JP2019130271A - Skin sense stimulation device and method for measuring sense threshold - Google Patents

Abstract

To provide a skin sense stimulation device and a method for measuring a sense threshold which can achieve a quantitative and highly-reproducible examination in a shorter period of time in a skin sensing examination in which temperature is used as an evaluation value.SOLUTION: A probe 10 includes a stimulation face 11a which is provided facing an examination part and which applies heat stimulation to the examination part. A heat flow sensor 11 detects a heat flux which passes through the stimulation face 11a. A temperature adjusting element 12 increases or decreases the temperature of the stimulation face 11. A reference adjusting part 23a controls the temperature adjusting element 12 such that the heat flux detected by the heat flow sensor 11 falls within a predetermined range, thereby matching the temperature of the stimulation face 11a and the temperature of the examination part. An examination performing part 23b increases or decreases the temperature of the stimulation face 11a by controlling the temperature adjusting element 12 from the state where the temperature of the stimulation face 11a matches the temperature of the examination part by the reference adjusting part 23a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a skin sensory stimulation device and a sensory threshold measurement method for stimulating warm, cold, and painful sensations by changing the temperature of a stimulation surface brought into contact with the skin.

  Conventionally, in the evaluation of pain in diseases such as chronic pain such as fibromyalgia, and the evaluation of sensory disorders associated with brain damage, spinal cord injury, diabetes, etc., skin sensation such as pain, temperature, touch, vibration, etc. Inspection is being conducted. In such inspections, realization of quantitative and more reproducible inspections is required.

  For example, Patent Document 1 discloses that in a thermal sensation testing apparatus that inspects thermal sensation by contacting a human skin surface, the skin temperature and the temperature applied to the skin can be measured with one temperature sensor, and the measured skin temperature is measured. The structure which sets the temperature which should be given in consideration of, and implements a thermal sensation test is disclosed. Further, Patent Document 2 discloses a state in which the stimulation surface of the temperature stimulation unit is arranged to face the subject's skin surface and from when the temperature stimulation by the temperature stimulation unit is started to when the subject becomes aware of warm or cold sensation. A configuration is disclosed in which a heat amount threshold value, which is a heat amount per unit area obtained based on the heat flux and temperature change with time, is used as an evaluation value of the temperature sense. Moreover, patent document 3 is disclosing the structure which judges the presence or absence of central sensitization from the residual time of the residual sensation after completion | finish of thermal stimulation when continuous thermal stimulation is applied to the test site.

  On the other hand, Non-Patent Document 1 raises the temperature from a specific temperature, and after a temperature test in which the measurement of the temperature at which the subject is aware of the temperature sensation is repeated a plurality of times, the temperature is lowered from the specific temperature, The structure which performs the cold sense test | inspection which repeats the measurement of the temperature which recognizes this several times is disclosed. Also, after increasing the temperature from a specific temperature and measuring the temperature at which the subject is aware of the temperature sensation, the temperature is decreased to measure the temperature at which the subject is aware of the cold sensation. The structure which repeats the temperature rise and temperature fall of measuring the temperature which is aware of this multiple times, and obtains the temperature at which the subject is aware of the warm or cold sense multiple times is disclosed.

JP2015-159898A Japanese Patent Laid-Open No. 10-179591 International Publication No. 2013/125518

R. Rolke et al., "Quantitative sensory testing: a comprehensive protocol for clinical trials", European Journal of Pain, 10 (2006), 77-88

  In the thermal and cold sense test, even if the subject is the same, when the skin temperature of the examination site is low (for example, 30 ° C.) or high (for example, 35 ° C.), Different. In the technology disclosed in Patent Document 1, since the configuration is set in consideration of the skin temperature obtained by measuring the temperature of the thermal stimulus applied to the examination site in the case of the thermal and cold sensation examination, it is determined regardless of the skin temperature of the examination site. Thermal sensation can be performed.

However, in the configuration disclosed in Patent Document 1, after the skin temperature is measured, the temperature of the heat-absorbing and heating element that gives thermal stimulation to the skin (for example, skin temperature + 5 ° C.) is adjusted using the same temperature sensor. During this temperature adjustment, the test probe needs to be separated from the skin of the subject so that thermal stimulation is not applied to the test site of the subject. In addition, in order to obtain a temperature difference at which the subject is aware of warm or cold sensation, it is necessary to sequentially apply thermal stimulation with different temperature differences between the skin temperature and the temperature of the heat-absorbing and heat-generating body. It is necessary to adjust the body temperature repeatedly. That is, a complicated operation of repeating the operation of bringing the inspection probe into contact with the skin and the operation of separating the probe from the skin is necessary. In addition, the skin temperature may fluctuate during the waiting time during the temperature adjustment of the heat-absorbing / heating element. In addition, when the temperature difference between the skin temperature and the temperature of the heat absorbing / generating body increases, the waiting time also increases, so the possibility that the skin temperature fluctuates further increases. The skin temperature after the fluctuation can be obtained by re-measurement. However, if the skin temperature is measured every time the temperature difference between the skin temperature and the temperature of the heat-absorbing and heating element is changed and further re-measurement is required, the inspection time will be significantly increased.

  In addition, when applying a thermal stimulus in which the temperature rises or falls continuously from the skin temperature, the skin temperature and the temperature of the heat-absorbing / heating element must be matched in advance. Such temperature adjustment needs to be performed in a state where the test site of the subject is in contact with the thermal stimulus generation site of the thermal sensation testing apparatus. At the time of this temperature adjustment, a relatively large overshoot occurs in the temperature of the heat-absorbing / heating element in the temperature adjustment based on the measurement result of the temperature sensor. Therefore, heat transfer occurs between the test site of the subject and the heat absorption / exothermic body, and the skin temperature may fluctuate during the temperature adjustment. Therefore, a problem similar to the above problem occurs.

  Further, the techniques disclosed in Patent Documents 2 and 3 propose new evaluation values, and are difficult to apply as they are to conventional skin sensation tests using temperature as an evaluation value.

