JP5302911B2 - Fatigue level evaluation system, in-house fatigue level evaluation system and fatigue level evaluation method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an objective and quantitative fatigue evaluation system and method being simply implemented in daily life. <P>SOLUTION: The fatigue evaluation system makes a subject to memorize the positions of figures or language sound using a program operating on a computing machine represented by a PC, presents stimulations for testing the memory after a prescribed time, and acquires a reaction time to the stimulations. While the subject remembers them, the fatigue evaluation system sets two conditions, a condition for performing an attention task (non-coincidence condition) causing cognitive conflict and a condition for performing an attention task (a coincidence condition) causing no cognitive conflict, calculates a fatigue index using the reaction time to both the memory tasks, and displays the fatigue index and/or an evaluation result derived from the fatigue index. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fatigue level evaluation system, an in-house fatigue level evaluation system and a fatigue level evaluation method using the same, and in particular, a fatigue level evaluation system suitable for calculating and evaluating the mental fatigue level of a subject, and It relates to the evaluation method.

There are cases where equipment is misoperated or develops into mental health problems due to mental and physical fatigue in the workplace. Since early detection of fatigue states leads to prevention of various problems, development of an effective fatigue evaluation method is required. General fatigue evaluation methods can be roughly classified into the following three types.
(1) Method of evaluating subjective fatigue using questionnaires, etc. (2) Method of evaluating fatigue level based on physiological responses such as heart rate changes (3) Evaluation of fatigue level based on objectively observable workload and behavior data Method Regarding (1) above, answer whether or not you are applicable to multiple items such as “I feel dull”, “I feel dull”, “I feel distracted”, and evaluate the degree of fatigue from the total score. Represented by "Study on subjective symptoms (Industrial Fatigue Study Group, Japan Society for Occupational Health)". There is also a method for answering the subjective “fatigue level” on a discrete or continuous scale. These methods have the advantage that the feeling of fatigue felt by the subject is directly reflected.

  Regarding (2) above, a method is known in which myoelectricity, heart rate, respiration, oxygen consumption, etc. are measured to evaluate the degree of fatigue. These methods are considered to be suitable for evaluating physical fatigue such as muscle fatigue.

  For the above (3), for example, the flicker method is known. This is to measure the frequency of the boundary where the blinking light is seen from continuous light to continuous light, and is considered to be effective for visual fatigue evaluation. In addition, there is a method for evaluating the degree of fatigue by using work amount monitoring and behavior index measurement. For example, Patent Document 1 discloses an apparatus that measures a subject's reaction time relationship with a presented figure and evaluates the degree of fatigue. Specifically, under the condition that the subject was instructed to press the key as soon as possible for the figure displayed on the display at irregular intervals, the time from when the figure was displayed until the subject pressed the key was measured. The fatigue level is evaluated according to the time. Similarly, Patent Document 2 discloses a method of measuring the degree of fatigue related to driving operation using a reaction time for a moving image. These methods make use of the phenomenon that the amount of work per unit time decreases when the subject is tired or the response time to the stimulus to be reacted increases, and the fatigue level is visualized quantitatively. effective.

JP 7-111989 A JP 2004-267339 A

  The above-described conventional fatigue level evaluation method has the following problems, but the fatigue level evaluation method using the questionnaire (1) has a disadvantage that subject's bias and subjective operation are included. This indicates that the test result can be manipulated by the subject, for example, when he wants to swing tired or hides fatigue. In other words, objective bias and intentional manipulation can be included, making objective and quantitative evaluation difficult. In addition, it is difficult to detect fatigue that the subject is not aware of, and it is not suitable for preventive use to prevent human error due to potential fatigue.

  The method (2) of fatigue evaluation method using physiological reaction such as heart rate change has a problem that it is not suitable for mental fatigue evaluation of workers engaged in office work. In addition, it is necessary to wear a measuring device for measurement, and it is difficult to use as a daily fatigue monitor. Another problem is that it is not suitable for evaluation of mental fatigue and is difficult to use on a daily basis because it requires a measuring instrument.

  Further, with regard to the fatigue level evaluation method using the work amount and behavior data in (3) above, the boundary that appears to be continuous light from intermittent light is identified by the subject's report (button pressing timing). There is a possibility that an intentional operation may be performed in the same manner as the method of In the methods disclosed in Patent Documents 1 and 2, when only a simple work amount or reaction time is used as an index, there is room for subject's intentional operation as in other methods. Although there is a possibility that even unconscious fatigue can be detected, there is a problem that there is room for subjective operation as in the method (1).

  An object of the present invention is to solve the above problems and provide a technique for evaluating mental fatigue. In other words, it is a method that cannot be intentionally operated by the subject, and it is easy to measure and display objective and quantitative indicators of mental fatigue that are effective in preventing human errors and improving mental health in the workplace. It is an object of the present invention to provide a system and method that allows to do so.

A typical configuration of the present invention is as follows. The fatigue evaluation system of the present invention stores a presenting means for presenting a subject to a subject, an input means for receiving a response from the subject, a task sequence, and a fatigue index calculation formula based on the task sequence Storage means, calculation means for calculating the fatigue level, output means for outputting the fatigue level evaluation result, and control means,
The task sequence is composed of a combination of at least a memory task that requires memory and a caution task that is inserted between presentation of the memory task and requires attention;
The control means presents the task sequence to the presenting means, stores an answer and a response time as the response to the task sequence in the storage means, and based on the fatigue index calculation formula from the answer and the reaction time A fatigue index is calculated by the calculation means, and a fatigue evaluation result based on the fatigue index is output to the output means.

  According to the present invention, the subject is prevented from intentionally manipulating the value of the fatigue level by calculating an index of the mental fatigue level by using a subtle difference in reaction time for a plurality of antagonistic cognitive tasks. can do. Further, since the mental fatigue level can be easily measured on existing equipment and facilities such as a personal computer (PC) and a portable information communication terminal, it can be introduced at a low cost without requiring a special device.

