JPH105184A - Mental stress judging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To objectively judge a mental stress as a steady stress. SOLUTION: While alternately imparting a task and a rest as a temporary stress for a prescribed time to an examinee by a task/rest presenting unit 101, a beat signal as heartbeat corresponding data of the examinee is measured by a heartbeat corresponding data gathering unit 102, and is outputted to an RRI detecting circuit 103. The RRI detecting circuit 103 detects RRI data being its time interval from the heartbeat corresponding data, and outputs it to a sympathetic parasympathetic nerve activity calculating circuit 104, and a degree of dispersion of the RRI data is caculated by the sympathetic parasympathetic nerve activity calculating circuit 104, and data in a task condition and a rest condition is found as a distribution area on a two-dimensional plane. Therefore, a mental stress judging circuit 105 judges the existence of a mental stress from an overlapping condition of respective distribution areas of a task condition and a rest condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mental stress determination device for determining mental stress as a constant stress of a person.

[0002]

2. Description of the Related Art Conventionally, there is a stress level measuring apparatus for measuring a stress level of a person by measuring a fluctuation state of pulse data by a microcomputer. As shown in FIG. 24, a pulse wave detector 501 for detecting a subject's pulse wave is connected to a pulse counter 502, and the pulse counter 502 is connected to a microcomputer 503. Then, as shown in FIG. 25, the pulse wave data detected by the pulse wave
The pulse data is converted into a shaped pulse according to 2 and the pulse data is counted.
The level of the stress is measured by monitoring the data. A similar one is described in JP-A-4-180730.

[0003]

In recent years, people have been subjected to various stresses at work or in daily life. In particular, due to rapid OA (office automation) and FA (factory automation), VDT (video display terminal) work and monitoring work are increasing, and mental stress caused by these work is a cause of overwork and human error. I have. In order to prevent this, it is important to evaluate and determine mental stress (also called techno stress).

[0004] However, the conventional stress level measuring device is configured to use only information on the rise and fall of the heart rate, so that the reliability of the stress level measurement is low, and
There was a problem that only temporary stress at the time of measurement could be measured. As described above, at present, no technology has been established to objectively measure or quantitatively evaluate the amount of sensation of mental stress.

The present invention has been proposed to solve the above problems, and has as its object to provide a mental stress determination apparatus for objectively determining mental stress as stationary stress.

[0006]

In order to achieve the above object, a mental stress determining apparatus according to the present invention comprises a task presenting means for applying a temporary stress to a subject, and a heart rate equivalent for collecting heart rate equivalent data of the subject. A heartbeat interval detecting means for detecting a beat interval based on the heartbeat equivalent data collected by the heartbeat equivalent data collection means; and a sympathetic sense based on the beatinterval data detected by the beat interval detector. A device comprising a sympathetic parasympathetic activity calculating means for calculating parasympathetic activity, and a mental stress determining means for determining mental stress based on the sympathetic parasympathetic activity calculated by the sympathetic parasympathetic activity calculating device. did.

[0007] The above-mentioned mental stress judging means is based on the sympathetic and parasympathetic nervous activity of the same subject based on heartbeat-equivalent data collected at a plurality of different times. Is preferably determined. Further, it is preferable that the task presenting means uses a timer and presents time to the subject so that the task and the rest for a certain time are alternately performed.

Further, the task presentation means makes the subject input while controlling the execution speed by the computer such that the task is an input operation to the computer and the load of the added task falls within a predetermined range. It is preferred that In particular, an operation of sequentially displaying a plurality of targets on a display at a predetermined presentation speed, erasing the targets after a predetermined period of time, and superimposing a cursor on each target while each target is displayed and clicking the target is an input operation. It is desirable to change the presentation speed of the target according to the operation error amount for each set time.

The above-described sympathetic / parasympathetic nerve activity calculating means calculates a normalized variance and an average heart rate from the beat interval data detected by the beat interval detecting means, and calculates the normalized variance and the average heart rate. Are obtained as a distribution area of the task state and a distribution area of the rest state on the two-dimensional plane, respectively, and the mental stress determination means is based on an overlapping ratio of the distribution area of the task state and the distribution area of the rest state, Mental stress can be determined. The sympathetic parasympathetic activity calculating means calculates a normalized variance and an average heart rate from the beat interval data, and calculates the normalized variance and the average heart rate respectively as a distribution area of the task state on a two-dimensional plane. And a determination area as a distribution area of the rest state, and the mental stress determination means can also determine a change in the mental stress from a temporal change in the distance between the centers of gravity of the distribution area areas representing the task state and the rest state in the previous measurement and the current measurement. . Further, the above-mentioned sympathetic / parasympathetic nerve activity calculating means can also calculate the parasympathetic nerve activity by performing frequency analysis on the beat interval data detected by the beat interval detecting means.