  The present invention has been proposed in view of the above-described conventional circumstances, and in skin sensation inspection using temperature as an evaluation value, skin capable of realizing a quantitative and more reproducible inspection in a shorter time. An object is to provide a sensory stimulation device and a sensory threshold measurement method.

  In order to achieve the above object, the present invention employs the following technical means. First, the present invention is premised on a skin sensation stimulation apparatus that applies thermal stimulation to an examination site on the skin surface of a subject. The skin sensation stimulation device according to the present invention includes a stimulation surface, a heat flow sensor, a temperature adjustment element, a reference adjustment unit, and an examination execution unit. The stimulation surface is disposed to face the examination site and applies thermal stimulation to the examination site. The heat flow sensor detects the heat flux passing through the stimulation surface. The temperature adjustment element increases or decreases the temperature of the stimulation surface. The reference adjustment unit matches the temperature of the stimulation surface and the temperature of the examination site by controlling the temperature adjustment element so that the heat flux detected by the heat flow sensor is within a range specified in advance. The examination execution unit raises or lowers the temperature of the stimulation surface by controlling the temperature adjustment element from a state in which the temperature of the stimulation surface and the temperature of the examination site coincide with each other by the reference adjustment unit.

  In this skin sensation stimulating device, the temperature of the stimulation surface and the temperature of the examination site are made the same based on the heat flux detected by the heat flow sensor. In this configuration, the temperature of the stimulation surface and the temperature of the examination site can be matched with high accuracy in a short time. As a result, quantitative and more reproducible inspection can be realized in a shorter time.

The skin sensation stimulating apparatus further includes an input unit for inputting that the subject is aware of warm sensation, cold sensation, or pain sensation, and the inspection execution unit determines whether the temperature of the stimulation surface and the temperature of the inspection site are detected by the reference adjustment unit A configuration is adopted in which the temperature of the stimulation surface is increased or decreased by controlling the temperature adjustment element from the coincidence state, and then the temperature increase and decrease of the stimulation surface are switched each time an input is made by the subject through the input unit. be able to. In addition, each time the subject adjusts the input through the input unit, the reference adjustment unit controls the temperature adjustment element so that the heat flux detected by the heat flow sensor is within a pre-specified range. It is also possible to adopt a configuration in which the temperature of the examination site is matched. Further, the apparatus further includes a temperature acquisition unit that acquires the temperature of the stimulation surface, and the inspection execution unit is designated in advance by the reference adjustment unit with respect to the temperature of the stimulation surface in a state where the temperature of the stimulation surface matches the temperature of the inspection site. It is also possible to adopt a configuration in which the temperature of the stimulation surface is increased or decreased to the temperature obtained by adding the temperature difference.

Furthermore, the skin sensory stimulation device described above includes a temperature acquisition unit that acquires the temperature of the stimulation surface, the temperature of the stimulation surface when the subject is aware of warm sensation, cold sensation, or pain sensation, and the reference adjustment unit. The difference between the temperature of the stimulation surface when the temperature and the temperature of the examination site match, or the temperature of the stimulation surface when the subject is aware of pain sensation and the stimulation surface when the subject is aware of warm or cold sensation It is also possible to employ a configuration further including a calculation unit that calculates a difference from the temperature as a sensory threshold value. It is also possible range of predesignated heat flux described above to employ a configuration is -50 W / ^{m 2} or more and + 50 W / ^{m 2} or less.

  On the other hand, in another aspect, the present invention can also provide a method for measuring a sensory threshold when a thermal stimulus is applied to an examination site on the skin surface of a subject. That is, in the sensory threshold value measuring method according to the present invention, first, the heat flux detected by the heat flow sensor that detects the heat flux that passes through the stimulation surface that applies the thermal stimulus to the examination site is within a predetermined range. By controlling the temperature adjusting element that raises or lowers the temperature of the stimulation surface according to the state, the temperature of the stimulation surface matches the temperature of the examination site. Next, the temperature of the stimulation surface is raised or lowered by controlling the temperature adjustment element from the state where the temperature of the stimulation surface and the temperature of the examination site match. And the difference between the temperature of the stimulation surface when the subject is aware of warm sensation, cold sensation, or pain sensation, and the temperature of the stimulation surface in a state where the temperature of the stimulation surface and the temperature of the examination site match, A difference between the temperature of the stimulation surface at the time when the pain sensation is recognized and the temperature of the stimulation surface at the time when the subject is aware of the warm sensation or the cold sensation is calculated as a sensory threshold value.

  According to the skin sensory stimulation device and the sensory threshold measurement method according to the present invention, the temperature of the stimulation surface and the temperature of the examination site can be matched with high accuracy in a short time. As a result, quantitative and more reproducible inspection can be realized in a shorter time.

1 is a schematic configuration diagram showing a configuration of a skin sensation stimulation device according to an embodiment of the present invention. Schematic diagram illustrating thermal stimulation in one embodiment of the present invention The flowchart which shows an example of the measuring method of the sensory threshold in one Embodiment of this invention Schematic diagram illustrating thermal stimulation in one embodiment of the present invention The flowchart which shows an example of the measuring method of the sensory threshold in one Embodiment of this invention The figure which shows the comparative example of the measuring method of the sensory threshold in one Embodiment of this invention, and the measuring method using a temperature sensor Schematic diagram illustrating thermal stimulation in one embodiment of the present invention The flowchart which shows an example of the measuring method of the sensory threshold in one Embodiment of this invention

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a configuration of a skin sensation stimulating device according to an embodiment of the present invention. Skin sensation stimulating apparatus 100 of the present embodiment applies thermal stimulation to an inspection site (hereinafter also simply referred to as an inspection site) on the skin surface of a subject.