The schematic diagram which shows the structure of the fatigue evaluation system used as the 1st Example of this invention. The flowchart which shows the whole process of the 1st Example of this invention. The schematic diagram which shows the subject sequence A (The spatial memory | storage task which pinched | interposed the attention subject of a matching condition) in a 1st Example. The example of the screen of the subject sequence A (memory | storage task) presentation to a test subject in a 1st Example. The example of the screen of the subject sequence A (attention subject) presentation to a test subject. The example of the screen of the subject sequence A (memory task) presentation to a test subject. The schematic diagram which shows the subject sequence B (The spatial memory | storage task which pinched | interposed the attention subject of mismatch condition) in a 1st Example. The schematic diagram which shows the task sequence C (the linguistic memory task on which the attention task of a matching condition is pinched | interposed) in a 1st Example. The example of the screen of the subject sequence C (memory task) presentation to a test subject. The schematic diagram which shows the task sequence D (the linguistic memory task on which the attention task of a mismatch condition is pinched | interposed) in a 1st Example. The graph which shows the reaction time with respect to the memory | storage subject of each condition in a 1st Example. The correlation chart of the reaction time index (disagreement condition-matching condition) with respect to the spatial memory task and the fatigue score measured with the questionnaire in the first example. The correlation graph of the reaction time parameter | index (disagreement condition-matching condition) with respect to a linguistic memory task, and the fatigue score measured with the questionnaire. The correlation figure of the difference of the reaction time parameter | index of a spatial memory task and a linguistic memory task, and the fatigue score measured with the questionnaire. The figure which shows the example of the judgment criteria of the fatigue degree in a 1st Example. The flowchart which shows the whole the subject presentation process in the fatigue evaluation system which becomes a 2nd Example of this invention. The example of the setting screen of the stimulus presentation parameter in a 2nd Example. Example of setting screen for reaction acquisition parameters. Example of feedback information setting screen. An example of a setting file in the second embodiment. The flowchart which shows the subject presentation process in a 2nd Example. The flowchart which shows the subject presentation process in the modification of a 2nd Example. The flowchart which shows the fatigue parameter | index calculation process in a 2nd Example. The example which displayed only the fatigue parameter | index as a feedback screen to a test subject in a 2nd Example. An example in which only comments are displayed as a feedback screen to the subject. An example of displaying a fatigue index and a comment as a feedback screen to the subject. The example of the screen which displayed the time series change of the fatigue degree in the fatigue evaluation system which becomes the 3rd Example of this invention. The schematic diagram which shows the structure of the fatigue evaluation system which becomes the 4th Example of this invention. The flowchart which shows the whole process of the 4th Example of this invention.

  The present invention provides a system and method for measuring an action index for a cognitive task and calculating / displaying the fatigue level of a subject. The inventor of the present application presents the subject with a combination of at least a cognitive task that requires memory and a cognitive task that requires attention as a task sequence, in other words, tests the subject's memory after a predetermined time has elapsed after the presentation. An experiment that presents a combination of a memory task and a caution task inserted between the presentation of the memory task and can quantitatively evaluate a subject's fatigue level by detecting a difference in their reaction time index It was found by. Therefore, in the present invention, the subject is presented with a cognitive task that requires memory and a cognitive task that requires attention, the subject's answer to each cognitive task and its reaction time are obtained as answer data, and the subject's fatigue is obtained using the answer data. Calculate the indicator. Note that the task requiring attention is more preferably a combination of the disagreement condition and each task of the matching condition.

  According to the present invention, since the fatigue index is calculated using a subtle difference in reaction time for a plurality of antagonized cognitive tasks, it is possible to prevent a subject's intentional operation. That is, it is possible to prevent the subject from intentionally manipulating the value of the fatigue level.

Further, according to the present invention, since it can be measured using a personal computer (hereinafter referred to as a PC) or a portable information communication terminal that is already becoming a social infrastructure, the mental fatigue state of the subject can be evaluated daily and easily. can do. That is, it is possible to record a reaction to a cognitive task and to measure and feed back the fatigue level objectively and quantitatively by software running on an existing electronic device. Since it can be easily measured on a PC, it can be introduced at a low cost without requiring a special device.
Moreover, since it can be carried out in a short time using a simple task, it is possible to easily check the fatigue level during daily office work. Moreover, since it can carry out without using the image and phrase related to "fatigue", the fatigue index in a natural mood state is obtained.
Hereinafter, embodiments of the present invention will be described.

  A fatigue evaluation system according to a first embodiment of the present invention will be described with reference to FIGS. The overall system configuration of this embodiment is shown in FIG. The fatigue evaluation system 100 includes an input unit 101 that receives input from the subject 120 or an experimenter, and a control unit 102 that controls the overall processing such as storage processing, calculation processing, presentation processing, and input / output processing executed by these, the subject Presenting means (display means) 103 for presenting and displaying tasks to 120, calculation means 104 for calculating fatigue index, etc., fatigue evaluation program, information on “cognitive tasks”, answer data from subjects and fatigue index Storage means 105 for storing information necessary for the calculation in a table format, etc., output means 106 for outputting / displaying evaluation results and comments, and communication means 107. As the input unit 101, the presenting unit 103, and the output unit 106, a common display screen (see FIGS. 4A to 4C) having a GUI function may be used. The storage unit 105 includes various memories and a hard disk, and stores information such as measurement parameters and comments. The cognitive task performed by the system of the present embodiment, that is, the “task sequence” includes at least a target task for storing a figure position and language, a memory task including a probe stimulus for testing the memory after a predetermined time, and an arrow It consists of two tasks of attention tasks that require attention to determine the orientation of the task, and uses one type of task sequence or a combination of two types of task sequences among a plurality of “task sequences” stored in the storage means 105 Diagnosis is performed. The “task sequence” of the present invention is a caution task inserted between a memory task for testing a subject's memory after a predetermined time has passed as a first cognitive task and the first cognitive task as a second cognitive task. It consists of and. In this invention, what implements another recognition task in the form inserted in one recognition task in this way is defined as a branching task.

FIG. 2 is a flowchart showing the entire processing of the first embodiment of the present invention.
First, the fatigue evaluation system 100 accepts initial settings for information necessary for measuring the fatigue (S200). The initial setting items include, for example, the types of cognitive tasks (memory task, attention task), the number of times of presentation, etc. These may be preset initial values or the like. The subject himself / herself may select and set the “cognitive task” by operating. Alternatively, an experimenter who has knowledge about the fatigue evaluation system may input initial values and the like. Here, it is assumed that a combination of assignment sequence A and assignment sequence B is set. A specific example of the task sequence will be described later in detail.