[0010]

According to the mental stress determination device of the present invention, while applying a temporary stress to the subject by the task presenting means, the subject's heart rate equivalent data is collected by the heart rate equivalent data collecting means and input to the pulsation interval detecting means. The pulsation interval detection means detects the pulsation interval, inputs the pulsation interval data to the sympathetic parasympathetic activity calculating means, and based on the sympathetic parasympathetic activity calculated by the sympathetic parasympathetic activity calculating means, The presence or absence of mental stress is determined by the stress determination means. Thereby, the sensory mental stress is objectively determined.

When the mental stress determining means determines the change in the subject's response accompanying the task based on the sympathetic and parasympathetic nervous activity of the same subject measured at a plurality of different times, The status of changes in stress at the time can be easily understood. Further, when the task presenting means presents a time by the timer so that the task and the rest for a fixed time are alternately performed to the subject, a simple task is given to the subject, and the heartbeat-equivalent data is provided. Easily collected.

Further, when the task is set as an input operation to the computer, and the subject performs the input while controlling the execution speed by the computer so that the burden amount of the added task falls within a predetermined range, the body movement of the subject is small. Therefore, the heart rate equivalent data can be easily collected by a simple method, and the mental stress state can be accurately identified without being affected by individual differences. In particular, multiple targets are sequentially displayed on the display at a predetermined presentation speed,
By changing the presentation speed of the target according to the error amount of the operation of deleting and clicking the target, it is possible to easily control the burden of the task added to the subject.

Further, the above-mentioned sympathetic / parasympathetic activity calculating means obtains the distribution area of the normalized variance and the average heart rate, so that the mental stress judging means is healthy when there is no overlap and the distribution area overlaps. At some point, it can be determined that there is mental stress. In addition, by determining the temporal change of the distance between the centers of gravity of the distribution area areas representing the task state and the rest state in the previous measurement and the current measurement, it is possible to know the state of change in mental stress. Further, the above-mentioned sympathetic / parasympathetic nerve activity calculating means calculates the parasympathetic nerve activity by frequency-analyzing the pulsation interval data detected by the pulsation interval detecting means, whereby mental stress is objectively determined. You.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of a mental stress judging apparatus according to the present invention. FIG. 1 is a block diagram showing the configuration of the first embodiment, FIG. 2 is a diagram showing its use state, FIG. 3 is a diagram showing the timing at which tasks are given, FIG. 4 is a diagram explaining the principle of measurement, and FIG. It is a figure explaining the judgment point of mental stress. The mental stress determination apparatus 100 includes a task / task as a task presenting means for temporarily applying stress to a subject.
A rest presenter 101; and a heart beat equivalent data collector 102 as heart beat equivalent data collecting means for collecting heart beat equivalent data from the subject.
Is the RRI (R-R inter
val) Wired or wirelessly connected to the RRI detection circuit 103 for detecting data. The RRI detection circuit 10
Numeral 3 is connected to a sympathetic parasympathetic activity calculating circuit 104 for calculating the sympathetic parasympathetic activity, and the sympathetic parasympathetic activity calculating circuit 104 is connected to a mental stress determining circuit 105 for determining mental stress. here,
The RRI detection circuit 103, the sympathetic parasympathetic activity calculation circuit 104, and the mental stress determination circuit 105 are configured by a computer.

Then, while applying a temporary stress to the subject by the task / rest presenter 101, the pulse signal of the subject is measured by the heartbeat-equivalent data collector 102 as shown in FIG. Input to 103.
The RRI detection circuit 103 to which the pulsation signal has been input is provided with a band-pass filter. As shown in FIG. Output. Sympathetic parasympathetic activity calculating circuit 104 to which the RRI data is input
Calculates the degree of variation in RRI data, and obtains data in a task state and a rest state on a two-dimensional plane as shown in FIG. The mental stress determination circuit 105 determines the presence or absence of mental stress, which is a steady stress, from the position of each distribution area in the task state or the rest state on the two-dimensional plane.

Next, the operation of the mental stress determination device 100 will be described with reference to the flowcharts shown in FIGS. First, in step 110, a timer incorporated in the task / rest presenter 101 presents the subject with the timing of repeating the task (task) and the rest (rest) for a certain period of time. Specifically, as shown in FIG.
The task is set for about 1 minute, the rest is set for about 2 minutes,
The task and the rest are alternately and repeatedly presented multiple times. As shown in FIG. 8, the task employs an operation of writing as many circles 108 as possible within the above-mentioned predetermined time on the predetermined paper 106 whose entry position 107B is specified by the ruled line 107A.

Returning to FIG. 6, in step 111, the heartbeat of the subject is measured by the heartbeat-equivalent data collector 102, and a pulsation signal is collected as heartbeat-equivalent data. This beat signal is sampled at 100 Hz or more by the RRI detection circuit 103 and sequentially taken in. In the case of an electrocardiogram signal, an electrode needs to be attached to the body. However, in this case, since a task in which the subject does not move much is assumed, no problem occurs in measuring the heart rate. In addition, since accurate waveform diagnosis for medical use is not the purpose, it is possible to apply an electrode that is easily mounted, for example, a bee-shaped one as shown in FIG. Furthermore, the same effect can be obtained with an optically measured pulse wave signal and a pulse wave signal obtained by pressure measurement, which can be easily measured, as long as the pulse timing can be detected by appropriate signal processing.

