JP4611453B1 - Method and apparatus for measuring vibration sensation threshold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration sensation threshold measurement method capable of improving measurement accuracy while conforming to the vibration sensation threshold measurement method specified in Non-Patent Document 1 or Non-Patent Document 2.
SOLUTION: The ascending method for obtaining the ascending method threshold by gradually increasing the magnitude of the vibration stimulus until the subject responds, and the vibration sense threshold at the fingertip until the subject's response disappears. In the vibration sensation threshold measurement method obtained by repeating the descending method to obtain the descending method threshold by gradually decreasing the magnitude, the magnitude of the vibration stimulus at the start of the ascending method is the descending method threshold obtained by the immediately preceding descending method. Is set to be randomly changed within a predetermined range (for example, 0 to -10 dB). Furthermore, a stop time of vibration stimulation is provided in step SP9 after the measurement by the descending method is completed and the measurement by the ascending method is started. The stop period may be changed randomly within a predetermined range (for example, 0 to 2 seconds).
[Selection] Figure 3

Description

  The present invention relates to a vibration sensation threshold measurement method and apparatus for measuring a vibration sensation threshold (VPT) at a fingertip by repeating an ascending method and a descending method.

  A method for measuring the vibration sensation threshold at the fingertip is defined in Non-Patent Document 1 or Non-Patent Document 2. An ascending / descending method is known as a method for measuring the vibration sensation threshold at the fingertip. The ascending / descending method is a psychophysical measurement method in which two limit thresholds are automatically measured by giving the subject repeated repetition stimuli of different magnitudes in a short time.

In this method, until the subject perceives the vibration stimulus, the skin stimulation is applied to the skin so that the magnitude of the vibration stimulus continuously increases. This is a method of obtaining two threshold values by combining a descending method of obtaining a threshold value by giving a vibration stimulus whose skin vibration magnitude continuously decreases until it is no longer perceived.

That is, the subject is in a state where the push button switch is pressed while feeling the vibration stimulus, and is in a state where the push button switch is not pushed while not feeling the vibration stimulus. The inspection device reduces the magnitude of the vibration stimulus while the pushbutton switch is pressed, and increases the magnitude of the vibration stimulus while the pushbutton switch is not pressed. Measure the rising method threshold to start feeling and the falling method threshold to stop feeling vibration stimulus.

ISO 13091-1 (2003) JIS B7763-1 (2009)

However, when the vibration sensation threshold is measured by the ascending / descending method defined in Non-Patent Document 1 or Non-Patent Document 2, the rate of increase / decrease of the vibration stimulus is constant. In response to this, the pushbutton switch is operated, which causes a false response.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is compatible with the vibration sensation threshold measurement method defined in Non-Patent Document 1 or Non-Patent Document 2. However, it is an object of the present invention to provide a vibration sensation threshold value measuring method and apparatus capable of improving measurement accuracy.

In order to solve the above-mentioned problem, the invention according to claim 1 is directed to an ascending method for obtaining an ascending method threshold by gradually increasing the magnitude of the vibration stimulus until a subject's response is obtained. In the vibration sensation threshold measurement method obtained by repeating the descending method for gradually decreasing the magnitude of the vibration stimulus until the examiner's response disappears and obtaining the descending method threshold, the magnitude of the vibration stimulus at the start in the ascent method is The descending method threshold obtained by the immediately preceding descending method is set by randomly changing within a predetermined range (for example, 0 to -10 dB).

According to a second aspect of the present invention, in the vibration sensation threshold value measuring method according to the first aspect, the vibration stimulation stop period is between the end of the measurement by the descending method and the start of the measurement by the ascent method. It is provided.

  According to a third aspect of the present invention, in the vibration sensation threshold value measuring method according to the second aspect, the stop period is set by changing randomly within a predetermined range (for example, 0 to 2 seconds).

