat, but these are not included in "physical activity".
The large physical activity refers to a relatively large physical activity accompanied by movement of the body (trunk) of the subject, and specifically includes, for example, turning over, getting up, and the like. When a subject produces a large physical activity, in general, the orientation of the body axis of the subject (the orientation in which the spine of the subject extends) changes.
The small physical activity refers to a relatively small physical activity that is not accompanied by movement of the body (trunk) among the physical activities of the subject, and specifically, is, for example, a movement of only hands and feet, a head, or the like.
In general, the target in the case where the physical activity of the subject S is a large physical activityQuasi deviation sigma1~σ4Is smaller than the standard deviation sigma in the case where the physical activity of the subject S is smaller1~σ4The value of (2) is large.
[ respiratory waveform drawing step ]
In the respiratory waveform drawing step S3, the respiratory waveform drawing unit (respiratory waveform acquisition unit, respiratory waveform calculation unit) 32 calculates the respiratory waveform based on the load signal S1~s4A respiration waveform of the subject S is depicted.
Human breathing is performed by moving the chest and diaphragm to inflate and deflate the lungs. Here, during inspiration, i.e., when the lung is inflated, the diaphragm descends downward and the internal organs also move downward. On the other hand, during expiration, i.e., during lung contraction, the diaphragm rises upward, and the internal organs also move upward. As described in the specification of japanese patent No. 6105703, which is assigned to the applicant of the present invention, the center of gravity G slightly shifts with the movement of the viscera, and the shifting direction thereof is almost along the extending direction of the spine (body axis direction).
In the present invention and the present specification, the "respiration waveform" refers to a waveform in which the vibration of the center of gravity of a subject that vibrates in the body axis direction of the subject according to the respiration of the subject is developed and shown on the time axis. The 1 cycle of the respiratory waveform corresponds to 1 breath (expiration and inspiration) of the subject. The amplitude of the respiration waveform is affected by the physical constitution of the subject and the depth of respiration. Specifically, for example, the amplitude is increased when the subject is large in size or the subject breathes deeply, and the amplitude is decreased when the subject is small in size or the subject breathes shallowly.
The respiratory
The respiratory
Next, the respiration
The respiratory
[ sleep/wake determination procedure ]
In the sleep/wake determining step S4, the sleep/
The determination is specifically performed as follows.
The sleep/
Next, the sleep/
[ formula 1]
σsn=σn/A(n=1、2、3、4)
Such normalization is performed for the following reason.
As described above, the standard deviation σ1~σ4The value of (b) becomes large during the period in which the subject S generates physical activity. Here, the standard deviation σ1~σ4Showing the magnitude of the difference in the detection values of the
On the other hand, since the amplitude of the respiration waveform is affected by the physique of the subject S as described above, the amplitude An and the respiration waveform average amplitude a become large when the physique of the subject S is large, and the amplitude An and the respiration waveform average amplitude a become small when the physique of the subject S is small.
Thus, the standard deviation σ is used as shown in equation 11~σ4By normalizing the value of (a) by dividing the respiratory waveform average amplitude a, the body constitution (body characteristic) of the subject S can be reduced (compensated for) versus the standard deviation σ1~σ4The influence of the value of (c). Then, the normalized standard deviation σ s compensated for as described above is used1~σs4The accuracy of determination can be improved by performing sleep/wake determination on the subject S.
In addition, the standard deviation σ may be used instead of the average amplitude a of the respiration waveform1~σ4Is normalized by dividing the value of (a) by any of the amplitudes An obtained immediately before or this time.
Next, the sleep/
[ formula 2]
The integration time is 20 seconds here, but is not limited thereto as described later. Due to normalized standard deviation σ s1~σs4Increases according to the physical activity of the subject S, so in the case where the subject S shows the physical activity causing a large load change over a long time, the activity index ACI becomes large. Namely, the activity index ACI is a parameter that reflects both the magnitude of the physical activity and the duration (duration) of the physical activity.
In addition, in equation 2Normalized standard deviation σ s1~σs4The simple average of (c) is for the following reasons. I.e. normalized standard deviation σ s1~σs4The balance of the values of (a) varies depending on the position of the subject S on the bed BD, and for example, when the center of gravity G of the subject S is in the vicinity of the
The sleep/
The comparison of the activity index ACI with the threshold value is performed, for example, as follows.
As an example 1, when any of the latest 4 values of the activity index ACI calculated every 20 seconds exceeds a predetermined threshold, it is determined that the subject S is in an awake state. As an example 2, when the total value of the latest 3 values of the activity index ACI calculated every 20 seconds exceeds a predetermined threshold, it is determined that the subject S is in an awake state. In this way, by performing the determination not only using the latest activity index ACI but using a plurality of activity indexes ACI obtained in a certain time width, the accuracy of the determination can be further improved.