  In the skin sensory test using thermal stimulation, warm sensation, cold sensation, and pain sensation are evaluated. When evaluating the sense of warmth, a thermal stimulus having a temperature higher than the skin temperature is applied to the examination site, and a threshold value at which the subject is aware of the sense of warmth is acquired. When evaluating cold sensation, a thermal stimulus having a temperature lower than the skin temperature is applied to the examination site, and a threshold at which the subject is aware of cold sensation is acquired. In addition, when a subject is given a higher temperature thermal stimulus while the subject is aware of warm sensation, or when a subject is given a lower temperature thermal stimulus while being aware of cold sensation, the subject becomes aware of the pain sensation To come. At this time, pain sensation can be evaluated by acquiring a threshold value at which the subject is aware of warm sensation. The pain on the warm side is related to slow pain transmitted through the C fiber, and the pain on the cold side is related to fast pain transmitted through the Aδ fiber.

  As shown in FIG. 1, the skin sensation stimulating apparatus 100 of the present embodiment includes a probe 10 and a main body 20. First, the configuration of the probe 10 will be described. The probe 10 includes a heat flow sensor 11, a temperature adjustment element 12, and a cooling unit 13. In the present embodiment, the temperature adjustment element 12 is configured by a Peltier element. The cooling unit 13 is disposed in contact with the first surface of the Peltier element, and the heat flow sensor 11 is disposed in contact with the second surface of the Peltier element. The cooling unit 13 may be configured to absorb the heat when the first surface is in a heat generating state, and the configuration of the cooling unit 13 is not particularly limited. For example, an air-cooled heat sink or a water-cooled heat sink is used. be able to.

  As is known, the heat flow sensor 11 has a flat plate shape and detects the size of the heat flux passing through the thickness direction. In the present embodiment, in the heat flow sensor 11, the surface opposite to the contact surface of the temperature adjusting element 12 constitutes the stimulation surface 11a. Therefore, the heat flow sensor 11 detects the heat flux passing through the stimulation surface 11a. The thickness of the heat flow sensor 11 is about 0.4 mm.

  During the skin sensory test, the stimulation surface 11a is disposed in a state of facing the test site and in contact with the test site. In this state, when the second surface of the Peltier element, which is the temperature adjusting element 12, is brought into a heat generating state, the temperature of the stimulation surface 11a rises and thermal stimulation is applied to the examination site. Moreover, when the 2nd surface of a Peltier device is made into an endothermic state, the temperature of the stimulation surface 11a will fall and a cold stimulation will be provided to a test | inspection site | part.

  Although not particularly limited, the probe 10 of the present embodiment is installed on a table or the like with the stimulation surface 11a facing upward. In this state, for example, thermal stimulation is applied in a state where an examination site such as a fingertip of the subject is in contact with the stimulation surface 11a. In addition, in FIG. 1, the test subject's fingertip is shown with the broken line as the test | inspection site | part 30 as an example.

  Next, the main body 20 will be described. The main body 20 includes a heat flow acquisition unit 21, a temperature acquisition unit 22, a temperature control unit 23, an input unit 24, and a calculation unit 25. The heat flow acquisition unit 21 acquires the size of the heat flux passing through the stimulation surface based on the output value of the heat flow sensor 11. The temperature acquisition unit 22 acquires the temperature of the stimulation surface 11a. In the present embodiment, the temperature acquisition unit 22 acquires the temperature of the stimulation surface 11a by the temperature sensor 14 disposed in the center of the second surface of the Peltier element in plan view.

The temperature control unit 23 includes a reference adjustment unit 23a, an inspection execution unit 23b, and a power supply unit 23c. The reference adjustment unit 23a controls the temperature adjustment element 12 so that the magnitude of the heat flux detected by the heat flow sensor 11 falls within a range specified in advance, whereby the temperature of the stimulation surface 11a and the temperature of the examination site are determined. To match. The reference adjustment unit 23a acquires the size of the heat flux from the heat flow acquisition unit 21. In this embodiment, pre-specified range of heat flux above is -50 W / ^{m 2} or more and + 50 W / ^{m 2} or less. Outside the range, as described later, the subjective skin temperature and the subjective heat flux cannot be stably measured, which is not preferable. Although not particularly limited, in this embodiment, the direction in which heat flows from the examination site to the stimulation surface is positive.

  The reference adjusting unit 23 a adjusts the amount of heat generated or absorbed by the temperature adjusting element 12 by adjusting the energization amount of the power supply unit 23 c that supplies operating power to the temperature adjusting element 12. To match the temperature.

  The examination execution unit 23b raises or lowers the temperature of the stimulation surface 11a by controlling the temperature adjustment element 12 from a state in which the temperature of the stimulation surface 11a and the temperature of the examination site coincide with each other by the reference adjustment unit 23a. Similarly to the reference adjustment unit 23a, the inspection execution unit 23b also adjusts the amount of heat generation or heat absorption of the temperature adjustment element 12 by adjusting the energization amount of the power supply unit 23c, and increases or decreases the temperature of the stimulation surface 11a.

  The input unit 24 is used to input that the subject is aware of warm sensation, cold sensation, or pain sensation. Although not particularly limited, in the present embodiment, the input unit 24 is configured by a pushbutton switch. When the subject presses the push button to switch the switch from the off state to the on state, the fact that he / she has sensed warm sensation, cold sensation, or pain sensation is input.

  The calculation unit 25 calculates a sensory threshold value that is an evaluation value of the skin sensation. The sensory threshold includes a warm threshold, a cold threshold, and a pain threshold. The warmth threshold is a value that quantitatively indicates that the subject is aware of warmth. The cold threshold value is a value that quantitatively indicates that the subject is aware of cold sensation. The pain sensation threshold is a value that quantitatively indicates that the subject has noticed pain sensation. In the present embodiment, the calculation unit 25 matches the temperature of the stimulation surface 11a at the time when the subject is aware of warm sensation, cold sensation, or pain sensation, and the temperature of the stimulation surface 11a and the temperature of the examination site by the reference adjustment unit 23a. The difference with the temperature of the stimulation surface 11a in the performed state is calculated as a sensory threshold value. Hereinafter, the temperature of the stimulation surface 11a in a state in which the temperature of the stimulation surface 11a matches the temperature of the examination site by the reference adjustment unit 23a is appropriately referred to as a base temperature. Here, the temperature of the stimulation surface 11a is acquired. However, since the temperature of the stimulation surface 11a and the temperature of the examination site coincide with each other, the temperature of the examination site is substantially acquired.