  The fatigue evaluation system 100 presents the set task sequence A to the presenting means 103, and records the response of the subject 120 and the reaction time for this (S202 to S226). In the task sequence A presentation process, the memory task (target) is presented (S202), the attention task is presented and the subject's response and the response time are recorded (S204 to S208), the memory task (probe) is presented and this The response of the test subject and the recording of the reaction time (S210 to S212) are included. Further, as the task sequence B presenting process, the memory task (target) is presented (S214), the attention task is presented and the subject's response and the response time are recorded (S216 to S220), and the memory task (probe) is presented. The test subject's answer to this and the record of the reaction time (S222 to S224) are included. Finally, the fatigue evaluation system 100 performs a process for calculating the fatigue index of the subject based on the measurement result for the task sequence (S230) and a process for displaying the evaluation result on the output means (S232).

  FIG. 3 shows a configuration example of the task sequence A. The direction of the arrow indicates the passage of time. In the memory task, after presenting the background screen 300 having the gazing point (+), the spatial memory task in which the target stimulus 301 on which the four squares are displayed is first displayed for 1500 ms and the position is stored in the subject is used. After presenting the target stimulus 301, attention tasks 302 to 304 that cause the subject to determine the direction of the arrow were presented. FIG. 4A shows an example of a display screen 400 for presenting a memory task to a subject in the first embodiment. In FIG. 4A, reference numeral 402 is a task sequence presentation screen, 404 is a message to the subject regarding the task sequence, 406 is an answer operation icon for the subject, 408 is an operation button, and 410 is a numeric keypad. FIG. 4B shows an example of a screen for presenting the attention task to the subject.

  Returning to FIG. 3, the probe stimulus 305 is displayed after 7000 ms has elapsed since the presentation of the target stimulus 301, and the square position in the probe stimulus 305 matches any of the stored square positions in the target stimulus 301. This is determined by the test subject's button press. FIG. 4C shows an example of a screen for presenting a target stimulus to a subject. The time from when the probe stimulus 305 is displayed until the button is pressed is recorded as the reaction time of the subject.

  Here, four squares are displayed as target stimuli to be stored. However, any figure may be used, and the number of figures to be remembered may be appropriately selected from 1 to 10. The necessary point is to include spatial location information that can be stored. The presentation time is not limited to 1500 ms as long as the subject can recognize information to be stored. Similarly, the time (memory retention time) from the presentation of the target stimulus to the presentation of the probe stimulus is not limited to 7000 ms.

  The above parameters (type and number of figures, presentation time, memory retention time) are adjusted by the degree of difficulty with reference to the average memory ability of the subject or the subject group. For example, it is desirable that the degree of difficulty is such that the subject can correctly answer with a certain probability or more if he / she concentrates, although he / she cannot perform it.

  In this cognitive task, an attention task for determining the direction of the arrow is inserted into the memory task. That is, a branching task is performed. After gazing point (+) is displayed for 500 ms next to target stimulus 301, attention task 302 is displayed for a maximum of 1900 ms, and as soon as the subject's reaction is input, the gazing point (+) is switched. In this example, the attention task was repeated three times every 2000 ms. The presentation time and the number of repetitions of the attention task are not limited to this example, but are adjusted with reference to the length of the memory task, the overall difficulty level, and the like. The attention task used in this example is to answer the direction of the center arrow of the five side-by-side arrows on the left or right, and is called a flanker task in the field of cognitive psychology. The attention tasks 302 to 304 of the task sequence A are referred to as congruent conditions in which five arrows are directed in the same direction. Since all the arrows point in the same direction, the subject can determine the direction without being relatively lost.

  On the other hand, FIG. 5 shows an example of a task sequence B that is substantially the same as the task sequence A of FIG. In the attention tasks 502 to 505 in the task sequence B, the center arrow and the other four points in opposite directions. This is called an incongruent condition. In this case, since the directions of the surrounding arrows are different, it is difficult to determine the direction of the center arrow, and it is known that the reaction time is delayed. Here, the flanker task that determines the direction of the arrow is used as an example of the attention task. However, the attention task that is used in the present invention is not limited to the flanker task. It is only necessary to satisfy that two conditions can be set: a mismatch condition including an element that causes (cognitive interference) and a matching condition that does not include an element that disturbs the determination (causes cognitive interference).

  In addition, the attention task includes three conditions including a neutral condition in addition to a mismatch condition designed to cause cognitive interference and a matching condition designed not to cause cognitive interference. You may comprise by conditions, or you may comprise by the conditions of the multilayer level which changed the difficulty level in each of multistep about a mismatch condition and a matching condition.

  The storage task (501, 505) of the task sequence B shown in FIG. 5 is exactly the same as the task sequence A. The difference between the task sequences A and B is the condition of the attention task (matching condition / Only mismatch condition). The present invention calculates an index representing the degree of fatigue using the difference or ratio between the reaction time for the memory task in the task sequence A (match condition) and the reaction time for the memory task in the task sequence B (mismatch condition). Features. Also, instead of a spatial memory task for storing the position of a figure, a linguistic memory task for storing linguistic information such as phonemes, or a figure shape memory task for storing shape information such as the color, shape, and character of a figure It is also useful to use it alone.

  An example of a task sequence using a linguistic memory task is shown in a task sequence C in FIG. 6A and a task sequence D in FIG. Here, as shown in the example of the presentation screen in FIG. 6B, one katakana character (in the example, “4” hiragana characters are remembered as targets (target stimuli (601, 701) and displayed as probe stimuli 605, 705). It is determined whether or not the character of the same voice as “No”) was found in the four hiragana characters learned before. Except for the type of information to be stored in the memory task, the task sequence A has the same structure as the task sequence A in FIG. 3 and the task sequence C in FIG. 5 including the attention task (602 to 604, 702 to 704). As combinations of task sequences C and D using linguistic memory tasks, uppercase letters A, B, C,-and lowercase letters A, B, C,-, numbers 1, 2, 3,-and English one, two A combination of different characters having the same voice, such as, three, and-may be used.

  The reason why the fatigue level can be evaluated by using the difference in reaction time for the branching task under different conditions is shown below.