  The invention according to claim 4 is the ascending method for obtaining the ascending method threshold by gradually increasing the magnitude of the vibration stimulus until the subject's response is obtained, and the subject's response. In the vibration sensation threshold value measurement device that is obtained by repeating the descending method for obtaining the descending method threshold value by gradually decreasing the magnitude of the vibratory stimulus until there is no more, the magnitude of the vibration stimulus at the start in the ascending method is An ascending method start level setting means is provided which is set by randomly changing within a predetermined range (for example, 0 to -10 dB) with respect to the descending method threshold obtained by the method.

  According to a fifth aspect of the present invention, in the vibration sensation threshold value measuring device according to the fourth aspect, the period of the vibration stimulation is stopped after the measurement by the descending method is finished and the measurement by the ascent method is started. Timer means for setting is provided.

  According to a sixth aspect of the present invention, in the vibration sensation threshold value measuring apparatus according to the fifth aspect, the stop period set in the timer means is set by changing randomly within a predetermined range (for example, 0 to 2 seconds). Is.

  The invention according to claim 7 is the vibration sensation threshold value measuring apparatus according to any one of claims 4 to 6, wherein the vibration sense threshold value is calculated by calculating an average value of the ascending method threshold value and the descending method threshold value. A sensory threshold value calculation unit is provided, and an evaluation unit is provided for evaluating whether or not the vibration sensory threshold value calculated by the vibration sensory threshold value calculation unit is consistent in response.

  According to an eighth aspect of the present invention, in the vibration sensation threshold value measuring apparatus according to any one of the fourth to seventh aspects, information relating to the magnitude of the vibration stimulus is not displayed on the screen during the measurement.

According to the first aspect of the present invention, the magnitude of the vibration stimulus at the start of the ascending method changes randomly within a predetermined range (for example, 0 to −10 dB) with respect to the descending method threshold obtained by the immediately preceding descending method. Therefore, the measurement accuracy can be improved by reducing erroneous responses.

  According to the second aspect of the present invention, since the period for stopping the vibration stimulation is provided between the end of the measurement by the descending method and the start of the measurement by the ascending method, the subject responds at regular intervals. Measurement accuracy is improved.

  According to the invention of claim 3, since the timer means for setting the vibration stimulation stop period at random within a predetermined range (for example, 0 to 2 seconds) is provided, the subject responds at regular intervals. Measurement accuracy is improved.

  According to the invention of claim 4, the magnitude of the vibration stimulus at the start of the ascending method is randomly changed within a predetermined range (for example, 0 to -10 dB) with respect to the descending method threshold obtained by the immediately preceding descending method. Since the ascending method start level setting means for setting is provided, erroneous response can be reduced and measurement accuracy can be improved.

  According to the fifth aspect of the present invention, since the timer means for setting the stop period of the vibration stimulation is provided between the end of the measurement by the descending method and the start of the measurement by the ascending method, Since it is impossible to respond at regular intervals, measurement accuracy is improved.

  According to the invention according to claim 6, since the stop period set in the timer means is changed randomly within a predetermined range (for example, 0 to 2 seconds), the subject responds at regular intervals. Measurement accuracy is improved.

  According to the invention of claim 7, there is provided vibration sensation threshold value calculating means for calculating the vibration sensation threshold value by calculating an average value of the ascending method threshold value and the descending method threshold value, and whether or not the vibration sensation threshold value is consistent in response. Since the evaluation means for evaluating is provided, a reasonable evaluation can be obtained with respect to the consistency of the response of the vibration sensation threshold value, so that the reliability of the vibration sensation threshold value can be ensured.

According to the eighth aspect of the present invention, the information related to the magnitude of the vibration stimulus is not displayed on the screen during the measurement, so that the reliability of the vibration sensation threshold can be ensured.

Block diagram of a vibration sensation threshold value measuring apparatus according to the present invention Explanatory diagram of vibration sensation threshold measurement method by ascending method and descending method The flowchart which shows the procedure of the vibration sensation threshold value measuring method which concerns on this invention

  As shown in FIG. 1, a vibration sensation threshold value measuring apparatus according to the present invention includes an apparatus main body 1 including an operation unit, a display unit, a drive circuit, a storage unit, and the like, and a support for supporting a subject's forearm during measurement. A table (not shown), an exciter 2 that applies a vibration stimulus to the fingertip of the subject based on a command from the apparatus main body 1, and a push that the subject presses while feeling the vibration stimulus by the shaker 2 It consists of a button switch 3.