  Next, a sensory threshold value measuring method performed by the skin sensory stimulation device 100 having the above configuration will be described. 2, 4, and 7 are schematic views illustrating thermal stimulation output from the skin sensation stimulating device 100. 2, 4, and 7, the horizontal axis corresponds to the elapsed time, and the vertical axis corresponds to the temperature. First, a case where a sensory threshold is measured under a situation where a thermal stimulus in which the temperature continuously rises as shown in FIG. 2A is applied (that is, a case where a temperature threshold is measured) will be described.

  FIG. 3 is a flowchart showing the sensory threshold measurement method. The flow proceeds as a trigger when a test start instruction is input to the main body 20 through a test start button (not shown) in a state where the test site of the subject is in contact with the stimulation surface 11a.

When the inspection start instruction is input, the reference adjusting unit 23a matches the temperature of the stimulation surface 11a with the temperature of the inspection site (No in step S301 in FIG. 3). For example, when the magnitude of the heat flux acquired by the heat flow acquisition unit 21 is a positive value, the temperature of the examination site is higher than the temperature of the stimulation surface 11a. Therefore, the reference adjustment unit 23a increases the amount of heat generated on the second surface of the Peltier element by adjusting the amount of current supplied by the power supply unit 23c to the Peltier element that is the temperature adjustment element 12. Thereby, the magnitude | size of the heat flux acquired by the heat flow acquisition part 21 becomes small gradually. In addition, when the size of the heat flux acquired by the heat flow acquisition unit 21 becomes too small due to overshoot, the reference adjustment unit 23a adjusts the energization amount to the Peltier element to generate the amount of heat generated on the second surface of the Peltier element. Increase. By repeating such control, the heat flow acquisition unit 21 matches the temperature of the stimulation surface 11a with the temperature of the examination site. As described above, in the present embodiment, the range of heat flux that is detected by the heat flow sensor 11 is designated in advance (here, -50 W / m ² or more and + 50 W / m ² or less) there become a state In other words, it is defined that the temperature of the stimulation surface 11a matches the temperature of the examination site.

When the above process is completed, the reference adjustment unit 23a notifies the inspection execution unit 23b and the calculation unit 25 that the process is completed (step S301 Yes in FIG. 3). At this time, the arithmetic unit 25 acquires the temperature of the stimulation surface 11a as a base temperature _{T 0} through temperature acquiring unit 22. In the configuration in which the energization amount to the Peltier element is adjusted according to the detection result of the heat flow sensor 11, various processes necessary for temperature adjustment based on the temperature sensor (process for converting the detected value to temperature, converted temperature and previously acquired skin) Temperature comparison and temperature determination processing is not necessary, and there is no need to wait until the temperature measurement position is in thermal equilibrium. Converge in a short time. As a result, even when compared with a configuration in which the temperature of the stimulation surface 11a is matched with the temperature of the examination site using a temperature sensor, the temperature of the stimulation surface 11a is matched with the temperature of the examination site in a short time and with high accuracy. be able to.

  The examination execution unit 23b to which the above notification is input from the reference adjustment unit 23a increases the temperature of the stimulation surface 11a (step S302 in FIG. 3). When the subject becomes aware of the temperature sensation in the process of increasing the temperature of the stimulation surface 11a, the subject notifies the main body 20 of the sense of temperature sensation through the input unit 24 (steps S303 No and S303 Yes in FIG. 3). In addition, if the temperature change rate at the time of temperature rise is large, the resolution | decomposability of temperature when a test subject will be aware of temperature sensation will fall. Therefore, it is necessary to set the rate of change in temperature when the temperature rises to a value that provides the necessary temperature resolution. Although not particularly limited, the rate of change in temperature when the temperature rises can be, for example, in the range of 0.1 to 10 degrees per second (for example, 0.3 degrees per second).

When the awareness of the warm sense is notified, the calculation unit 25 acquires the temperature of the stimulation surface 11 a through the temperature acquisition unit 22. Then, the arithmetic unit 25, and the temperature of the stimulation surface 11a at the time the subject was aware of warmth (here, Warm threshold) difference sensory threshold and base temperature T ₀ of the above is calculated as (Figure 3 step S304).

  The calculation unit 25 outputs a sensory threshold value calculated by, for example, displaying on a display unit (not shown) or transmitting data to a portable storage medium such as a USB memory through a USB (Universal Serial Bus) port (not shown). Further, when the awareness of the temperature sensation is notified, the examination execution unit 23b stops the supply of power to the temperature adjustment element 12.

  As described above, in the present embodiment, based on the heat flux detected by the heat flow sensor 11, the temperature of the stimulation surface 11a and the temperature of the examination site are matched. In this configuration, the temperature of the stimulation surface and the temperature of the examination site can be matched with high accuracy in a short time. As a result, quantitative and more reproducible inspection can be realized in a shorter time.

  Here, the relationship between the above-mentioned heat flux range specified in advance and the sensory threshold measurement result will be described. Table 1 shows the results of changing the magnitude of the heat flux detected by the heat flow sensor 11 when starting the thermal stimulation application and measuring the temperature threshold value for each. In Table 1, the setting value (heat flux condition) of the size of heat flux when starting thermal stimulation application, the skin temperature (starting skin temperature) when applying thermal stimulation, and the application of thermal stimulation are started. Actual heat flux size (starting heat flux), skin temperature when subject is aware of temperature sensation (subject skin temperature), size of heat flux when subject is aware of temperature sensation (subject heat flux) ), The time from the start of applying thermal stimulation to the time when the subject becomes aware of the temperature (awareness time), and the temperature difference between the starting skin temperature and the recognized skin temperature.