  As described above, the spatial memory branching task (matching condition) (FIG. 3, task sequence A), the spatial memory branching task (mismatching condition) (FIG. 5, task sequence B), the linguistic memory branch 4 conditions were set, including a linguistic task (matching condition) (FIG. 6A, task sequence C) and a linguistic memory branching task (mismatching condition) (FIG. 7, task sequence D). . The square positions, character types, and correct / incorrect answers used in each task were pseudo-randomized to avoid biasing to the same images and answers. FIG. 8 shows the result of calculating the average reaction time of all subjects by experimenting 5 times for each subject.

  As shown in FIG. 8, in the spatial memory branching task, it was found that the reaction time in the mismatch condition (task sequence B) is longer than the reaction time in the matching condition (task sequence A). This is a natural result that can be interpreted as a slow response to the memory task because the attention task of the inserted mismatch condition is difficult. On the other hand, in the linguistic memory branching task, it was found that the reaction time in the matching condition (task sequence C) is longer than the reaction time in the mismatch condition (task sequence D). The phenomenon that the response to the memory task becomes faster when a mismatch condition that should be difficult as a difficulty level is inserted is a new finding that has not been known so far.

  This indicates that the disagreement condition of the attention task used in this experiment had the effect of enhancing some processing in the language memory task. Although this process cannot be specified from this experiment, a candidate is a spoken language storage process using a speech loop or a katakana (shape) recognition process displayed as a target.

  In FIG. 9A and FIG. 9B, this “difference in reaction time with respect to a memory task caused by whether the attention task is a matching condition or a mismatching condition” is used as a reaction time index (mismatching condition−matching condition). The result of having investigated the correlation with "fatigue degree" of a test subject is shown.

  Here, the fatigue score and POMS (fatigue) evaluated by the standardized questionnaire “POMS shortened version” (edited by Kazuhito Yokoyama, “POMS shortened version guide and case explanation”, Kaneko Shobo, 2005) that evaluates the mood of subjects Used as the degree of fatigue. In the spatial memory blanching, it was shown that the fatigue level becomes smaller as the reaction time in the mismatch condition becomes slower than the reaction time in the match condition. That is, the reaction time index and the degree of fatigue show a negative correlation (correlation coefficient -0.54). On the other hand, in linguistic memory branching, it was shown that the fatigue level decreases as the reaction time in the mismatch condition becomes faster than the reaction time in the match condition. That is, the reaction time index and the degree of fatigue show a positive correlation (correlation coefficient 0.53).

  How to interpret this phenomenon. In the spatial memory branching task, the reaction time in the mismatch condition (task sequence B) tends to be slower than the reaction time in the matching condition (task sequence A), and the fatigue level is higher as this tendency is weakened. This can be considered that when the user is not tired, attention can be paid strongly to the mismatch condition, and as a result, the response to the next target stimulus is delayed. In other words, it may indicate whether or not there is a sharp attention control according to the difference between the agreement and disagreement of the attention task. On the other hand, in the linguistic memory branching task, the reaction time in the mismatch condition (task sequence C) tends to be faster than the reaction time in the mismatch condition (task sequence D), and the fatigue level is higher as this tendency becomes weaker . From this result, it is inferred that in the linguistic memory branching task, the strength of attention to the mismatch condition of the inserted cautionary task worked in the direction of promoting the processing of the linguistic memory task. Although the cause cannot be identified, the result is likely to reflect the sharpness of attention control caused by the condition of the attention task (difference between coincidence and inconsistency) as in the spatial memory branching task.

  To summarize the general tendency found from this experiment, the reaction time for the spatial memory task for storing the position of the figure is delayed by inserting an attention task (mismatch condition) for determining the orientation of the figure. On the other hand, in a linguistic memory task that stores phonological information of a language, the reaction time becomes fast. It was shown that the higher the degree of fatigue, the weaker these general trends. Here, because the linguistic memory task used in this experiment is related to the shape recognition process of characters (katakana), the figure memory branching task for storing the shape of the figure is the same as the linguistic memory branching task. The result is considered to be obtained.

  In any case, as described above, the fatigue level of the subject can be quantitatively evaluated by using the reaction time index (the mismatch condition and the match condition) of each branching task. In the case of a spatial memory branching task, the fatigue level increases as the index value decreases, and in the case of a linguistic branching task, the fatigue level increases as the index value increases.

  FIG. 9C is a correlation diagram between the difference in the reaction time index between the spatial memory task and the linguistic memory task and the fatigue score measured with the questionnaire.

  The fatigue level can be evaluated by using any one of the tasks alone, but it is effective to create a composite index using two blanching tasks in order to increase the accuracy. As shown in FIG. 9C, when a new reaction time index is created by subtracting the reaction time index in the spatial memory branching task from the reaction time index in the linguistic memory branching task, the correlation with the fatigue level is higher. (Correlation coefficient 0.68).

  In the present invention, using these phenomena, a response to the cognitive task is acquired by key input or the like, and the fatigue level of the subject is calculated and displayed from the response time.

Spatial memory branching task (matching condition) reaction time is A, spatial memory branching task (mismatching condition) reaction time is B, linguistic memory branching task (matching condition) reaction time is C, linguistic Assuming that the reaction time of the memory blanching task (mismatch condition) is D, there are examples of the following equations (1) to (11) as the calculation formula of the reaction time index (R).
R = BA (1)
R = (B−A) / | B + A | (2)
R = D-C (3)
R = (D−C) / | D + C | (4)
R = (DC)-(BA) (5)
R = {(DC)-(BA)} / {(DC) + (BA)} (6)
R = B / A (7)
R = D / C (8)
R = (D / C) / (B / A) (9)
R = (D / C)-(B / A) (10)
R = (DC) / (BA) (11)
The fatigue index calculation formulas shown in the above formulas (1) to (6) and formula (11) are the reaction time when the attention task of the mismatch condition is inserted, and the reaction time when the attention task of the matching condition is inserted. Based on the difference. The fatigue index calculation formulas shown in the above formulas (7) to (10) are based on the ratio between the reaction time when the attention task with the mismatch condition is inserted and the reaction time when the attention task with the matching condition is inserted. Yes.