The apparatus body 1 also includes a control unit 11, a signal generation unit 12, an attenuator 13, an amplifier 14, an A / D converter 15, an operation switch 16, a built-in printer 17, a liquid crystal display 18, a vibration stimulation level dial 19, and the like. ing.

The control unit 11 controls the entire apparatus and stores various data. The signal generation unit 12 generates a vibration signal for the vibrator 2. The A / D converter 15 converts the output signal of the load cell 4 from the vibrator 2 and the output signal of the accelerometer 5 into digital signals. The operation switch 16 generates a start signal and sets various setting values. The built-in printer 17 outputs measurement results and the like. The liquid crystal display 18 displays various data and measurement results. The vibration stimulation level dial 19 is used to manually change the magnitude of vibration stimulation.

Further, the control unit 11 includes an ascending method start level setting means 21 for determining a level at the start of the ascending method, and a timer means 22 for stopping the vibration stimulation from the end of the descending method to the start of the ascending method. And a vibration sensation threshold value calculation means (VPT calculation means) 23 for calculating an average value of the ascending method threshold value and the descending method threshold value to obtain a vibration sensation threshold value (VPT), and whether the vibration sensation threshold value is consistent in response. Evaluation means 24 is provided for evaluating.

Then, the vibration sensation threshold value measuring apparatus uses the timer means 22, the vibration sensation threshold value calculation means 23, the evaluation means 24, and the like to gradually increase the magnitude of the vibration stimulus until the subject's response is received. The vibration sensation threshold value at the fingertip of the subject is calculated by repeating the ascending method for obtaining the descent method and the descent method for obtaining the descent method threshold value by gradually decreasing the magnitude of the vibration stimulus until the subject no longer responds.

  A vibration sensation threshold value measuring method using the ascending method and the descending method using the vibration sensation threshold value measuring apparatus configured as described above will be described. Here, the number of repetitions is three, but is not limited. First, as shown in FIG. 2 and FIG. 3, in step SP1, training is performed so that the subject can get used to the vibration sensation threshold measurement. When the subject's fingertip is set on the vibrator 2, the measurement is started, and the magnitude of the vibration stimulus by the vibrator 2 gradually increases at a predetermined change rate (for example, 3 dB / second).

In the process of increasing the magnitude of the vibration stimulus, the subject presses the push button switch 3 when the level ta (0) at which the vibration stimulus is felt. Press and hold. When the push button switch 3 is pressed (ON state), the magnitude of the vibration stimulus changes from increasing to decreasing, and while the push button switch 3 is being pressed (ON state), the magnitude of the vibration stimulus is a predetermined change rate. It gradually decreases at (for example, 3 dB / second). When the push button switch 3 is stopped when the subject no longer feels vibration stimulation (OFF state), the level at this point is stored in the control unit 11 as td (0), and the training is ended. However, the training may be performed several times for the subject to get used to.

  Next, vibration sensation threshold measurement starts from step SP2. The vibration stimulation is stopped (for example, for 1 second) by the timer means 22 between the end of the training and the measurement by the first ascending method. And when the stop period of vibration stimulation passes, the measurement by the 1st ascent method is started. The vibration stimulation start level S1 at this time is set to a level td (0) when the pushbutton switch 3 is turned off by training. Or it may be a sufficiently lower level. When the measurement is started, the magnitude of the vibration stimulus by the vibrator 2 gradually increases at a predetermined change rate (for example, 3 dB / second).

Next, in step SP3, it is determined whether or not the push button switch 3 is turned on (response is received). If it is determined that the pushbutton switch 3 is not in the ON state, the process returns to step SP2 to gradually increase the magnitude of the vibration stimulus at a predetermined change rate (for example, 3 dB / second). On the other hand, when it is determined that the pushbutton switch 3 is turned on, in step SP4, the magnitude of the vibration stimulus when the pushbutton switch 3 is turned on is set as the first rising method threshold ta (1). It is stored in the control unit 11.