From Table 1, it can be seen that the subjective skin temperature and the subjective heat flux decrease as the starting heat flux increases (ie, as the difference between the skin temperature and the stimulation surface temperature increases). On the other hand, when the starting heat flux is 50 W / m ² or less, it can be understood that the subjective skin temperature and the subjective heat flux can be stably measured.

Note that, as described above, when a thermal stimulus at a higher temperature is applied while the subject is aware of the sense of temperature, the subject becomes aware of pain. Therefore, the test execution unit 23b obtains the pain threshold value by configuring the subject to notify the main body 20 of pain perception through the input unit 24 in the process of increasing the temperature of the stimulation surface 11a. Is possible. In this case, the arithmetic unit 25 subjects the temperature of the stimulation surface 11a at the time of conscious of pain, the difference sensation threshold of (in this case, the pain threshold) and base temperature T ₀ of the above is calculated as.

Furthermore, sensory threshold, such as described above, the calculated relative to the base temperature T ₀ of the above, it is possible to obtain a more stable value. Tables 2 and 3 show the results of measurement of the sensation threshold and the pain threshold. Here, thermal stimulation in which the temperature rises continuously is given to four subjects without sensory impairment. In Table 2, when the application of thermal stimulation is started, the temperature of the stimulation surface 11a is matched with the temperature of the examination site. In Table 3, when the application of thermal stimulation is started, the temperature of the stimulation surface 11a is set to a specific temperature (here, 30 ° C.). In Table 2, the temperature of the test site (starting skin temperature) when applying thermal stimulation, the temperature of the stimulation surface 11a when detecting thermal sensation in the process of applying thermal stimulation (temperature consciousness temperature), and thermal stimulation 3 shows the temperature of the stimulation surface 11a (pain perception temperature), the difference between the temperature perception temperature and the start skin temperature, and the difference between the perception perception temperature and the start skin temperature, respectively. Similarly, in Table 3, the temperature (starting temperature) of the stimulation surface 11a at the start of applying the thermal stimulus, and the temperature of the stimulation surface 11a when the thermal sense is sensed in the process of applying the thermal stimulus (temperature consciousness temperature). , The temperature of the stimulation surface 11a (pain perception temperature), the difference between the perception temperature and the start temperature, and the difference between the perception temperature and the start temperature, respectively, when the pain sensation is recognized in the process of applying thermal stimulation. .

  From Table 2 and Table 3, it can be understood that the measured value of the temperature perception temperature and the measurement value of the pain perception temperature have the same degree of variation in any case. On the other hand, it can be understood that the difference between the temperature perception temperature and the starting skin temperature in Table 2 is smaller in the variation of values for each subject than the difference between the temperature perception temperature and the starting temperature in Table 3. . Similarly, it can be understood that the difference between the perceived pain temperature and the starting skin temperature in Table 2 is smaller than the difference between the perceived pain temperature and the starting temperature in Table 3 for each subject.

As a result, by calculating the Warm threshold and pain threshold relative to the base temperature T ₀ of the above show that it is possible to obtain a stable value with less variation among subjects. From another viewpoint, the fact that the variation in the warmth threshold and the pain threshold is small means that each subject is aware of the applied thermal stimulus as a similar stimulus. Therefore, compared to setting a temperature difference based on a specific temperature as a thermal stimulus, a subject with no sensory impairment has a similar temperature when setting a temperature difference based on the starting skin temperature as a thermal stimulus. It can be said that a stimulus that is felt as a sensation stimulus or a pain sensation can be applied more stably.

In the above description, the configuration is described in which the temperature of the examination site is matched with the temperature of the stimulation surface 11a, and then the thermal stimulation is applied in which the temperature continuously rises from the temperature of the examination site. It is also possible to apply a thermal stimulus in which the temperature continuously decreases from the temperature of the examination site as shown in FIG. In this configuration, the test execution unit 23b notifies the main body 20 that the subject has sensed cold through the input unit 24 in the process of lowering the temperature of the stimulation surface 11a, whereby the cold threshold is set. It becomes possible to get. In this case, the arithmetic unit 25 calculates the temperature of the stimulation surface 11a at the time the subject was aware of the cold sensation, the difference between the base temperature T ₀ of the above as a cold sensation threshold. Similarly, the test execution unit 23b obtains a pain threshold by notifying the main body 20 that the subject has noticed pain through the input unit 24 in the process of lowering the temperature of the stimulation surface 11a. It becomes possible. In this case, the calculation unit 25 calculates the difference between the above-described base temperature T ₀ and the temperature of the stimulation surface 11a at the time when the subject senses pain as a pain threshold. In the above description, the temperature change rate per unit time of thermal stimulation in which the temperature continuously rises or falls is constant, but the temperature change rate per unit time increases with the elapsed time or unit time A thermal stimulus in which the rate of change in temperature per hour decreases with time may be used.

In addition, the examination execution unit 23b does not perform thermal stimulation in which the temperature continuously rises or falls as shown in FIGS. 2A and 2B, but FIGS. 2C and 2D. The structure which gives the thermal stimulus which temperature rises or falls in steps as shown in FIG. For example, the thermal stimulation in which the temperature rises stepwise calculates, for example, a plurality of set temperatures obtained by sequentially adding a predetermined temperature difference with respect to the base temperature T ₀ , and the temperature of the stimulation surface 11 a is determined for a predetermined time. This can be achieved by maintaining the calculated temperatures at intervals. Similarly, for the thermal stimulation in which the temperature falls stepwise, for example, a plurality of set temperatures obtained by sequentially subtracting a temperature difference designated in advance from the base temperature T ₀ are calculated, and the temperature of the stimulation surface 11a is calculated for a time designated in advance. This can be achieved by maintaining each calculated temperature at each temperature. 2C and 2D show examples in which the temperature difference sequentially added or subtracted with respect to the base temperature T ₀ is the same, but the temperature difference sequentially added or subtracted is different. May be. Further, a configuration in which addition and subtraction are mixed (that is, a configuration in which a temperature increase and a temperature decrease are mixed) may be employed. Similarly, FIGS. 2C and 2D show examples in which the time for maintaining the temperature of the stimulation surface 11a at the calculated temperatures is the same, but the time for maintaining the temperature is different. May be. A configuration in which the calculation unit 25 performs the calculation of the set temperature as described above may be employed.