  The fatigue index calculation formulas shown in the above formulas (5), (6), and (11) are the reaction times for the linguistic memory task when the attention task with the mismatch condition is inserted and when the attention task with the matching condition is inserted. And the difference in the reaction time for the spatial memory task when the attention task with the mismatch condition is inserted and when the attention task with the matching condition is inserted. The fatigue index calculation formulas shown in the above formulas (2), (4), and (6) are based on a value obtained by dividing the difference in reaction time by the sum of reaction times.

  The fatigue index calculation formulas shown in the above equations (9) and (10) are inconsistent with the ratio of the reaction time to the linguistic memory task when the attention task with the mismatch condition is inserted and when the attention task with the matching condition is inserted. It includes both the ratio of the reaction time to the spatial memory task when the attention task of the condition is inserted and the attention task of the matching condition is inserted.

  Other effective indexes can be created by further modifying the above equations such as standardization with reference data. The important point is to extract the difference between the match condition and the mismatch condition.

  The relationship between the type and difficulty of the cognitive task, the condition of the subject, and the desired calculation formula is stored in advance in the storage means, and when a measurement parameter is given at the initial setting stage, multiple candidates are presented on the display screen The subject or the experimenter may be able to select the calculation formula. For example, when it is assumed from the given measurement parameters that the difference in reaction time within the measurement range is relatively small, an equation based on the difference in reaction time is used, and the difference in response time is assumed to be relatively large It is conceivable to use a formula based on a ratio or a formula based on a combination of a difference and a ratio.

  10 shows R = (D−C) − (B−A) of the above formula (5) as a calculation formula, that is, using the result of the correlation diagram shown in FIG. Based on the difference in the response time index of the memory task, an example is shown in which the state of the subject's fatigue level is determined by being classified into “good”, “mild fatigue”, and “severe fatigue”.

  Note that the memory task and the attention task are not limited to being presented visually, and may be presented by auditory stimulation. For example, the items corresponding to the memory task and the attention task in the above examples may be converted into auditory stimuli and presented.

  According to the present invention, it is possible to record a reaction to a cognitive task and to measure and feed back a fatigue level objectively and quantitatively by software operating on an existing electronic device such as a PC or a mobile phone. That is, by utilizing a subtle difference in reaction time, it is possible to prevent the subject from intentionally manipulating the fatigue value. Moreover, since it can measure simply on PC, a special apparatus is not required and it can introduce at low cost. Moreover, since it can be implemented in a short time using a simple task, the subject can easily check the fatigue level during daily office work or at home. Furthermore, since it can implement without using the image and phrase related to "fatigue", the fatigue index in a natural mood state of a subject can be obtained.

  A fatigue evaluation system according to a second embodiment of the present invention will be described with reference to FIGS. The basic form of the system configuration of the present embodiment is the same as that of the first embodiment, and as shown in FIG. 1, storage means for storing a cognitive task, answer data from a subject, information necessary for calculating a fatigue index, etc. Control means for controlling each process, calculation means for calculating a fatigue index, etc., presenting means for presenting a subject to a subject, etc., and input means for receiving input from the subject or an experimenter.

Hereinafter, system processing will be described with reference to FIGS.
An overall flowchart of this system is shown in FIG. First, an initial setting for information necessary for measuring the degree of fatigue is received (S1100). In implementation, a preset parameter may be automatically used, but an experimenter can also set a parameter through an input means.
Examples of the setting screen 400 are shown in FIGS. 12A to 12C. First, an example of the setting items of the stimulus presentation parameters on the setting screen 400 is shown in FIG. 12A.
Start timing: Set the timing (timing to start the program) to perform fatigue evaluation. When the 901 “manual” button is selected, the system is activated when the experimenter or the subject performs an action such as pressing the start button. In addition, when the 902 “automatic” button is selected, it is automatically activated at the time interval set in 903 (in this example, 120 minutes).

  Memory task: Set the memory task type, difficulty level, and number of repetitions. The type of the storage task is selected from the storage tasks stored in the storage unit in advance using the pull-down menu 904. Next, the difficulty level of the selected memory task is set by selecting one of the “Low”, “Medium”, and “High” buttons 905 to 907. Reference numeral 908 denotes an input unit for the number of repetitions of the storage task. Here, an example is shown in which the difficulty level is selected from “low”, “medium”, and “high”, but it is also possible to set the difficulty level more finely, such as 5 levels, 10 levels, or each task condition. If the task is difficult and cannot be done, or if it is too simple and you do not have to think too much, it is expected that the target fatigue index will not be obtained, so adjust to the appropriate difficulty level according to the subject's level Is important.

  In addition, a method of automatically adjusting to an optimum difficulty level by performing a preliminary test is also effective. In this case, the difficulty level is set based on a criterion such that the correct answer rate is equal to or higher than a predetermined value or the average value of the reaction time is within a predetermined range. The difficulty level is adjusted, for example, by changing the type and number of figures serving as the target stimulus of the memory task, the length of the memory time, and the like.

  Finally, the number of repetitions of the storage task is input to 913 and set. This determines how many times the memory task for each condition is executed. Theoretically, as the number of repetitions increases, stable and reliable data can be acquired. However, as the number of repetitions increases, the time required increases and the load on the subject increases. It is also possible to automatically set the optimum number of repetitions, such as continuing the repetition until the variation in the reaction time falls within a certain range.

  Attention (insertion) task: Set the type, difficulty level, and number of repetitions of the attention task to be inserted into the memory task. The type of the attention task is selected from the attention tasks stored in the storage means in advance using the pull-down menu 909. Next, the difficulty level of the selected attention task is set by selecting one of the “low”, “medium”, and “high” buttons 910 to 912 in the same manner as the memory task. Finally, the number of repetitions of the attention task is input and set in 913. Since the number of repetitions of the attention task is limited by the storage time of the storage task, there are cases where a numerical value that cannot be executed cannot be input.

  Next, FIG. 12B shows the setting items for the reaction acquisition parameters. The “effective reaction time”, which is the effective range of the reaction time adopted as data, is set by inputting the minimum value to the input unit 914 and the maximum value to 915. The “effective time difference”, which is the effective range of the reaction time difference between tasks, is set by inputting a maximum value to the input unit 916. This is because you can get more reliable results by not adopting fast reaction time data that you might have pushed and hit, or slow reaction time data that you might have failed to reach the answer to the task well. It is a device for obtaining. It also has a role of detecting an intentional reaction time operation.