Here, the reason why the accuracy of determination can be improved by performing sleep/wake determination of the subject S using the activity index ACI will be described.
In general, a human shows a smaller amount of physical activity in sleep compared to the amount of physical activity shown in arousal. However, even during sleepIn some cases, a turn, a minute movement called twitch (called a twitch movement of a muscle occurring in rapid eye movement sleep) is shown. In addition, the posture may be changed by moving hands, feet, or the head. Therefore, even according to the normalized standard deviation σ s1~σs4The value of (a) is not necessarily sufficient, and the presence or absence of physical activity and the number of times of physical activity of the subject S are determined, and sleep/wake determination is performed only based on the presence or absence of physical activity and the number of times of physical activity.
In contrast, the activity index ACI is for the normalized standard deviation σ s1~σs4The value obtained by integrating the simple average of (a) and (b) with respect to time is the magnitude of the physical activity (normalized standard deviation σ s)1~σs4Magnitude of the increase) and duration of physical activity (normalized standard deviation σ s)1~σs4Length of the increased period).
Therefore, even when the subject S shows a relatively large physical activity during 20 seconds, the activity index ACI does not become a particularly large value when the duration of the physical activity is short. On the other hand, even in the case where the subject S does not exhibit a significantly large physical activity for a period of 20 seconds, the activity index ACI becomes a large value in the case where the subject S continuously shows a small physical activity.
A brief specific example is shown in fig. 6 (a) to 6 (e).
FIG. 6 (a) shows a normalized standard deviation σ S in the case where the subject S who is in a sleeping state during 20 seconds turns over1~σs4Simple average of (hereinafter, referred to as σ s)AV) A brief diagram of the variation of (2). The value of the activity index ACI corresponding to this period corresponds to the area of the hatched portion of the graph (the same applies to fig. 6 (b) to 6 (e)).
Fig. 6 (b) is a graph showing a simple average σ S in the case where the subject S in the sleep state during 20 seconds shows twitchingAVIn fig. 6, (c) is a schematic diagram showing the state of change in the time period of 20 secondsThe subject S in the sleeping state shows a simple average σ S in the case where there is little physical activity and the right hand is changed from the state of bending to the state of stretchingAVA brief diagram of the variation of (2).
Fig. 6 (d) shows the simple average σ S in the case of reading the subject S in the awake state for a period of 20 secondsAVFig. 6 (e) is a simple average σ S showing the case where the subject S in the awake state has a meal for 20 secondsAVA brief diagram of the variation of (2).
As read from fig. 6 (a) to 6 (e), the value of the activity index ACI tends to become a larger value in the case where the subject S in wakefulness shows continued physical activity. Therefore, by appropriately setting the threshold value used for determination, the influence of instantaneous physical activity determination such as turning over, twitching, and posture change of the subject S during sleep can be reduced, and sleep/wake determination with high accuracy can be performed.
[ display Process ]
In the display step S5, the determination result output by the control unit is displayed on the
The effects of the sleep/
The sleep/
The sleep/
The sleep/
[ modified examples ]
In the sleep/
In the sleep/
As an example, the normalization standard deviation σ s may be used in (equation 2) by the sleep/
[ formula 3]
The sleep/
The sleep/
The activity index ACI of these variations is also a parameter that reflects both the magnitude of the physical activity and the duration (duration) of the physical activity. Further, an arbitrary parameter obtained by time-integrating the standard deviation of the temporal fluctuation of the load of the subject and reflecting both the magnitude of the physical activity and the duration (duration) of the physical activity may be used as the activity index ACI.
In the explanation of the sleep/
In addition, in the calculation of the activity index ACI, a variance, which is a square of the standard deviation, may be used instead of the standard deviation. In the present specification and the present invention, a value obtained by integrating the square deviation with time is also included in the "value obtained by integrating the standard deviation with time".
The sleep/
The sleep/
The
In the sleep/
The present invention is not limited to the above-described embodiments as long as the features of the present invention are maintained, and other embodiments that can be considered within the scope of the technical idea of the present invention are also included in the scope of the present invention.
Industrial applicability
According to the sleep/wake determination system of the present invention, it is possible to perform sleep/wake determination of a subject with high accuracy, and it is possible to provide medical treatment and care with high quality based on the determination with high accuracy.
Description of reference numerals: a load detection portion; 11. 12, 13, 14. An A/D conversion section; a control section; a standard deviation calculation section; a respiratory waveform delineation section; a sleep/wake determination section; a storage portion; a display portion; an input portion; a sleep/wake decision system; BD.. bed; a bed system; a subject.
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