In this way, by setting the thermal stimulus as a temperature difference with reference to the base temperature T ₀ , the stimulus that the subject feels to the same degree is more stably applied to the test site of each subject as described above. It becomes possible.

  Next, as shown in FIG. 4, a sensory threshold is measured in a situation where a thermal stimulus with a continuously rising temperature and a thermal stimulus with a continuously decreasing temperature are repeatedly applied (that is, a warm threshold and a cold threshold). A case in which the sensation threshold value is measured alternately and continuously will be described.

  FIG. 5 is a flowchart showing the sensory threshold measurement method. The flow proceeds as a trigger when a test start instruction is input to the main body 20 through a test start button (not shown) in a state where the test site of the subject is in contact with the stimulation surface 11a.

When the examination start instruction is input, the reference adjusting unit 23a matches the temperature of the stimulation surface 11a with the temperature of the examination site by the above-described method (No in step S501 in FIG. 5). When the process is completed, the reference adjustment unit 23a notifies the inspection execution unit 23b and the calculation unit 25 (Yes in step S501). At this time, the arithmetic unit 25 acquires the temperature of the stimulation surface 11a as a base temperature _{T 0} through temperature acquiring unit 22.

  The examination execution unit 23b to which the above notification is input from the reference adjustment unit 23a increases the temperature of the stimulation surface 11a (step S502 in FIG. 5). When the subject becomes aware of the temperature sensation in the process of increasing the temperature of the stimulation surface 11a, the subject notifies the main body 20 of the sense of temperature sensation through the input unit 24 (No in steps S503 and S503 in FIG. 5).

When the awareness of the warm sense is notified, the calculation unit 25 acquires the temperature of the stimulation surface 11 a through the temperature acquisition unit 22. Then, the arithmetic unit 25 calculates the difference between the base temperatures T ₀ temperature above the stimulation surface 11a at the time the subject was aware of Warm as Warm threshold (Fig. 5 step S504).

  In addition, when the awareness of the warm sense is notified, the examination performing unit 23b switches the temperature of the stimulation surface 11a from the temperature increase to the temperature decrease (No in steps S505 and S506 in FIG. 5). When the subject is aware of cold sensation in the process of the temperature of the stimulation surface 11a decreasing, the subject notifies the main body 20 of the sense of cold through the input unit 24 (steps S503 No and S503 Yes in FIG. 5).

When notified of the cold sensation, the calculation unit 25 acquires the temperature of the stimulation surface 11 a through the temperature acquisition unit 22. Then, the arithmetic unit 25 calculates the difference between the temperature of the stimulation surface 11a at which the base temperature T ₀ and the subject described above is aware of cold sensation as cold sensation threshold (Fig. 5 step S504).

  In addition, when notified of the cold sensation, the examination performing unit 23b switches the temperature of the stimulation surface 11a from a temperature decrease to a temperature increase (No in steps S505 and S506 in FIG. 5). When the subject becomes aware of the temperature sensation in the process of increasing the temperature of the stimulation surface 11a, the subject notifies the main body 20 of the sense of temperature sensation through the input unit 24 (No in steps S503 and S503 in FIG. 5).

  When the awareness of the warm sense is notified, the calculation unit 25 acquires the temperature of the stimulation surface 11a through the temperature acquisition unit 22, and calculates the temperature threshold as described above (step S504 in FIG. 5).

  The examination execution unit 23b performs the switching between the continuous temperature increase thermal stimulation and the continuous temperature decrease thermal stimulation as described above a predetermined number of times. When the number of times of switching reaches the number of times designated in advance, the inspection execution unit 23b stops supplying power to the temperature adjustment element 12 (steps S505 and S506 in FIG. 5).

  As described above, in this case, the examination execution unit 23b controls the temperature adjustment element 12 from the state in which the temperature of the stimulation surface 11a and the temperature of the examination site coincide with each other by the reference adjustment unit 23a. After raising or lowering, each time an input is made by the subject through the input unit 24, the temperature of the stimulation surface 11a is switched between increasing and decreasing. By such a series of thermal stimulations, it is possible to acquire a sensory threshold value in a state where the examination site is used to the thermal stimulation.

  In this type of examination, if there is a temperature difference between the temperature of the examination site and the temperature of the stimulation surface 11a at the start of applying thermal stimulation, the measured warm threshold and cold threshold tend to vary widely (warm temperature). The difference between the average value of the sensation threshold and the average value of the cold sensation threshold tends to increase). When the variation is large, the quantitative property is lowered, and the difference between the warm threshold and the cold threshold is increased, resulting in a longer examination time.

  FIG. 6 is a diagram illustrating a comparative example of the sensory threshold measurement method and the measurement method using the temperature sensor in the present embodiment. In FIG. 6, the horizontal axis corresponds to the elapsed time, and the vertical axis corresponds to the temperature. The sensory threshold measurement method in the present embodiment is indicated by a solid line, and the measurement method using a temperature sensor is indicated by a broken line and a one-dot chain line. In the example of FIG. 6, the measurement of the warm threshold and the measurement of the cold threshold are repeated five times. Here, in order to explain the influence of the temperature difference on the temperature of the examination site and the temperature of the stimulation surface 11a at the time when the application of thermal stimulation is started, in the measurement method using the temperature sensor, the temperature difference is increased. ing. Further, it can be understood that the variation of the sensory threshold perceived by the subject is larger than the sensory threshold measurement method in the present embodiment, and the examination time is longer than the sensory threshold measurement method in the present embodiment. That is, the sensory threshold value measurement method in the present embodiment has a shorter time for matching the temperature of the examination site and the temperature of the stimulation surface 11a than the measurement method using the temperature sensor, and the examination time itself. In addition, it can be said that stable measurement with little variation is possible.