Finally, a selection screen for items to be fed back to the subject is shown in FIG. 12C. Here, an example is shown in which one of the button 917 for displaying only the fatigue index (score) and the button 918 for displaying a comment determined from the fatigue index is selected.
The fatigue index calculation formula and the fatigue index value to comment conversion table are read from the setting file input in 919 (FIG. 13). In the example of the setting file in FIG. 13, an example of a setting file that displays three-stage fatigue level comments according to the calculated fatigue level index using the reaction time index that showed the effect in FIG. 9C as an index calculation formula is shown. . That is, when the fatigue index is less than −500, “good”, 250 or more are determined as “heavy fatigue”, and “light fatigue” is determined between them, and a corresponding comment is displayed. In addition, the number of these divisions and the index value for the division are examples, and may be set as appropriate according to the application.

  Returning to FIG. 11, when the activation timing is set to “manual”, the fatigue evaluation system starts presenting a task immediately after the start button is pressed or a predetermined operation is performed (S1102, S1106, S1108). .

  When the activation timing is set to “automatic”, the task presentation starts when the set time (120 minutes in the example of FIG. 12) has elapsed (S1102, S1104, S1108).

  FIG. 14 shows an example of the task presentation process (S1110). The cognitive task to be performed is a memory task consisting of a target stimulus (S1112) for memorizing the position and language of the figure, a probe stimulus (S1124, S1126) for testing the memory after a predetermined time, and a feature of the presented stimulus such as the direction of the arrow. This is a branching task composed of two types of tasks, the attention task (S1114 to 1122). The response to the attention task (answer and response time) is recorded in the caution memory data (S1118), and the response to the memory task (answer and response time) is recorded in the memory task data (S1128). The number of executions of the branching task (memory task) is counted as n, and the number of executions of the attention task performed in each branching task is counted as m, which are repeated until reaching the specified number (S1130, S1132).

  The number of executions n of the branching task used for calculating the fatigue index is a plurality of times in order to obtain a stable average value under each condition. Although it can be performed once, the reaction time may be delayed or increased accidentally, so it is desirable to repeat at least three times. However, if the number of repetitions increases, the measurement time becomes longer and the burden on the subject increases. Therefore, it is necessary to suppress the number of times so as not to lose the simplicity that is an advantage of the present invention.

  On the other hand, the execution number m of the attention task basically depends on the length of the period in which the memory is retained in the memory task. In general, in a delay matching task for recognizing stored information, the storage retention time is often set to about 1 to 12 seconds. Since the holding period for optimizing the degree of difficulty differs depending on the information to be stored or the subject, it is difficult to determine the optimal setting time in general, but here it is performed as 7 seconds. If there are seven seconds, it is possible to carry out the attention task of determining the direction of the arrow about three times. As described above, the number of attention tasks is set comprehensively in consideration of the retention time of the memory task, the difficulty level of the memory task and the attention task, the setting conditions, and the like. The attention task is a cognitive task that makes some judgment regarding the characteristics of the presented stimulus, and a discrepancy condition including an element that disturbs the judgment (causes cognitive interference) and an element that disturbs the judgment (causes cognitive interference) There are two conditions of matching conditions that do not include. It is desirable to implement each condition at the same frequency and in an irregular order.

  As a modification of the second embodiment, FIG. 15 shows a flowchart of the task presentation process similar to that of FIG. The difference from FIG. 14 is that the number of executions n of the branching task is determined based on the number of successful trials (S1134 to S1138). The successful trial here is a case where the response of the subject coincides with the previously set answer and the reaction time is within the set range. If the answer is incorrect or the response is slower than usual, it is considered unsuitable for the calculation of the fatigue index. Is valid. Of course, it is also possible to use failure trial data such as wrong answers in calculating the fatigue index.

  Returning to FIG. 11, when the task presentation process (S1110) ends, the fatigue evaluation system next executes a fatigue index calculation process (S1140).

An example of the fatigue index calculation process is shown in FIG. First, a fatigue level calculation formula is read from the setting file (FIG. 13) (S1142 to S1144). Next, the storage task data acquired in the task presentation process is read line by line (for each trial) (S1146 to S1148). When the answer is correct and the reaction time is within the set range (S1150 to S1162), the answers are classified for each condition of A to D and added to each condition data (FIGS. 3 to 6).
A: Spatial memory task and branching task of attention task with matching condition B: Spatial memory task and branching task of attention task with inconsistent condition C: Branching task of linguistic memory task and attention task with matching condition D: Branching task of linguistic memory task and attention task of discrepancy condition After reading up to the last data line, calculate the average value of reaction time in each condition, and use that value to calculate the fatigue index according to the fatigue level calculation formula Calculate (S1164 to S1166).

  Returning to FIG. 11, the fatigue evaluation system displays the result according to the feedback setting (S1170). When the feedback is only the fatigue index, the fatigue index is displayed as it is with numerical values, colors, graphs, etc. (S1172). When both the fatigue index and the comment or only the comment is fed back, the fatigue index is converted into a comment according to the setting file and displayed (S1174 to S1180).

  17A to 17C show examples of feedback display screens. (A) and (B) of FIG. 17A show a case where only the fatigue index is displayed, and the fatigue index is fed back by numbers and / or graphs, colors, and the like. 17A and 17B show a case where a comment converted from a fatigue index is displayed, and a comment, a figure, a picture, etc. obtained from the conversion table are fed back. (A) and (B) in FIG. 17C show the case where both the fatigue index and the comment are displayed.

  According to the present embodiment, there are the same effects as in the first embodiment.

  A fatigue evaluation system according to a third embodiment of the present invention will be described with reference to FIG. The basic form of this embodiment is the same as that of Embodiments 1 and 2, and this system is realized on an existing electronic device such as a PC or a mobile phone, and the fatigue level of the subject is evaluated and fed back. In this embodiment, the fatigue evaluation system 100 described in Embodiments 1 and 2 has a function of recording (logging) a fatigue index of the same subject over time and displaying it as a time-series change. In particular, in addition to the fatigue index shown in the present invention, other biological information (the previous day's sleep time, meal time, blood pressure, heart rate, biological fluctuation information) is measured and displayed, and overtime hours and other special events are also combined. It has a recording function. These are effective in monitoring the degree of individual fatigue.