Next, in step 112, the undesired signal is removed by the band pass filter in the RRI detection circuit 103, and the heartbeat equivalent signal is subjected to filing processing.
At step 113, the heartbeat-equivalent signal is subjected to threshold processing or the like, and at step 114, the RRI,
Find the data. However, originally, since the RRI is accompanied by fluctuations, the RRI data must be irregularly sampled in time series. Sampling is also possible.

Next, a sympathetic / parasympathetic nerve activity calculating circuit 1
In step 04, the processing of steps 115 to 121 is executed. The sympathetic parasympathetic activity calculating circuit 104
This is a circuit for calculating the degree of variation in RRI data as a time interval between beats. First, in step 115, data of about 15 seconds (16 samples in this embodiment) is analyzed from sequentially input RRI data. Cut out as a section. Next, at step 116, a normalized variance RRV and an average heart rate BEAT are calculated, and these are stored as time data of the median of the analysis section. Here, it has been experimentally confirmed that the degree of variation in the RRI data has a close correlation with the sympathetic parasympathetic nervous activity. In this embodiment,
The variance is used as an index representing the variation of the RRI data.

Next, in step 117, it is determined whether the time data of the median of the analysis section is data in the task state or data in the rest state. In the case of the task state, in step 118, the data is accumulated as task state data, and the normalized variance RRV and the average heart rate BEA according to the task state are stored.
The relationship with T is obtained as an area on a two-dimensional plane, and the center of gravity and the standard deviation are calculated. Next, step 1
Proceeding to 20, it is checked whether the presentation of the task and the rest has been completed. If the presentation of the task and the rest has not been completed, the process proceeds to step 121, and the processing of steps 115 to 117 is repeated after shifting the analysis section by one point width. Here, the reason why the analysis section is shifted by one point width is that, when analyzing the RRI data in a time-series manner, it is possible to analyze the RRI data each time it is input in the most detailed manner.

On the other hand, in the case of the rest state in step 117, the process proceeds to step 119, where the data is accumulated as the rest state data, and the relationship between the normalized variance RRV according to the rest state and the average heart rate BEAT is represented on a two-dimensional plane. In addition to calculating the area, the center of gravity and the standard deviation are calculated. Next, the process proceeds to step 120, where it is checked whether the presentation of the task and the rest is completed. If the presentation of the task and the rest has not been completed, the process proceeds to step 121 again, shifts the analysis section by one point, and repeats the processing of steps 115 to 117. The processing of steps 115 to 121 is repeated while the task and the rest are presented to the subject. Next, when the completion of the presentation of the task and the rest is checked in step 120, the process proceeds to step 122, where the mental stress determination circuit 105 compares the distribution areas on the normalized variance RRV-average heart rate BEAT two-dimensional plane. Determine mental stress.

FIG. 9 shows the normalized variance RRV and the average heart rate BE.
FIG. 11 is a diagram showing a relationship with AT, where the horizontal axis represents a normalized variance R;
RV and the average heart rate BEAT are displayed on the vertical axis.
Then, the normalized variance RRV indicates that the burden increases as the average heart rate BEAT increases as going to the left. Basically, a healthy person has a clear difference in response between when stress is applied and when it is not. That is, under non-mental stress, the distribution areas of the task state and the rest state are distributed at positions separated from each other. If the task is executed accurately, the distribution area of the task state is located at the upper left where the burden is higher than the distribution area of the rest state. This is a normal response given the sympathetic parasympathetic activity. On the other hand, in a state under mental stress, which is a background stress, a phenomenon of non-concentration in the task state and non-relaxation in the rest state occurs, and the mutual distribution areas approach each other.

FIGS. 10 and 11 show the measurement results of subjects A and B, respectively. FIGS. 10 (a) and 11 (a) show the results of FIG. b) and (b) of FIG. 11 show the results measured under a mental stress condition. In each of the figures, under the non-mental stress state, the distribution areas of the task state and the rest state are located at separate positions, and under the mental stress state, the respective distribution areas are in an overlapping state.

