JP2001061797A - Fall-asleep judgment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the fall-asleep time based on the change of a heart rate or a pulse rate. SOLUTION: This device is provided with a measurement part 1 for measuring the heart rate or the pulse rate per unit time and defining it as the biological information value of each time, a reference value setting part 2 for setting a reference value considerable as the biological information value at the time of being awake in rest based on the biological information value in the initial period of measurement, a threshold setting part 3 for setting a relatively small first threshold and a relatively large second threshold based on the reference value and also a fall-asleep time estimation part 4 for estimating the earlier time between the time at which the biological information value becomes less than the first threshold and the time at which a value less than the second threshold is continuously taken for the preset number of times as the fall-asleep time. Since time-based fluctuation is taken into consideration in the reduction tendency of the biological information value, fall-asleep is accurately detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sleep state determining apparatus for detecting a change in the state of sleep of a living body based on information on the activity of the living body relatively easily obtained, such as a heart rate or a pulse rate.

[0002]

2. Description of the Related Art By detecting the degree of mental relaxation of a human body and a change in sleep state, it is possible to provide appropriate stimulation to promote sleep onset or induce a deeper sleep state according to the state. On the other hand, as a device that detects changes in human condition, there is a polysomnogram that includes brain waves, eye movements, myoelectricity, and the like.This is a large-scale device that is used in laboratories, hospitals, and other places equipped with measurement equipment. However, it is not suitable for daily use such as health equipment, and it is desired to accurately detect a change in sleep state by a simple alternative to polysomnography.

[0003] Here, generally, the heartbeat signal is a human state, sleep / wake, rest / exercise, posture change, eating,
Furthermore, it is constantly changing due to emotion, mental relaxation, stress, etc., and when awake, the heart rate and pulse rate per unit time decrease as the degree of relaxation increases, and further decrease when falling asleep. Are known.

[0004] Based on such knowledge, it has been proposed to detect the sleep onset by measuring the heart rate and the pulse rate. Japanese Patent Application Laid-Open No. 63-82673 discloses an increase or decrease in the pulse rate after going to bed. Is indicated as an index.
Japanese Patent Publication No. -150047 discloses that an integral value per pulse wave is calculated by dividing an integral value of a pulse wave level by a pulse rate, and an increase or decrease of the integral value is used as an index.
Further, Japanese Patent Application Laid-Open No. 3-41926 discloses that a pulse rate or a respiratory rate at bedtime is regarded as a biological information value at the time of rest and awakening and is used as a reference value, and the biological information value is equal to or less than a predetermined threshold set based on the reference value. It is shown that the time when the sleep time is reached is taken to fall asleep.

[0005]

However, in the above-described conventional configuration in which the sleep onset is determined using the degree of decrease in the pulse rate as an index, there is a considerable individual difference in the coincidence rate with the actual change in sleep state, and the sleep polygraph However, there is a problem that the accuracy is considerably lower than that of

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide a sleep onset judging device which can accurately detect a sleep onset time based on a change in a heart rate or a pulse rate. .

[0007]

According to a first aspect of the present invention, there is provided a measuring unit for measuring a heart rate or a pulse rate per unit time and obtaining a biological information value at each time, A reference value setting unit that sets a reference value that can be regarded as a biological information value at the time of rest and awakening based on the information value, and a threshold setting that sets a relatively small first threshold and a relatively large second threshold based on the reference value And a time when the biological information value is less than the first threshold value or a time when the number of times that the biological information value is less than the second threshold value is set in advance is set to an earlier time. It is characterized by having a sleep onset time estimating unit for estimating sleep onset time. Since the temporal variation is incorporated into the decreasing tendency of the biological information value, it is possible to accurately detect falling asleep.

According to a second aspect of the present invention, there is provided a measuring unit which measures a heart rate or a pulse rate per unit time and obtains a biological information value at each time, and represents a time-series trend of the biological information value. A trend curve calculation unit that calculates a trend curve set as described above, an increment calculation unit that calculates the degree of increase in the biological information value at each of the measurement times, and the biological information within a certain time before each of the measurement times. A sleep time estimating unit for estimating a time when a combination of the increment of the biological information value and the degree of the fluctuation becomes equal to or less than a preset threshold as a sleep time. The feature is that it is. In order to incorporate the stability of the biological information value, it is possible to accurately detect falling asleep.