  According to the present embodiment, there is an effect that by monitoring the degree of individual fatigue, the probability of daily fatigue or mistakes can be estimated and utilized for adjustment of future work contents.

  As part of labor management in a company, an occupational physician (or an equivalent person in charge of health management in the company, hereinafter simply referred to as an occupational physician) may be involved in managing the working conditions of employees. For example, it is conceivable that an industrial physician grasps the health status and working status of individual employees and provides health guidance to long-time workers. As a fourth embodiment of the present invention, a fatigue level evaluation system for an industrial physician to calculate and evaluate the mental fatigue level of employees in a company will be described with reference to FIGS.

FIG. 19 is a schematic diagram showing the configuration of an in-company fatigue evaluation system according to the fourth embodiment of the present invention.
An in-house fatigue level evaluation system 1500 includes a health management server 1501, a work management server 1502, an in-house organization database 1503, an industrial physician terminal 1504, employee terminals 1505 (A to N), and a workplace manager terminal 1506. The internal communication network 1507 can be connected to each other. Each of the terminals 1504 to 1506 is provided with a camera 1508 and voice input / output means (not shown), and can communicate with each other by an e-mail and send / receive photos and videos between an industrial physician and an employee or manager thereof. It is assumed that The storage means of the health management server 1501 stores the fatigue evaluation program described in the first to third embodiments and various data necessary for executing this program. Employees and managers can access and execute. The health management server 1501 may include information such as personal blood pressure and overtime hours described in the third embodiment. In addition, the industrial physician, individual employees, and managers can access various databases such as the health management server 1501, the work management server 1502, and the in-house organization database 1503 based on a predetermined level of access authority.

  FIG. 20 is a flowchart showing the entire processing of the fourth embodiment of the present invention. The occupational physician selects the subject of the fatigue degree diagnosis by the diagnosis request from the employee (S2010), the diagnosis request from the administrator (S2011), or the extraction process (S2012) of the industrial physician himself (S2020). ). Then, the employee is diagnosed using e-mail or a camera (S2021), and if there is a positive response from the employee (S2022), the degree of fatigue is diagnosed. First, optimal parameters for diagnosis are set based on information about the target employee (S2023), and the employee is diagnosed by the fatigue evaluation program based on the setting (S2024). In order to perform the diagnosis process smoothly, it is desirable to use the terminal in a room dedicated for diagnosis. When the occupational physician is diagnosed as “severe fatigue” based on the diagnosis result, he / she generates advice, contacts the employee or manager, takes necessary actions (S2024), and sends the result to the health management server. 1501 is recorded (S2025).

  Thus, it is effective to configure the fatigue evaluation program of the present invention as an in-house system, manage employee data collectively, and use it for health management by an industrial physician. According to the present embodiment, the fatigue level of an employee can be objectively and quantitatively evaluated on a daily basis with a simple and inexpensive system, and the fatigue index and / or the evaluation result is fed back to the employee. It can be used to support efficient business operations, such as prompting breaks appropriately. In addition, it is possible to provide a system that can easily measure and display an objective and quantitative index representing mental fatigue, which is effective in preventing human error in the workplace and improving mental health. That is, according to the present embodiment, an objective and quantitative index can be provided with a simple device configuration, so that an industrial physician can accurately grasp the state of mental fatigue of employees and take necessary measures. Can do. If the use of the fatigue assessment program is left to the individual employee's self-judgment, there may be a situation in which the situation becomes severe without being aware of mental fatigue due to work, but it is an in-house system and individual employees are organized. Such a situation can be prevented by creating a system that can be managed and supported in an efficient manner.

DESCRIPTION OF SYMBOLS 100 ... Fatigue degree evaluation system, 101 ... Input means, 102 ... Control means, 103 ... Presentation means (display means), 104 ... Calculation means, 105 ... Storage means, 106 ... Output means, 107 ... Communication means, 120 ... Subject, 301: Target stimulation example of spatial memory task, 302-304 ... Attention task example of matching condition, 305 ... Example of probe stimulation of spatial memory task, 400 ... Display screen, 402 ... Presentation screen of task sequence, 404 ... Task sequence 406 ... icon for subject's answer operation, 408 ... operation button, 410 ... numeric keypad, 501 ... target stimulation example of spatial memory task, 502-504 ... attention task example of mismatch condition, 505 ... space Example of probe stimulation of sex memory task, 601... Target stimulation example of language memory task, 602 to 604. 605 ... probe stimulation example of linguistic memory task, 701 ... target stimulation example of linguistic memory task, 702-704 ... notice task example of mismatch condition, 705 ... probe stimulation example of linguistic memory task, 901: Radio button for setting activation timing to manual, 902: Radio button for automatically setting activation timing, 903: Input section for interval time (minute) of activation timing, 904: Pull-down menu for selecting the type of memory task, 905: Radio button for setting the difficulty level of the memory task to “low”, 906: Radio button for setting the difficulty level of the memory task to “medium”, 907: Radio button for setting the difficulty level of the memory task to “high” 908: Input section for the number of repetitions of the memory task, 909: Pull-down menu for selecting the type of attention task, 910: Difficulty of attention task A radio button for setting the difficulty level of the attention task to “medium”, 912. A radio button for setting the difficulty level of the attention task to “high”, 913. Number of times input part 914 ... Input part of minimum value of effective reaction time, 915 ... Input part of maximum value of effective reaction time, 916 ... Input part of maximum value of effective time difference, 917 ... Fatigue index is selected as feedback information Radio button, 918 ... Radio button for selecting a comment for feedback information, 919 ... Setting file selection unit, 1500 ... In-house fatigue level evaluation system, 1501 ... Health management server, 1502 ... Work management server, 1503 ... In-house organization database, 1504 ... Industrial physician terminal, 1505 (A to N) ... Employee terminal, 1506 ... Workplace manager terminal.