FIG. 12 is a flowchart showing details of the determination algorithm in step 122 of FIG. 7, and FIG. 13 is a diagram for explaining a determination example. Here, based on the area of the distribution area of the task state, the above-mentioned phenomenon is grasped by the overlapping ratio. Step 11 above
8. Gt (Rt, Bt) and St (Rt, Bt) are calculated using the center of gravity and the standard deviation obtained in step 119, respectively.
And

First, at step 130, the relative position of the center of gravity of the distribution area of the task state and the rest state on the two-dimensional plane is determined. That is, in the RRV axis direction, whether the center of gravity position Rt in the task state is on the left side of the center of gravity position Rr in the rest state in the figure, and in the BEAT axis direction, the center of gravity position Bt in the task state
Is checked in the drawing above the center of gravity position Br in the rest state, and the center of gravity positional relationship is determined. Then, the center of gravity position Rt is located to the left of the center of gravity position Rr (R
If t <Rr) and the center of gravity position Bt is above the center of gravity position Br (Bt> Br), the routine proceeds to step 131.
On the other hand, when the relationship between the center of gravity positions of the task state and the rest state does not satisfy Rt <Rr and Bt> Br, the process proceeds to step 132. In this case, it is necessary to measure again because the possibility of task default is high.

In step 131, the areas At and Ar of the distribution areas of the task state and the rest state are calculated, respectively. Thereafter, in step 133, the presence / absence of mental stress is determined based on the overlap ratio of the area area (At & Ar) where the distribution area At of the task state overlaps the distribution area area Ar of the rest state with respect to the distribution area area At in the task state. .

If the distribution area of the task state and the distribution area of the rest state do not overlap ((At & Ar) = 0) as shown in FIG.
Thus, the judgment of "no mental stress" is made. Further, as shown in FIG. 13B, the overlapping ratio of the distribution area of the rest state to the distribution area of the task state is 1 /.
If it is less than or equal to 2 ((At & Ar) ≦ At / 2), a determination is made in step 135 as “possible mental stress”. Further, as shown in FIG. 13C, when the above-mentioned overlapping ratio is 以上 or more ((At &Ar)> At)
/ 2), Step 136, "There is mental stress"
Is determined. The above steps 111 to 114 correspond to the beat interval detecting means of the present invention, steps 115 to 121 correspond to the sympathetic / parasympathetic activity calculating means, and steps 130 to 13 correspond to the present invention.
6 constitutes a mental stress determination means.

As described above, according to the first embodiment, the distribution area area At in the task state is
By determining the overlap ratio of the area area (At & Ar) where the distribution area At of the task state overlaps the distribution area Ar of the rest state, it is possible to objectively determine the presence or absence of subjective mental stress. In the first embodiment, in order to obtain a more accurate result in determining mental stress, the average heart rate BE
Although the AT information has been used to focus on the difference in the distribution area on the two-dimensional plane from the normalized variance RRV, the calculation of only the variance of the RRI data, which is the time interval of the pulsation, is slightly less accurate but simple. The same effect can be obtained. Further, if the distribution area is further displayed on the display, the overlapping state of the areas can be visually recognized, and the judgment can be easily understood intuitively.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, the state of change in mental stress is determined by comparing with the previous measurement data. First, steps 110 to 1 shown in FIGS.
According to 21, the RRV-BEAT two-dimensional area is obtained, and the center of gravity is calculated. This is stored as the previous data in step 138 of FIG. The previous task center of gravity is Gt1 (Rt1, Bt1), and the rest center of gravity is Gr1.
(Rr1, Br1). Next, in the same manner, in step 139, the task center of gravity Gt2 (Rt2, Bt2) and the rest center of gravity Gr2 (Rr2, Br2) are obtained as the data of the current two-dimensional distribution area.

At step 140, the relative position of the center of gravity of the distribution area of the task state and the rest state on the two-dimensional plane is determined. That is, in the RRV axis direction, whether or not the center of gravity Rt2 in the task state is to the left of the center of gravity Rr2 in the rest state, and in the BEAT axis direction, the center of gravity Bt2 in the task state is higher than the center of gravity Br2 in the rest state. Is checked to determine the center-of-gravity positional relationship. Then, the center of gravity position Rt2 is to the left of the center of gravity position Rr2 (Rt2 <Rr
2) If the center of gravity Bt2 is above the center of gravity Br2 (Bt2> Br2), the process proceeds to step 141. On the other hand, if the relationship between the center of gravity positions of the task state and the rest state does not satisfy Rt2 <Rr2 and Bt2> Br2, the process proceeds to step 142. In this case, measurement is performed again because the possibility of task default is high.

Next, in step 141, the distance between the centers of gravity (Gt1-Gr1) in the distribution area of the task state and the rest state measured last time, and the distance between the centers of gravity (Gt2-Gr2) in the distribution area of the task state and the rest state measured this time are calculated. ) Is calculated. Next, step 143
Then, by comparing the previous distance between the centers of gravity (Gt1−Gr1) with the current distance between the centers of gravity (Gt2−Gr2), a change in mental stress is determined.