  Next, in step SP5, the magnitude of the vibration stimulus changes from increase to decrease, and while the pushbutton switch 3 is in the ON state, the magnitude of the vibration stimulus is gradually reduced at a predetermined change rate (for example, 3 dB / second). To go.

Next, in step SP6, it is determined whether or not the push button switch 3 is turned off (no response). While the pushbutton switch 3 is in the ON state, the process returns to step SP5 to gradually decrease the magnitude of the vibration stimulus at a predetermined change rate (for example, 3 dB / second). On the other hand, if it is determined that the pushbutton switch 3 is turned off, in step SP7, the magnitude of the vibration stimulus at the time when the pushbutton switch 3 is turned off is set as the first descending method threshold td (1). It is stored in the control unit 11.

Next, in step SP8, it is determined whether or not the measurement by the ascending method and the measurement by the descending method are each performed three times. If it is determined that the ascending method measurement and the descending method measurement are not performed three times, in step SP9, the vibration stimulation is stopped for a predetermined stop period. On the other hand, if it is determined that the ascending method measurement and the descending method measurement have been performed three times, the process proceeds to step SP11.

In the embodiment of the present invention, the ascending method measurement and the descending method measurement are performed three times. However, in order to implement the present invention, the number of times is not limited to three. The predetermined stop period may be changed randomly (for example, 0 to 2 seconds) or may be fixed (for example, 1 second).

Next, when the vibration stimulation stop period in step SP9 has elapsed, in step SP10, the ascent method start level setting means 21 randomly changes (for example, 0 to -10 dB) with respect to the first descending method threshold value td (1). Then, the start level S2 of the second vibration stimulation is set. Next, returning to step SP2, measurement by the second ascending method is started, and the magnitude of the vibration stimulus is gradually increased from the start level S2 at a predetermined change rate (for example, 3 dB / second).

Next, when it is determined in step SP3 that the pushbutton switch 3 is turned on, in step SP4, the magnitude of the vibration stimulus at the time when the pushbutton switch 3 is turned on is the second rise method threshold ta. (2) is stored in the control unit 11.

Next, in step SP5, the magnitude of the vibration stimulus changes from increase to decrease, and the magnitude of the vibration stimulus is gradually reduced at a predetermined change rate (for example, 3 dB / second). Next, when it is determined in step SP6 that the pushbutton switch 3 is turned off, in step SP7, the magnitude of the vibration stimulus at the time when the pushbutton switch 3 is turned off is the second descending method threshold td. (2) is stored in the control unit 11.

  Next, when it is determined in step SP8 that the ascending method measurement and the descending method measurement are not performed three times, in step SP9, the vibration stimulation is stopped for a predetermined stop period. Next, when the stop period of the vibration stimulation has elapsed, in step SP10, the ascent method start level setting means 21 randomly changes (for example, 0 to −10 dB) with respect to the second descending method threshold value td (2), A start level S3 of the third vibration stimulation is set.

Next, returning to step SP2, for the third and subsequent times, measurement is performed in the same procedure as the second time, and stored in the control unit 11 as the third ascending method threshold ta (3).

Next, when it is determined in step SP8 that the ascending method measurement and the descending method measurement are each performed three times, in step SP11, a vibration sensation threshold value (VPT) is calculated. The vibration sensation threshold (VPT) is calculated by the following equation (1). Here, n is the total number of threshold pairs of the ascending method / descending method (n ≧ 3), ta (r) is the rth ascending method threshold, and td (r) is the rth descending method threshold. In the embodiment of the present invention, n = 3 and r = 3.

  Next, in step SP12, the consistency of the response of the vibration sensation threshold (VPT) calculated in step SP11 is evaluated.

Conditions for consistent display of reactions are when all of the following are met: a) The difference between the three ascending method threshold values ta (1), ta (2), and ta (3) obtained by the ascending method is 10.0 dB or the ratio is less than 3.15. b) The difference between the three descending method threshold values td (1), td (2), td (3) obtained by the descending method is 10.0 dB or the ratio is less than 3.15. c) Average value of each pair of threshold values by the ascending / descending method (ta (1) + td (1)) / 2, (ta (2) + td (2)) / 2, (ta (3) + td (3) ) / 2 is 6.0 dB or the ratio is less than 2. If the above condition is not satisfied, the inconsistency of the reaction is displayed on the liquid crystal display 18 or the like.