Claims (20)

Presenting means for presenting the subject to the subject;
Input means for receiving a response from the subject;
Storage means for storing a task sequence and a fatigue index calculation formula based on the task sequence;
A calculation means for calculating the degree of fatigue;
An output means for outputting the evaluation result of the fatigue degree;
Control means,
The task sequence is composed of a combination of at least a memory task that requires memory and a caution task that is inserted between presentation of the memory task and requires attention;
The control means presents the task sequence to the presenting means, stores an answer and a response time as the response to the task sequence in the storage means, and based on the fatigue index calculation formula from the answer and the reaction time A fatigue evaluation system characterized by causing the calculation means to calculate a fatigue index and outputting a fatigue evaluation result based on the fatigue index to the output means. In claim 1,
The fatigue evaluation system, wherein the attention task includes at least two conditions: a mismatch condition designed to cause cognitive interference and a match condition designed not to cause cognitive interference. In claim 2,
The fatigue index calculation formula uses the reaction time for the memory task,
Fatigue degree characterized by evaluating the degree of fatigue using a difference between the reaction time when the attention task of the mismatch condition is inserted and the reaction time when the attention task of the matching condition is inserted Evaluation system. In claim 2,
The fatigue index calculation formula uses the reaction time for the memory task,
Fatigue degree characterized by evaluating the fatigue level using a ratio between the reaction time when the attention task of the mismatch condition is inserted and the reaction time when the attention task of the matching condition is inserted Evaluation system. In claim 1,
The memory task includes a target stimulus for storing the position, shape, language, etc. of a figure,
A probe stimulus that tests its memory after a predetermined time,
The fatigue evaluation system characterized by acquiring the said reaction time with respect to the said probe stimulus based on the response from the said input means. In claim 1,
Fatigue level evaluation system characterized in that the memory task includes one or both of a linguistic memory task using a phonological loop for storing and a spatial memory task not using a phonological loop for storing . In claim 2,
The fatigue evaluation system characterized in that the memory task includes one or both of a graphic shape memory task for storing the color and shape of a graphic and a spatial memory task for storing the position of the graphic. In claim 2,
When the fatigue index calculation formula is inserted, when the attention task of the mismatch condition is inserted and when the attention task of the matching condition is inserted, the difference in reaction time with respect to the linguistic memory task, and when the attention task of the mismatch condition is inserted And a difference in reaction time with respect to a spatial memory task when the attention task of the matching condition is inserted. In claim 2,
The fatigue index calculation formula is obtained when the attention task of the mismatch condition is inserted and when the attention task of the matching condition is inserted and the ratio of the reaction time to the linguistic memory task and the attention task of the mismatch condition is inserted And a ratio of the reaction time with respect to the spatial memory task when the attention task of the matching condition is inserted. In claim 1,
The fatigue index evaluation system is characterized in that the fatigue index is calculated using only a response time when a correct answer rate or a reaction time for the memory task and the attention task is within a predetermined range. In claim 1,
The fatigue index evaluation system characterized in that the fatigue index is calculated using only the response time when the correct answer rate and the reaction time are within a predetermined range for the memory task and the attention task. In claim 1,
The fatigue evaluation system, wherein the memory task and the attention task are presented by visual stimulation. In claim 1,
The fatigue evaluation system, wherein the memory task and the attention task are presented by auditory stimulation. In claim 1,
The fatigue evaluation system, wherein the input unit, the presentation unit, and the output unit have a common display screen having a GUI function. In claim 14,
The control means has a function of recording the fatigue index of the same subject over time and displaying it on the display screen as a time series change. A health management server configured to be mutually connectable via an in-house communication network, an industrial physician terminal, an employee terminal, and an administrator terminal;
Each terminal includes a presenting unit for presenting a task, an input unit for receiving a response to the presenting of the task, a storage unit for storing a task sequence and a fatigue index calculation formula based on the task sequence, and a fatigue degree calculation process Calculation means for performing, output means for outputting the evaluation result of fatigue, and control means,
The task sequence is composed of a combination of at least a memory task that requires memory and a caution task that is inserted between presentation of the memory task and requires attention;
The industrial physician terminal has a function of accessing a database of the health management server to extract information on employee health management, and selecting a subject for diagnosis of fatigue level,
The control means of the industrial physician terminal sets optimum parameters for the diagnosis of the employee, causes the presentation means of the employee terminal to present the task sequence, and the response of the employee to the task sequence The answer and the reaction time are stored in the storage means, and the calculation means is calculated based on the fatigue index calculation formula from the answer and the reaction time, and the fatigue level of the employee based on the fatigue index is calculated. An in-house fatigue level evaluation system configured to record an evaluation result in a health management server and output the evaluation result to the employee terminal and the administrator terminal. In claim 16,
The in-company fatigue evaluation is characterized in that the attention task includes at least two conditions: a mismatch condition designed to cause cognitive interference and a match condition designed not to cause cognitive interference. system. A fatigue evaluation method using a fatigue evaluation system,
The fatigue evaluation system includes a presentation unit that presents a task to a subject, an input unit that receives a response from the subject, a task sequence, and a fatigue index calculation formula based on the task sequence A means for calculating the fatigue level, an output means for outputting the evaluation result of the fatigue level, and a control means.
The task sequence is composed of a combination of at least a memory task that requires memory and a caution task that is inserted between presentation of the memory task and requires attention;
Presenting the task sequence to the presenting means,
Storing the response and response time of the subject as a response to the task sequence in the storage means;
Fatigue index is calculated by the calculation means based on the fatigue index calculation formula from the response and reaction time,
A fatigue level evaluation method, comprising: outputting the fatigue level evaluation result based on the fatigue index to the output means. In claim 18,
The memory task includes a target stimulus that requires memory, and a probe stimulus that tests memory related to the target stimulus after a predetermined time,
The attention task consists of at least two conditions: a mismatch condition designed to cause cognitive interference and a match condition designed not to cause cognitive interference;
After presenting the target stimulus, present the attention task, store the response as a response of the subject to the attention task and the reaction time in the storage means,
Presenting the probe stimulus after the predetermined time, storing the response as a response of the subject to the injection probe stimulus and the reaction time in the storage means,
The fatigue index evaluation method, wherein the fatigue index is calculated by the fatigue index calculation formula using the reaction time for the memory task. In claim 19,
The fatigue index includes a difference or ratio of reaction time with respect to the linguistic memory task when the attention task of the mismatch condition is inserted and when the attention task of the matching condition is inserted, and the attention task of the mismatch condition is inserted The fatigue level evaluation method is calculated using both the difference or the ratio of the reaction time with respect to the spatial memory task when the attention task of the matching condition and the attention task is inserted.

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