Then, the distance between the centers of gravity (Gt2
-Gr2) is the distance between the centers of gravity (Gt1-Gr) measured last time.
(Gt1−Gr1) = (Gt2)
-Gr2)), at step 144, a determination is made of "mental stress, no change from previous time". When the distance between the centers of gravity (Gt2−Gr2) measured this time is larger than the distance between the centers of gravity (Gt1−Gr1) measured last time ((Gt1−Gr1) <(Gt2−Gr2)), in step 145, “ Mental stress is on a downtrend from the previous survey "
Is determined. Further, the distance between the centers of gravity (Gt2−Gr2) measured this time is the distance between the centers of gravity (Gt1
-Gr1) ((Gt1-Gr1)
1)> (Gt2−Gr2)), at step 146, a determination is made as to “mental stress, increasing tendency from the previous time”. Steps 140 to 146 described above constitute a mental stress determination unit. Others are the same as the first embodiment.

According to the second embodiment, when the mental stress is determined, the determination is made based on the temporal change of the distance between the centers of gravity of the respective distribution areas of the task state and the rest state with the previous determination data. Therefore, in addition to the effects of the first embodiment, it is possible to further know the state of change in mental stress. Although the first and second embodiments are described separately here, when the determination is repeated a plurality of times, the determination algorithm of the first embodiment is used for the first time, and the second algorithm is used for the second and subsequent times. It is desirable to form a processing flow of the determination operation so as to follow the algorithm of the embodiment.

Next, a third embodiment will be described with reference to FIGS.
6 will be described. The third embodiment is an example in which frequency analysis is used as a method of calculating the degree of variation in RRI data in the sympathetic / parasympathetic nerve activity calculation circuit, and the other configuration is the same as that of the first embodiment. FIG. 15A shows a state in which RRI is regularly sampled, and FIG. 15B is a diagram for explaining frequency analysis.

First, the RRI as the time interval of the pulsation shown in FIG. 4 is interpolated and regularly sampled, and as shown in FIG. A power curve of each sampled data is illustrated in FIG. Then, the power is separated into a high frequency component and a low frequency component at a predetermined frequency F0, which is 0.15 Hz in this embodiment. That is, the density function of the power spectrum obtained by performing the FFT processing on the power curve is S (f), the low frequency component is S (f) from 0 to F0, and the high frequency component is F (F).
It can be obtained by integrating from 0 to infinity, and its high frequency component reflects the activity of the parasympathetic nerve. An increase in power in a high frequency component indicates a relaxed state of the parasympathetic nerve, and a decrease in the power indicates a tension state of the parasympathetic nerve. The rise of the power in the low frequency component indicates the process of changing the parasympathetic nerve, and the fall indicates the steady process of the parasympathetic nerve.

FIG. 16 is a diagram showing the result of the frequency analysis, and shows the power of the frequency component with respect to the experiment execution time (SEC). As shown in the figure, the change amount of the high-frequency component 202 of the healthy subject is large and the change amount of the high-frequency component 203 of the subject in the mental stress state is small compared to the task execution portion 201, that is, the portion indicating the concentration state. . Therefore, it is possible to determine the mental stress based on the difference in the change amount of the high frequency component.

As described above, according to the third embodiment, regular sampling is performed by interpolating the RRI as the time interval of the subject's pulsation, and the low frequency component and the high frequency component are separated at a predetermined frequency. Separate and perform frequency analysis. Since the high frequency component reflects the activity of the parasympathetic nerve, the state of mental stress can be objectively determined.

According to the present invention, steady stress is determined by temporarily adding a task as described above. However, as shown in FIG. The phenomenon of non-relaxation in a concentrated or rest state occurs, and the mutual distribution areas come closer. Such "cases where the user cannot concentrate on the task at the time of the task" and "cases at which the user cannot relax at the time of the rest" need to be careful, assuming that the subject is performing the task with a predetermined burden. However, there is an individual difference in the temporary task load for the same task, and when the subject performs the task leisurely, the subject appears in the distribution area as a “case not concentrated on the task”. The “case not concentrated” and the “case not concentrated” have basically the same influence on the autonomic nervous system, and therefore have the same distribution on the two-dimensional plane of the RRV-BEAT. It may be difficult to attach.

Therefore, in each of the above-described embodiments, the task of writing a circle on a predetermined sheet has been exemplified as a task.
As shown in FIG. 7, when a circle 303 is entered in the same entry column 302 as in the first embodiment, a pen 301 which can be input to the computer 300 using a pen 301 and a pen 304 is used. Tasks can be executed while controlling the error rate. In this case, task and rest time and achievement level management become easy, and the task can be given more effectively. The task and rest times were about 1 minute and 2 minutes, respectively.
It is preferable that the setting can be variably set according to the age of the subject. A method is also possible in which a computer forcibly performs work such as mental arithmetic while controlling the execution speed and the error rate with a computer. The task is applicable as long as the content can give a subject mental stress. At this time, the subject is forcibly performed within a range that does not give up.

Next, a fourth embodiment of the present invention will be described with reference to a fourth embodiment in which the temporary task load is adaptively controlled in accordance with the individual difference so that the load of the added task falls within a predetermined range. It will be described as. FIG. 18 is a diagram showing the configuration of the fourth embodiment. In this mental stress determination device, the RRI detection circuit 103 detects the time interval of the beat based on the data obtained by the heartbeat-equivalent data collection device 102 while giving the task to the subject by the task presentation control device 401. ing. Further, the RRI detection circuit 1
03 and the sympathetic parasympathetic activity calculating circuit 104,
A defect data removal circuit 404 is provided. Then, similarly to the first embodiment, the sympathetic parasympathetic nerve activity calculating circuit 1
04 is connected to the mental stress determination circuit 105.