Further, the invention according to claim 3 is a measuring section which measures a heart rate or a pulse rate per unit time and obtains a biological information value at each time, and a living body at rest awakening based on the biological information value at the initial stage of measurement. A reference value setting unit that sets a reference value that can be regarded as an information value; a threshold setting unit that sets a relatively small first threshold value and a relatively large second threshold value based on the reference value; A trend curve calculation unit that calculates a trend curve set to represent the tendency of an average time change, an increment calculation unit that calculates an increase in the biological information value at each of the measurement times, A variability calculator for calculating the variability of the biometric information value within a certain period of time, and the number of times that the biometric information value has become less than the first threshold or a value less than the second threshold set in advance Continuously The sleep time estimating unit for estimating the earliest time as the sleep time during the time when the combination of the measured time or the increment of the biological information value and the degree of variation become equal to or less than the preset threshold value. Since it has a characteristic and incorporates temporal fluctuation into the decreasing tendency of the biological information value and also incorporates stability of the biological information value, falling asleep can be detected with higher accuracy.

With respect to the reference value calculated based on the biological information value at the initial stage of measurement, a reference value resetting unit for rewriting the reference value when the subsequent biological information value exceeds the reference value is provided. It is also preferable to use It is possible to accurately detect falling asleep regardless of the initial state of measurement.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an example of an embodiment. FIG. 1 shows a basic configuration of an example of the embodiment, wherein a measuring unit 1, a reference value setting unit 2, a threshold value It comprises a setting unit 3 and a sleep onset time estimation unit 4.

The measuring section 1 receives, for example, a heart rate signal from a heart rate sensor. After obtaining a pulse-like signal by performing waveform shaping, the number of pulses per unit time is counted.
Heart rate H per unit time (for example, 1 minute)
Output as (t).

The heart rate H (t) output from the measuring unit 1 is
The values are input to a reference value setting unit 2 and a sleep onset time estimation unit 4 for setting a reference value that can be regarded as a biological information value when the user is awake.

The reference value setting unit 2 calculates, as a reference value, a reference heart rate Hr that can be regarded as a heart rate at the time of rest and awakening. As shown in FIG. 2, the heart rate H (t) output from the measurement unit 1 is calculated. ) Are averaged, and the result is adopted as the reference value Hr. However, the previous heart rate H (t-1)
If the heart rate H (t) is greater than 5 this time, it is assumed that noise due to body motion etc. has entered, and the value of the current heart rate H (t) is the same as the value of the previous heart rate H (t-1). Using the reference value H
r is calculated.

Reference value Hr output from reference value setting unit 2
Is input to the threshold setting unit 3. The threshold setting unit 3 sets a value of 80% to 95% with respect to the input reference value Hr as the first threshold and the second threshold.
It is assumed that the second threshold value is larger than the threshold value (for example, 93% is the first threshold value and 95% is the second threshold value).

The sleep onset determination is performed by the sleep onset time estimating unit 4.
This is performed using the number of pulses input from the measuring unit 1 every minute and two thresholds input from the threshold setting unit 3. That is, as shown in FIG. 3, the falling-on time estimating unit 4 compares the input heart rate H (t) with the first threshold value, and if it is smaller than the first threshold value, estimates that it is falling asleep. If the value is larger than the first threshold value, the heart rate H (t) is compared with the second threshold value. If the value is smaller than the second threshold value, the variable Hs is increased by one. Next, it is determined whether or not the variable Hs is equal to or greater than a preset number (for example, 4). If the variable Hs is equal to or greater than the preset number, it is determined that the user falls asleep. If the number is less than the preset number, the same analysis is repeated based on the next input heart rate H (t + 1), and the heart rate H
When (x) becomes smaller than the first threshold value or when the variable Hs becomes equal to or more than a preset number, it is determined that the user falls asleep.

FIG. 4 shows another example. The heart rate H (t) output from the measuring unit 1 is calculated by using a trend curve calculating unit 5 that calculates a trend curve set so as to indicate the tendency of the time series change of the biological information value, and the biological information at each measurement time. The values are input to an increment calculator 6 that calculates the degree of increase in the value and a degree-of-variation calculator 7 that calculates the degree of fluctuation of the biological information value within a certain period of time before each measurement time.

The trend curve calculating section 5 calculates a trend curve set so as to represent the average time-varying trend of the biological information value. That is, the trend curve calculation unit 5 calculates the trend curve FT (t) from the input heart rate H (t) as shown in FIG.

When t = 1 FT (1) = H (1) When t> 1 and when H (t) ≧ FT (t−1), FT (t) = FT (t−1) When t> 1 And when H (t) <FT (t-1) FT (t) = H (t) An example of the trend curve FT (t) thus obtained is shown in FIG. In the figure, the thin line A indicates the heart rate, and the thick line B indicates the trend curve FT (t).

The trend curve FT (t) output from the trend curve calculation section 5 is input to an increment calculation section 6 for calculating the degree of increase of the biological information value at each measurement time. In the increment calculation unit 6, an increment ZOU (t) (ZOU (t) = H (t)-), which is an index indicating the degree of increase of the heart rate H (t) from the trend curve FT (t).
FT (t)) is calculated. FIG. 7 shows an example of the increment ZOU (t).