  Subsequently, as shown in FIG. 7, the sensory threshold value is set in a situation where the thermal stimulation is continuously applied with the temperature rising a plurality of times, and then the thermal stimulation is continuously applied with the temperature decreasing a plurality of times. A case where measurement is performed (that is, a case where the cold threshold is continuously measured a plurality of times after the temperature threshold is continuously measured a plurality of times) will be described.

  FIG. 8 is a flowchart showing the sensory threshold measurement method. The flow proceeds as a trigger when a test start instruction is input to the main body 20 through a test start button (not shown) in a state where the test site of the subject is in contact with the stimulation surface 11a.

When the examination start instruction is input, the reference adjusting unit 23a matches the temperature of the stimulation surface 11a with the temperature of the examination site by the above-described method (No in step S801 in FIG. 8). When the processing is completed, the reference adjustment unit 23a notifies the inspection execution unit 23b and the calculation unit 25 (Yes in step S801 in FIG. 8). At this time, the arithmetic unit 25 acquires the temperature of the stimulation surface 11a as a base temperature _{T 0} through temperature acquiring unit 22.

The examination execution unit 23b to which the above notification is input from the reference adjustment unit 23a increases the temperature of the stimulation surface 11a (step S802 in FIG. 8). When the subject becomes aware of the temperature sensation in the process of increasing the temperature of the stimulation surface 11a, the subject notifies the main body 20 of the sense of temperature sensation through the input unit 24 (No in steps S803 and S803 in FIG. 8).

When the awareness of the warm sense is notified, the calculation unit 25 acquires the temperature of the stimulation surface 11 a through the temperature acquisition unit 22. Then, the arithmetic unit 25 calculates the difference between the temperature of the stimulation surface 11a at the time the subject was aware of the warmth and base temperature T ₀ of the above as Warm threshold (FIG. 8 step S804).

In addition, when the awareness of the warm sense is notified, the examination execution unit 23b instructs the reference adjustment unit 23a to match the temperature of the stimulation surface 11a with the temperature of the examination site. Receiving the instruction, the reference adjusting unit 23a matches the temperature of the stimulation surface 11a with the temperature of the examination site by the above-described method (steps S805 No and S801 No in FIG. 8). When the processing is completed, the reference adjustment unit 23a notifies the inspection execution unit 23b and the calculation unit 25 (Yes in step S801 in FIG. 8). At this time, the arithmetic unit 25 acquires the temperature of the stimulation surface 11a as a new base temperature T ₀ through temperature acquiring unit 22.

  The examination execution unit 23b to which the above notification is input from the reference adjustment unit 23a increases the temperature of the stimulation surface 11a (step S802 in FIG. 8). In this process, when the subject becomes aware of the temperature sensation, the subject notifies the main body 20 of the sense of temperature sensation through the input unit 24 (No in steps S803 and S803 in FIG. 8).

When the awareness of the warm sense is notified, the calculation unit 25 acquires the temperature of the stimulation surface 11 a through the temperature acquisition unit 22. Then, the arithmetic unit 25 calculates the difference between subjects and temperature stimuli surface 11a at the time of conscious of warmth as a new base temperature T ₀ of the above as Warm threshold (FIG. 8 step S804).

  The examination execution unit 23b performs the temperature threshold measurement as described above for the number of times designated in advance. When the number of times specified in advance is reached, the examination execution unit 23b performs the number of times specified in advance to measure the cold sensation threshold by the same method using the heat stimulation in which the temperature continuously decreases from the base temperature. Just implement. When the number of times designated in advance is reached, the power supply to the temperature adjustment element 12 is stopped (step S805 Yes in FIG. 8).

  As described above, in this case, the reference adjustment unit 23a is configured so that the heat flux detected by the heat flow sensor 11 is within a predesignated range each time input by the subject is made through the input unit 24. 12 is made to match the temperature of the stimulation surface 11a with the temperature of the examination site. By such a series of thermal stimulation, it is possible to perform a test in which the warm threshold and the cold threshold are measured a plurality of times in a short time.

  As described above, in the skin sensation stimulating device 100, based on the heat flux detected by the heat flow sensor 11, the temperature of the stimulation surface 11a and the temperature of the examination site are made the same. In this configuration, the temperature of the stimulation surface 11a and the temperature of the examination site can be matched with high accuracy in a short time. As a result, quantitative and more reproducible inspection can be realized in a shorter time.

The above-described embodiments do not limit the technical scope of the present invention, and various modifications and applications other than those already described are possible within the scope of the present invention. For example, in the above embodiment, the calculation unit 25 exemplifies a configuration in which the pain threshold is calculated based on the difference between the temperature of the stimulation surface when the subject is aware of pain and the base temperature T ₀ , but the subject is aware of pain. The difference between the temperature of the stimulation surface at the time of the stimulation and the temperature of the stimulation surface when the subject is aware of the warm or cold sensation may be calculated as the pain threshold. That is, under the situation where a thermal stimulus that continuously increases in temperature as shown in FIG. 2A is applied, even after the subject has notified the main body 20 of the sense of temperature through the input unit 24. The temperature rise is continued, and the subject notifies the main body 20 of the pain perception through the input unit 24. And the calculating part 25 calculates the difference of the temperature of the stimulation surface 11a when a test subject is aware of pain sensation, and the temperature of the stimulation surface 11a when a test subject is aware of warm sense as a pain threshold value. According to such a configuration, it is possible to quantitatively evaluate the magnitude of a stimulus that feels pain with respect to slow pain transmitted through the C fiber with reference to a sensible stimulus.

  Similarly, after applying a thermal stimulus to the main body 20 through the input unit 24 in a situation in which a thermal stimulus in which the temperature continuously decreases as shown in FIG. In addition, the temperature continues to decrease, and the subject notifies the main body 20 of the pain through the input unit 24. And the calculating part 25 calculates the difference of the temperature of the stimulation surface 11a when a test subject is aware of pain sensation, and the temperature of the stimulation surface 11a when a test subject is aware of cold sensation as a pain threshold value. According to such a configuration, with respect to fast pain transmitted through the Aδ fiber, the magnitude of the stimulus that feels pain can be quantitatively evaluated with reference to a stimulus that can be perceived.