The task presentation control device 401 comprises a presentation speed control circuit 402 and a target presentation device 403.
As shown in FIG. 19, the target presentation device 403 includes a desktop computer display 410 placed in front of the subject, and displays a circle 412 as a target on the display 410. The presentation speed control circuit 402 uses a built-in timer to set the timing for repeating the task and rest for a certain period of time,
The target presentation device 403 is controlled so that the circles 412 are displayed one after another, while being erased after a predetermined time. The task of clicking on the displayed circle 412 by mouse operation before the displayed circle 412 is deleted is imposed on the subject as a task.

The presentation speed control circuit 402 uses the circle 412
Are stored in a plurality of types of memories, and connected to the heartbeat-equivalent data collector 102, and the presentation (display) time of the circle 412 is selected while referring to the current heart rate. Specifically, as shown in FIG. 20, the target heart rate is defined as a target heart rate that is a few percent increase in the subject's normal heart rate, and is compared with the changing current heart rate of the subject during the task. The presentation speed of appearance elimination is selected. In principle, if the current heart rate is lower than the target heart rate, the presentation speed is increased to increase the task difficulty, and if the current heart rate is higher than the target heart rate, the presentation speed is reduced to decrease the task difficulty.

On the other hand, the RRI detection circuit 103 detects the RRI data from the heartbeat-equivalent data and outputs it to the sympathetic / parasympathetic nervous activity calculation circuit 104. During that time, if the heartbeat-equivalent data contains defect data due to arrhythmia or the like, , And the RRI data based thereon are skipped by the defect data removal circuit 404.

FIGS. 21 and 22 show the task presentation control device 40.
3 is a flowchart showing a flow of a task presentation process in FIG. First, in step 601, reference measurement is performed before the start of the repetition of the task and the rest.
Here, the heart rate is measured at normal times by measuring for 2 minutes after the subject is kept in a sitting state on a chair, and the average value is set as a reference heart rate Nk (times / minute).
Then, in step 602, the target heart rate is set at 5 of the reference heart rate.
%, That is, set as Nt = 1.05 * Nk.

Next, in step 603, the task start timing is checked based on the count of the internal timer, and the start of the task is displayed together with the character display on the display and the beep sound of the computer. An initial value for speed is selected. The presentation speed is represented by a time interval from the presentation of one target to the presentation of the next target. Here, 450, 5 per target (circle)
00, 625, 750, 875, 1000 msec 6
The kind of presentation speed is prepared in the memory, and the initial value is set to 750 msec, which is reasonable for performing the task.

In step 605, circles (targets) are sequentially presented one by one at this time interval on the display, and are sequentially erased in synchronization with the presentation speed. For example, about 5)
Is controlled to be displayed. This task is continued for 10 seconds. Targets that cannot be clicked with the mouse and have been deleted are counted as errors Pe.
Are sequentially stored. During this time, the current heart rate is also continuously measured.

Thereafter, in step 606, it is checked whether or not the task time (for example, one minute) set as the repetition timing of the task and the rest has ended. If not completed, in the next step 607, the number Pe of errors after 10 seconds has elapsed is checked. If the number of errors is three or more, it is highly likely that the subject has given up.
In step 605, the presentation speed is reduced by one step, for example, to 875 msec, regardless of the current heart rate.
Return to

If the number of errors is less than 3 in the check in step 607, the flow advances to step 609 for 10 seconds.
The average current heart rate Np (times / minute) during this is determined. In the next step 610, the current heart rate Np is changed to the target heart rate N
It is compared with a predetermined width including t. The current heart rate Np is (Nt
If it is lower than -1), the presentation speed is increased by one step in step 611 to increase the task difficulty, and if the current heart rate Np is higher than (Nt + 1), the presentation speed is decreased by one step in step 612. Reduce task difficulty. And
When the current heart rate Np is between (Nt-1) and (Nt + 1), the same presentation speed is maintained. Thereafter, the process returns to step 605. Thus, 10 seconds during task execution
Each time, an error check and a predetermined presentation speed update are performed.

If it is determined in step 606 that the task time has ended, step 613 is executed.
Then, it is checked whether or not a series of preset tasks and the repetitive presentation of the rest are completed. If it has not ended, the process returns to step 603, the next task is started after the predetermined rest, and the above flow is repeated. If the repetitive presentation of a series of tasks and rests has been completed, the process ends.