The variability calculator 7 calculates the variability of the heart rate H (t) input from the measuring unit 1. First,
The absolute value of the difference between the heart rate H (t) and the heart rate H (t-1) one minute ago (referred to as a difference SABUN (t)) is calculated. The difference SABUN (t) is | (H (t) −H (t−1) | <6. SABUN (t) = | (H (t) −H (t−1) || (H (t ) −H (t−1) | ≧ 6 SABUN (t) = 6.

Further, using the difference SABUN (t),
When BARA (t) is t = 1 BARA (1) = SABUN (1) When t = 2 BARA (2) = SABUN (1) + SABUN (2) When t = 3 BARA (3) = SABUN (1 ) + SABUN (2) + SABUN (3) When t = 4 BARA (4) = SABUN (1) + SABUN (2) + SABUN (3) + SABUN (4) When t ≧ 5 BARA (t) = SABUN (t-4 ) + SABUN (t-3) + SABUN (t-2) + SABUN
Calculate as (t-1) + SABUN (t). Variation degree BARA obtained in this way
FIG. 8 shows an example of (t).

The sleep onset estimation by the sleep onset time estimating section 4 is performed by setting the increment ZOU (t) and the variation BARA (t) inputted every minute from the increment calculating section 6 and the variation calculating section 7 and presetting them. This is performed by comparing with a threshold value. That is, in the sleep onset time estimation unit 5, both the increment ZOU (t) and the variation BARA (t) are preset thresholds (for example, the increment ZOU (t) is 3 and the variation BARA (t) is 7). If it becomes smaller, it is estimated that it falls asleep.

FIG. 9 shows still another example. The measurement unit 1 in the figure,
The reference value setting section 2, threshold value setting section 3, trend curve calculation section 5, increment calculation section 6, and variation degree calculation section 7 are the same as those in the above two examples.

The sleep onset estimation is performed by a sleep onset time estimating unit 4 in which the heart rate H (t) inputted from the measuring unit 1 every minute is represented by:
This is first performed using the first threshold and the second threshold input from the threshold setting unit 3. That is, the sleep onset time estimation unit 4 compares the input heart rate H (t) with the first threshold as shown in FIG. If the heart rate H (t) is larger than the first threshold value, the heart rate H (t) is compared with the second threshold value. If the heart rate H (t) is smaller than the second threshold value, the variable Hs is increased by 1 and the variable Hs is equal to or more than a preset number (for example, 4). It is determined whether or not it falls asleep if the number is equal to or greater than a preset number. If it is less than the preset number, repeat the same analysis based on the next input heart rate H (t + 1),
Either the heart rate H (x) is smaller than the first threshold value, the variable Hs is equal to or greater than a preset number, or both the increment ZOU (t) and the variation BARA (t) are preset. If the threshold value (for example, the increment ZOU (t) is 3 and the degree of variation (BARA (t)) is smaller than 7), it is estimated that the user falls asleep.

FIG. 11 shows another example. This shows that a reference value resetting unit 8 for correcting the reference value Hr obtained by the reference value setting unit 2 to a more appropriate value is provided, and the heart rate H (t) output from the measuring unit 1 is shown. Is a reference value setting unit 2 that sets a reference value that can be regarded as a biological information value at the time of rest and awakening,
The reference value is input to the reference value resetting unit 8 for resetting the reference value depending on the initial state of the living body. As described above, the reference value setting unit 2 averages the first three values of the heart rate H (t) to obtain the reference value Hr.
Set.

On the other hand, as shown in FIG. 12, a reference value resetting unit 8 calculates a value Hp obtained by averaging three consecutive values from the heart rate H (t) output from the measuring unit 1 and a reference value setting unit. Then, the new average value Hp is compared with the reference value Hr, and if the new average value Hp is larger than the reference value Hr, the value of the new average value Hp is substituted for the reference value Hr. The new reference value Hr is input to the threshold setting unit 4, a new first threshold and a new second threshold are set, and the sleep onset time estimation unit 4 determines sleep on the basis of these values. In this case, it is possible to accurately estimate the sleep onset time even when the heart rate increases after that as compared to the average of the heart rate for three minutes from the start of the measurement.

In each of the above examples, the heart rate is used as the biological information value as an index of the activity state of the living body. However, the same processing can be performed with the pulse rate.

[0029]

As described above, according to the first aspect of the present invention, a reference value setting unit for setting a reference value that can be regarded as a biological information value at the time of rest and awakening based on the biological information value at the initial stage of measurement; A threshold setting unit that sets a relatively small first threshold and a relatively large second threshold based on the threshold value, and presets a time at which the biological information value falls below the first threshold or a value less than the second threshold. It is provided with a sleep onset time estimating unit for estimating an earlier time as a sleep onset time among the times when the number of times set in succession is taken. From the determination, falling asleep can be detected with high accuracy.