Then, when the consistency of the reaction with respect to the obtained vibration sensation threshold is evaluated, the measurement operation of the vibration sensation threshold ends. Further, during measurement (step SP2 to step SP12), information regarding the magnitude of the vibration stimulus may not be displayed on the screen. By not displaying on the screen, the unintentional reaction of the examiner is prevented, and the erroneous response of the subject according to the movement of the examiner is suppressed.

  According to the present invention, it changes randomly within a predetermined range with respect to the descent method threshold obtained by the descent method, and / or after the measurement by the descent method is completed and before the measurement by the ascending method is started. Since the vibration stimulus stop time is provided, the response of the subject is not at a constant interval, so that it is possible to provide a vibration sensation threshold measurement method and apparatus capable of suppressing erroneous responses and improving measurement accuracy.

DESCRIPTION OF SYMBOLS 1 ... Apparatus main body, 2 ... Exciter, 3 ... Pushbutton switch, 4 ... Load cell, 5 ... Accelerometer, 11 ... Control part, 12 ... Signal generation part, 13 ... Attenuator, 14 ... Amplifier, 15 ... A / D converter 16 ... operation switch 17 ... built-in printer 18 ... liquid crystal display 19 ... vibration stimulus level dial 21 ... rising method start level setting means 22 ... timer means 23 ... vibration sense threshold value calculating means (VPT calculation) Means), 24... Evaluation means.

Claims (8)

The ascending method for obtaining the ascending method threshold by gradually increasing the magnitude of the vibration stimulus until there is a response from the subject, and the magnitude of the vibration stimulus gradually until there is no response from the subject. In the vibration sensation threshold value measurement method obtained by repeating the descending method for obtaining the descending method threshold value by reducing the descending method threshold value, the magnitude of the vibration stimulus at the start in the ascending method is predetermined with respect to the descending method threshold value obtained by the immediately preceding descending method. A vibration sensation threshold value measuring method, characterized in that the vibration sensation threshold value setting method is performed by randomly changing the range. 2. The vibration sensation threshold value measuring method according to claim 1, wherein a vibration stimulation stop period is provided between the end of the measurement by the descending method and the start of the measurement by the ascending method. Threshold measurement method. The vibration sensation threshold value measuring method according to claim 2, wherein the stop period changes randomly within a predetermined range. The ascending method to obtain the ascending method threshold by gradually increasing the magnitude of the vibration stimulus until the subject's response, and the magnitude of the vibration stimulus until the subject's response disappears. In the vibration sensation threshold value measurement apparatus obtained by repeating the descending method for obtaining the descending method threshold by gradually decreasing the descending method threshold, the magnitude of the vibration stimulus at the start of the ascending method is equal to the descending method threshold obtained by the immediately preceding descending method. An apparatus for measuring a vibration sensation threshold value, characterized in that an ascending method start level setting means is provided which is randomly changed within a predetermined range. 5. The vibration sensation threshold value measuring apparatus according to claim 4, further comprising a timer means for setting a period for stopping the vibration stimulation between the end of the measurement by the descending method and the start of the measurement by the ascending method. A characteristic vibration sensation threshold measuring device. 6. The vibration sensation threshold value measuring apparatus according to claim 5, wherein the stop period set in the timer means changes randomly within a predetermined range. The vibration sensation threshold value measuring device according to any one of claims 4 to 6, further comprising a vibration sensation threshold value calculating unit for calculating a vibration sensation threshold value by calculating an average value of the ascending method threshold value and the descending method threshold value. A vibration sensation threshold value measuring apparatus characterized by comprising evaluation means for evaluating whether or not the vibration sensation threshold value calculated by the vibration sensation threshold value calculation means is consistent in response. 8. The vibration sensation threshold value measuring apparatus according to claim 4, wherein information regarding the magnitude of the vibration stimulus is not displayed on the screen during measurement.

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