Next, FIG. 23 shows a flow of operation from the acquisition of data corresponding to the heartbeat to the calculation of the sympathetic and parasympathetic nervous activity. Here, steps 701 and 702 are added between steps 114 and 115 of the flow in the first embodiment of FIGS. After the RRI data is detected in step 114, in step 701, the defect data removal circuit 404 checks whether or not the time interval between beats is within a predetermined range. Here, when the new data RRI (1) is detected, the data R
Referring to RI (0), (1/2) RRI (0) to (3)
/ 2) Set the range of RRI (0) as the detection range.
If the pulsation is lacking due to arrhythmia, the RRI will be about twice as large as usual, and can be detected by this check. That is, RRI (1)
Is within the above range, it is sent to the sympathetic / parasympathetic activity calculating circuit 104 as it is, and proceeds to the next step 115. After the time information is updated in step 702,
Proceed to 15.

The settings from (1/2) to (3/2)
Mental tasks rely on no more than 50% instantaneous change. The arrhythmia in a subject living a normal life returns to the normal pulsation even if the phenomenon occurs, and the subsequent pulsation can be used again for determination.

In step 115, the sympathetic parasympathetic activity calculating circuit 104 calculates the degree of variation in the RRI data. Others are the same as the flow of FIG. 6 and FIG.

According to this, the defect data removing circuit 404 is provided between the RRI detecting circuit 103 and the sympathetic / parasympathetic nervous activity calculating circuit 104 so that the time interval of the pulsation is within a predetermined range with respect to the immediately preceding data. Since only data that is present is used as data, highly accurate determination is performed even when pulsation is lacking due to arrhythmia. Here, the task presentation control device 401 constitutes a task presentation unit that applies a temporary stress to the subject.

The present embodiment is configured as described above, and is provided with a task presentation control device having a presentation speed control circuit. The task difficulty is changed according to the target presentation speed, so that a task with a constant amount of burden is always given to the subject. Since the addition is performed, it is prevented that it is difficult to distinguish between the “unconcentrated case” and the “unconcentrated case” during the task, and the determination accuracy is further improved. In addition, since the defect data removal circuit uses only data whose pulsation time interval is within a predetermined range with respect to the immediately preceding data as data, even if pulsation may be missing due to arrhythmia, High accuracy judgment is maintained.

In the embodiment, an example in which the target is presented on the display 410 of the desktop is shown. However, the task presentation control device is incorporated in the portable terminal, and the pulse wave detectable from the fingertip or the like is used as the heartbeat equivalent data. In addition, since the entire apparatus is configured to be small and lightweight, there is an advantage that heartbeat-equivalent data can be collected easily and frequently, and detailed determination and analysis can be easily performed.

[0056]

As described above, according to the mental stress judging device according to the present invention, while applying a temporary stress to the subject, the heartbeat equivalent data of the subject is collected to detect the pulsation interval, and the pulsation is detected. When calculating the activity of the sympathetic parasympathetic nerve based on the interval data, the sympathetic parasympathetic nerve activity was calculated in a state where temporary stress was applied, and the mental stress was determined by focusing on the change, It is possible to perform highly accurate objective judgment based on a physiological background with respect to stationary mental stress that can be evaluated only by conventional subjective evaluation.

When the above mental stress is determined based on the change in the subject's response accompanying the task execution based on the sympathetic and parasympathetic nervous activity of the same subject measured at a plurality of different times, the change in the mental stress is determined. The situation can be easily known, and the determination accuracy can be improved. In addition, when giving a task to a subject, a timer can provide a simple task to the subject by presenting the time so that the task and the rest for a fixed time are alternately performed. Equivalent data can be easily collected.

Also, the task is an input operation to the computer, and the subject is made to input while controlling the execution speed by the computer so that the burden of the added task falls within a predetermined range. It can be easily collected by a simple method and can accurately identify the mental stress state without being affected by individual differences. At this time, a plurality of targets are sequentially displayed and erased on the display at a predetermined presentation speed, and the target presentation speed is changed according to the error amount of the operation of clicking the target, thereby burdening the subject with the task. The quantity can be easily controlled.

Further, a normalized variance and an average heart rate are calculated from the beat interval data, and a two-dimensional distribution area of the normalized variance and the average heart rate is obtained. When the distribution areas overlap, mental stress is reduced. Yes, when there is no overlap of the areas, it can be determined that there is no mental stress, so that an objective determination can be made. In addition, by determining the temporal change of the distance between the centers of gravity of the distribution areas of the task state and the rest state in the previous measurement and the current measurement, it is possible to know the state of change in mental stress, and to improve determination accuracy. it can. The mental stress can also be objectively determined by calculating the parasympathetic nervous activity by frequency analysis of the beat interval data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a use state of the first embodiment.

FIG. 3 is a diagram showing a task presentation timing in the first embodiment.

FIG. 4 is a diagram for explaining a principle of measuring a heartbeat in the first embodiment.

FIG. 5 is a diagram illustrating a procedure for determining mental stress in the first embodiment.

FIG. 6 is a flowchart illustrating a flow of an operation of mental stress determination in the first embodiment.

FIG. 7 is a flowchart showing a flow of an operation of mental stress determination in the first embodiment.

FIG. 8 is a diagram illustrating tasks in the first embodiment.

FIG. 9 is a diagram for explaining the principle of determining mental stress in the first embodiment.

FIG. 10 is a diagram illustrating a determination example in the first embodiment.

FIG. 11 is a diagram illustrating a determination example according to the first embodiment.

FIG. 12 is a diagram for explaining the operation of the mental stress determination circuit in the first embodiment.

FIG. 13 is a diagram illustrating a determination example of a mental stress determination circuit in the first embodiment.

FIG. 14 is a diagram illustrating the operation of the mental stress determination circuit according to the second embodiment.

FIG. 15 is a diagram for explaining the principle of determining mental stress in the third embodiment.

FIG. 16 is a diagram illustrating a procedure for determining mental stress in the third embodiment.

FIG. 17 is a diagram illustrating another example of a task.

FIG. 18 is a block diagram showing a configuration of a fourth embodiment.

FIG. 19 is a diagram illustrating a task presentation example in the fourth embodiment.

FIG. 20 is a diagram showing a control procedure of a task presentation speed.

FIG. 21 is a flowchart showing the flow of a task presentation process.

FIG. 22 is a flowchart illustrating a flow of a task presentation process.

FIG. 23 is a flowchart showing a flow of an operation for determining mental stress in the fourth embodiment.

FIG. 24 is a block diagram showing a configuration of a conventional stress level measuring device.

FIG. 25 is a diagram illustrating a measurement principle of a conventional stress level measurement device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Mental stress determination device 101 Task / rest presenter 102 Heart rate equivalent data collector 103 RRI detection circuit 104 Sympathetic parasympathetic activity calculation circuit 105 Mental stress determination circuit 300 Computer 301 Board 302 Entry column 303 Circle 304 Pen 401 Task presentation control Device 402 Presentation speed control circuit 403 Target presentation device 404 Defect data removal circuit 410 Display 412 Circle

Claims (8)

[Claims] 1. A task presenting means for temporarily applying stress to a subject, a heart rate equivalent data collecting means for collecting heart rate equivalent data of the subject, and a pulsation based on the heart rate equivalent data collected by the heart rate equivalent data collecting means. Pulsating interval detecting means for detecting an interval; sympathetic / parasympathetic nervous activity calculating means for calculating a sympathetic / parasympathetic nervous activity based on pulsating interval data detected by the pulsating interval detecting means; A mental stress determination device comprising: a mental stress determination unit that determines mental stress based on the sympathetic parasympathetic nerve activity calculated by the degree calculation unit. 2. The mental stress judging means observes a change in a subject's response accompanying the task based on the sympathetic and parasympathetic nervous activity of the same subject based on heartbeat-equivalent data collected at a plurality of different times. By doing
The mental stress is determined.
The mental stress determination device described in the above. 3. The task presenting means includes a timer,
The mental stress determination device according to claim 1 or 2, wherein a time is presented by a timer so that the subject alternately performs a task and a rest for a predetermined time. 4. The task presenting means includes a computer, and the task is an input operation to the computer.
4. The mental stress determination according to claim 1, wherein the subject is made to perform an input while controlling an execution speed by the computer so that a burden amount of the added task falls within a predetermined range. apparatus. 5. The task presenting means sequentially displays a plurality of targets on a display at a predetermined presentation speed and erases each of them after a predetermined time, and the input operation is performed while the targets are being displayed. 5. The mental stress according to claim 4, wherein the cursor is clicked by superimposing the cursor on the target, and the task presentation means changes the presentation speed of the target in accordance with an operation error amount at a predetermined set time. Judgment device. 6. The sympathetic / parasympathetic nervous activity calculating means,
A normalized variance and an average heart rate are calculated from the beat interval data detected by the beat interval detecting means, and the normalized variance and the average heart rate are respectively calculated on the two-dimensional plane. The method according to claim 1, wherein the mental stress is determined as a distribution area, and the mental stress determination unit determines a mental stress based on an overlapping rate of areas of the distribution area of the task state and the distribution area of the rest state. The mental stress determination device according to 3, 4, or 5. 7. The sympathetic / parasympathetic nerve activity calculating means,
A normalized variance and an average heart rate are calculated from the beat interval data detected by the beat interval detecting means, and the normalized variance and the average heart rate are respectively calculated on the two-dimensional plane. Determined as a distribution area, the mental stress determination means, from the temporal change of the distance between the centroid of the distribution area area representing the task state and the centroid of the distribution area area representing the rest state in the previous measurement and the current measurement, the mental stress of the mental stress The mental stress determination device according to claim 1, wherein the change is determined. 8. The sympathetic parasympathetic nerve activity calculating means,
6. The mental stress determination device according to claim 1, wherein the parasympathetic nervous activity is calculated by frequency-analyzing the beat interval data detected by the beat interval detecting means. .