Moreover, in the said embodiment, although it was set as the structure provided with the calculating part 25 as a particularly preferable form, providing the calculating part 25 is not essential. For example, it may be configured to output only the temperature of the stimulation surface 11a when the subject is aware of warm sensation, cold sensation, or pain sensation, and may be configured to separately perform a calculation for calculating a sensory threshold. Furthermore, it is not essential to provide the input unit 24. In this case, for example, a display unit that displays the temperature of the stimulation surface 11a is provided on the main body 20, and when the subject is aware of warm sensation, cold sensation, or pain sensation, the temperature displayed on the display unit is determined by the tester ( It is possible to adopt a configuration in which an operator) records. In addition, when a specific temperature or a temperature having a specific temperature difference from the base temperature T ₀ is displayed on the display unit, the test subject verbally answers the degree of warm sensation, cold sensation, or pain sensation You can also

  Further, in the flowcharts shown in FIGS. 3, 5, and 8, the order of the steps can be appropriately changed within a range where the equivalent operation is achieved. For example, in the flowcharts shown in FIGS. 5 and 8, the sensory threshold value is calculated every time there is an input by the subject through the input unit. However, the calculation for calculating the sensory threshold value is performed collectively at an arbitrary timing. Also good.

  Furthermore, the thermal stimulation profiles shown in FIGS. 4 and 7 are merely examples, and for example, the respective profiles illustrated in FIG. 2 can be used as the thermal stimulation profiles of each time shown in FIGS. is there.

  ADVANTAGE OF THE INVENTION According to this invention, a quantitative and more reproducible test | inspection can be implement | achieved in a short time, and it is useful as a skin sensory stimulation apparatus and the measuring method of a sensory threshold value.

DESCRIPTION OF SYMBOLS 10 Probe 11 Heat flow sensor 11a Stimulation surface 12 Temperature adjustment element 21 Heat flow acquisition part 22 Temperature acquisition part 23 Temperature control part 23a Reference adjustment part 23b Inspection execution part 23c Power supply part 24 Input part 25 Calculation part 30 Inspection part

Claims (7)

A skin sensation stimulating device that applies thermal stimulation to an examination site on the skin surface of a subject,
A stimulation surface that is disposed opposite to the examination site and that applies the thermal stimulation to the examination site;
A heat flow sensor for detecting a heat flux passing through the stimulation surface;
A temperature adjusting element for increasing or decreasing the temperature of the stimulation surface;
A reference adjustment unit that matches the temperature of the stimulation surface and the temperature of the examination site by controlling the temperature adjustment element so that the heat flux detected by the heat flow sensor falls within a predetermined range; and
An examination execution unit that raises or lowers the temperature of the stimulation surface by controlling the temperature adjustment element from a state in which the temperature of the stimulation surface and the temperature of the examination site coincide with each other by the reference adjustment unit;
A skin sensation stimulator comprising: Further comprising an input unit for inputting that the subject is aware of warm sensation, cold sensation, or pain sensation,
The examination execution unit increases or decreases the temperature of the stimulation surface by controlling the temperature adjustment element from a state in which the temperature of the stimulation surface and the temperature of the examination site coincide with each other by the reference adjustment unit, The skin sensation stimulation device according to claim 1, wherein each time an input is made by the subject through the input unit, a temperature increase and a temperature decrease of the stimulation surface are switched. Further comprising an input unit for inputting that the subject is aware of warm sensation, cold sensation, or pain sensation,
The reference adjustment unit controls the temperature adjustment element so that the heat flux detected by the heat flow sensor is within a predetermined range each time an input is made by the subject through the input unit. The skin sensation stimulating apparatus according to claim 1, wherein the temperature of the stimulation surface is matched with the temperature of the examination site. A temperature acquisition unit for acquiring the temperature of the stimulation surface;
The temperature of the stimulation surface when the temperature of the stimulation surface coincides with the temperature of the stimulation surface when the subject is aware of warm sensation, cold sensation, or pain sensation, and the reference adjustment unit. Or the difference between the temperature of the stimulation surface when the subject is aware of pain and the temperature of the stimulation surface when the subject is aware of warm or cold as a sensory threshold When,
The skin sensation stimulator according to any one of claims 1 to 3, further comprising: A temperature acquisition unit for acquiring the temperature of the stimulation surface;
The examination execution unit adds the temperature difference specified in advance to the temperature of the stimulation surface in a state where the temperature of the stimulation surface matches the temperature of the examination site by the reference adjustment unit. The skin sensation stimulating device according to claim 1, wherein the temperature of the skin is raised or lowered. The pre-specified range of heat flux is -50 W / m ² or more and + 50 W / m ² or less, cutaneous sense stimulation device according to any one of claims 1 to 5. A method for measuring a sensory threshold when a thermal stimulus is applied to an examination site on a skin surface of a subject,
A temperature that raises or lowers the temperature of the stimulation surface so that the heat flux detected by the heat flow sensor that detects the heat flux passing through the stimulation surface that gives the thermal stimulation to the examination site is within a predetermined range. Adjusting the temperature of the stimulation surface and the temperature of the examination site by controlling an adjustment element;
Increasing or decreasing the temperature of the stimulation surface by controlling the temperature adjustment element from a state in which the temperature of the stimulation surface and the temperature of the examination site coincide with each other;
The difference between the temperature of the stimulation surface when the subject is aware of warm, cold, or pain sensation, and the temperature of the stimulation surface in a state where the temperature of the stimulation surface matches the temperature of the examination site, or Calculating the difference between the temperature of the stimulation surface when the subject is aware of pain and the temperature of the stimulation surface when the subject is aware of warm or cold as a sensory threshold;
A method for measuring a sensory threshold value.

Images