Further, according to the invention of claim 2, a trend curve calculating section for calculating a trend curve set so as to represent a tendency of an average time change of the time series of the biological information value; An increment calculator for calculating the increment of the information value, a variability calculator for calculating the variance of the biological information value within a certain time period before each of the measurement times, and a combination of the increment and the variability of the biological information value Is provided with a sleep onset time estimating unit for estimating the time at which the time becomes equal to or less than a preset threshold as a sleep onset time, in this case, the stability of the biological information value is incorporated, Therefore, falling asleep can be accurately detected.

According to the third aspect of the present invention, since the stability is incorporated into the decreasing tendency and the temporal variation of the biological information value, it is possible to accurately detect falling asleep.

According to the fourth aspect of the present invention, after the reference value calculated based on the biological information value at the initial stage of the measurement is determined, the reference value is rewritten when the biological information value exceeds the reference value. Therefore, falling asleep can be accurately detected regardless of the initial state of the living body.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram of an example of an embodiment of the present invention.

FIG. 2 is a flowchart showing processing contents of a reference value setting unit according to the first embodiment;

FIG. 3 is a flowchart showing processing contents of a sleep onset time estimating unit according to the embodiment.

FIG. 4 is a block circuit diagram of another example.

FIG. 5 is a flowchart showing processing contents of a trend curve calculation unit according to the embodiment.

FIG. 6 is a graph showing an example of the above trend curve.

FIG. 7 is a graph showing an example of the above increment.

FIG. 8 is a graph showing an example of a variation degree according to the embodiment.

FIG. 9 is a block circuit diagram of still another example.

FIG. 10 is a flowchart showing a processing content of a sleep onset time estimating unit according to the embodiment.

FIG. 11 is a block circuit diagram of another example.

FIG. 12 is a flowchart showing a processing content of a reference value resetting unit according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measurement part 2 Reference value setting part 3 Threshold setting part 4 Sleeping time estimation part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiro Michimori 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works, Ltd. (72) Inventor Kei Hagiwara 1048 Kadoma Kadoma, Osaka Prefecture F-term in Matsushita Electric Works Co., Ltd. (reference) 4C017 AA02 AA10 4C038 PP05 PQ00 PS00

Claims (4)

[Claims] 1. A measuring unit that measures a heart rate or a pulse rate per unit time and obtains a biological information value at each time, and a reference value that can be regarded as a biological information value at the time of rest and awakening based on the biological information value at the beginning of measurement. And a threshold value setting unit that sets a relatively small first threshold value and a relatively large second threshold value based on the reference value, and the biological information value is less than the first threshold value. A sleep onset time estimating unit for estimating an earlier time as a sleep onset time among times in which the number of consecutive times or a value less than the second threshold value is preset. Sleep detection device. 2. A measuring unit that measures a heart rate or a pulse rate per unit time and obtains a biological information value at each time, and a trend curve set so as to represent a tendency of a time series of the biological information value over time. A trend curve calculating unit for calculating, an increment calculating unit for calculating an increasing degree of the biological information value at each of the measurement times, and calculating a variation degree of the biological information value within a fixed time before each of the measuring times. A degree-of-variation calculating section, and a sleep-onset time estimating section for estimating a sleep-onset time at a time when a combination of the increment of the biometric information value and the degree of variance becomes equal to or less than a preset threshold. Sleep detection device. 3. A measuring unit that measures a heart rate or a pulse rate per unit time and obtains a biological information value at each time, and a reference value that can be regarded as a biological information value at the time of rest and awakening based on the biological information value at the initial stage of measurement. A threshold value setting unit that sets a relatively small first threshold value and a relatively large second threshold value based on the reference value, and a time-series average time change of the biological information value. A trend curve calculation unit that calculates a trend curve set to represent the trend, and an increment calculation unit that calculates an increase in the biological information value at each of the measurement times,
A variation calculation unit that calculates the variation of the biological information value within a certain time period before each of the measurement times; and a time when the biological information value falls below the first threshold or the second
Of the times when the number of times less than the threshold value is set in advance, or the time when the combination of the increment of the biometric information value and the degree of variation becomes equal to or less than the preset threshold value, the earliest time is the sleep time. A sleep onset determining unit for estimating sleep onset. 4. A reference value resetting unit for rewriting a reference value calculated based on a biological information value at an initial stage of measurement when the subsequent biological information value exceeds the reference value. The sleep onset judging device according to claim 1 or 3, wherein: