DEVICE

[Technical Field]

The present invention relates, in general, to a method of controlling the temperature of a cold/warm forehead massage device and, more particularly, to a method of controlling the temperature of a cold/warm forehead massage device, which controls the temperature of the cold/warm forehead massage device using low input power, thus enabling the skin to feel a cold sensation more efficiently.

[Background Art]

An example of a patent related to a conventional apparatus for stimulating the skin using cold and heat is an

"Apparatus for locally cooling the skin using a thermoelectric semiconductor device", disclosed in Korean Pat. Appln. No.

1995-0020963, filed and registered.

As shown in FIG. 1, the above patent discloses an apparatus for locally cooling the skin that includes a heat absorption means having a thermoelectric module 2, a control means for performing a control operation to allow the heat absorption means to repeat a cooling cycle, and an attachment means for attaching the heat absorption means to a human body. However, the above patent is problematic in that it merely turns on or off power to cool the skin, but cannot control the temperature in consideration of the physiological

characteristics of a human body.

[Disclosure of the Invention]

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a method of controlling the temperature of a cold/warm forehead massage device, which applies different currents to a thermoelectric element at different periods, thereby transferring cold/warm stimulation to the skin in consideration of the physiological characteristics of a human body, and minimizing power applied to the massage device.

In order to accomplish the above object, the present invention provides a method of controlling temperature of a cold/warm forehead massage device, the cold/warm forehead massage device including a casing and a thermoelectric element assembly, the thermoelectric element assembly including a power supply unit, a control unit, a thermoelectric element, a cold/warm heat plate, a temperature sensing unit and a temperature adjustment unit, the method comprising the steps of (a) the control unit supplying first current required to generate cold stimulation to the thermoelectric element; (b) the control unit measuring time for which the first current is supplied, and determining whether the measured time has exceeded a first time,- (c) if it is determined that the measured time has not exceed the first time at step (b) , the control unit retuning to step (a) , whereas if it is determined that the measured time has exceeded the first time, the control

unit supplying second current required to generate warm stimulation to the thermoelectric element; (d) the control unit measuring time for which the second current is supplied, and determining whether the measured time has exceeded a second time; (e) if it is determined that the measured time has not exceeded the second time at step (d) , the control unit returning to step (c) , whereas if it is determined that the measured time has exceeded the second time at step (d) , the control unit supplying third current required to generate cold stimulation to the thermoelectric element; and (f) the control unit measuring time for which the third current is supplied, determining whether the measured time has exceeded a third time, returning to step (e) if it is determined that the measured time has not exceeded the third time, but terminating temperature control if it is determined that the measured time has exceeded the third time.

[Brief Description of the Drawings]

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a sectional view of a conventional apparatus for locally cooling the skin,-

FIG. 2A illustrates an actual picture of the front side of a cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 2B illustrates an actual picture of the rear side

of the cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 3 is a block diagram of a thermoelectric element assembly according to an embodiment of the present invention; FIG. 4 is a flowchart of a method of controlling the temperature of the cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 5 illustrates an actual picture showing the temperature of the cold/warm forehead massage device measured by a thermometer according to an embodiment of the present invention;

FIG. 6 illustrates an actual picture showing the temperature of the cold/warm forehead massage device measured by the thermistor pod of an AD instrument according to an embodiment of the present invention;

FIG. 7A is a view showing a protocol for the evaluation of subjective perception of first cold stimulation using the cold/warm forehead massage device according to an embodiment of the present invention; FIG. 7B is a view showing a protocol for the evaluation of subjective perception of second cold stimulation using the cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 7C is a view showing a protocol for the evaluation of subjective perception of third cold stimulation using the cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 8A is a view showing a first step protocol for a four-time cold stimulation experiment done using the cold/warm

forehead massage device according to an embodiment of the present invention;

FIG. 8B is a view showing a second step protocol for a four-time cold stimulation experiment done using the cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 8C is a view showing a third step protocol for a two-time cold stimulation experiment done using the cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 9 illustrates an actual picture showing a primary- experiment done using the cold/warm forehead massage device according to an embodiment of the present invention;

FIG. 1OA is a graph showing the external temperature of the cold/warm forehead massage device measured by a thermometer for 6 minutes according to an embodiment of the present invention;

FIG. 1OB is a graph showing the external temperature of the cold/warm forehead massage device measured by a thermometer for 10 minutes according to an embodiment of the present invention;

FIG. 11A is a graph showing the external temperature of the cold/warm forehead massage device measured by a thermistor for 25 minutes according to an embodiment of the present invention;

FIG. HB is a graph showing the external temperature of the cold/warm forehead massage device measured by a thermistor for 2 hours according to an embodiment of the present invention;

FIG. 12A is a graph showing a temperature curve obtained from the evaluation of subjective perception of first cold stimulation according to an embodiment of the present invention; FIG. 12B is a graph showing a temperature curve obtained from the evaluation of subjective perception of second cold stimulation according to an embodiment of the present invention;

FIG. 12C is a graph showing a temperature curve obtained from the evaluation of subjective perception of third cold stimulation according to an embodiment of the present invention;

FIG. 13A is a graph showing the aspects of variation in LF and HF of HRV before and after the application of stimulation according to an embodiment of the present invention;

FIG. 13B is a graph showing the aspects of variation in the ratio of LF/HF of HRV before and after the application of cold stimulation in first and second step experiments according to an embodiment of the present invention;

FIG. 13C is a graph showing the analysis of HLV in a primary experiment according to an embodiment of the present invention;

FIG. 14 is a graph showing the analysis of HRV in an experiment for the reproducibility of the primary experiment according to an embodiment of the present invention;

FIG. 15 is a graph showing the analysis of HRV in cold and heat syndromes according to an embodiment of the present invention;

FIG. 16 is a graph showing the comparison between cold and heat syndromes for cold stimulation according to an embodiment of the present invention;

FIG. 17 is a graph showing the analysis of HRV in a warm stimulation experiment for cold syndrome according to an embodiment of the present invention; and

FIG. 18 is a view showing an optimal protocol for a cold stimulation experiment according to an embodiment of the present invention.

[Best Mode for Carrying Out the Invention]

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings .

The structure of a cold/warm forehead massage device according to an embodiment of the present invention is described with reference to FIGS . 2A and 2B and FIG. 3.

FIG. 2A illustrates an actual picture of the front side of a cold/warm forehead massage device according to an embodiment of the present invention, FIG. 2B illustrates an actual picture of the rear side of the cold/warm forehead massage device according to an embodiment of the present invention, and FIG. 3 is a block diagram of a thermoelectric element assembly according to an embodiment of the present invention.

As shown in FIGS. 2A and 2B, the forehead massage device according to the present invention includes a casing 100 and a thermoelectric element assembly 200 separated into a plurality of parts .

The casing 100 is made of material having light weight such as aluminum, and is formed in a semicircular shape that is curved overall .

Further, the thermoelectric element assembly 200, separated into a plurality of parts, can move depending on the size of the head of a user after being fixed in the casing 100, thus performing a cold/warm fomentation function, with the massage device worn on the forehead of the user. As shown in

FIG. 3, the thermoelectric element assembly 200 includes a power supply unit 210, a control unit 220, a thermoelectric element 230, a cold/warm heat plate 240, a temperature sensing unit 250 and a temperature adjustment unit 260.

The power supply unit 210 functions to receive Alternating Current (AC) current, convert the AC current into Direct Current (DC) current, and supply the DC current.

The control unit 220 compares temperature, which is set by the temperature adjustment unit 260 by adjusting the intensity and direction of current supplied to the thermoelectric element 230, with the temperature of the cold/warm heat plate 240 sensed by the temperature sensing unit

250, and controls the current supplied by the power supply unit

210 to the thermoelectric element 230 in conformity with the difference between the temperatures, thus determining the amount of heat to be absorbed or generated by the thermoelectric element 230.

The thermoelectric element 230 is disposed to be adjacent to the cold/warm heat plate 240 and simultaneously performs the functions of generating and absorbing heat using the current supplied by the power supply unit 210.

The cold/warm heat plate 240 is adjacent to the thermoelectric element 230, and functions to be provided with cool air and warm air by the thermoelectric element 230 and to provide the cool air and the warm air to the skin of a user. The temperature sensing unit 250 functions to sense the temperature of the thermoelectric element 230 by being connected to the thermoelectric element 230, and to transmit information about the sensed temperature to the control unit 220. The temperature adjustment unit 260 functions to set the temperature of the thermoelectric element 230 to temperature desired by the user while being connected to the control unit 220.

A method of controlling the temperature of the cold/warm forehead massage device according to an embodiment of the present invention having the above construction is described with reference to FIG. 4.

FIG. 4 is a flowchart of a method of controlling the temperature of the cold/warm forehead massage device according to an embodiment of the present invention.

The control unit 220 supplies first current to the thermoelectric element 230 at step S2.

In this embodiment, the first current supplied to the thermoelectric element 230 is set to current required for causing the temperature of the thermoelectric element 230 to be

5°C to 15°C, but the present invention is not limited to the embodiment .

The control unit 220 measures the time for which the first current is supplied, and determines whether the measured

time has exceeded a first time at step S4.

In this embodiment, the first time is set to 3 minutes, but the present invention is not limited to the embodiment .

As a result of the determination at step S4, if the measured time has not exceed the first time, the control unit 220 returns to step S2, whereas if the measured time has exceeded the first time, the control unit 220 supplies second current, having polarity opposite to that of the first current, to the thermoelectric element 230 at step S6. In this embodiment, the second current is set to current required for causing the temperature of the thermoelectric element 230 to be 20°C to 35°C, but the present invention is not limited to the embodiment.

The control unit 220 measures the time for which the second current is supplied, and determines whether the measured time has exceeded a second time at step S8.

In this embodiment, the second time is set to one minute, but the present invention is not limited to the embodiment . As a result of the determination at step S8, if the measured time has not exceeded the second time, the control unit 220 returns to step S6, whereas if the measured time has exceeded the second time, the control unit 220 supplies third current to the thermoelectric element 230 at step SlO. In this embodiment, the third current supplied to the thermoelectric element 230 is set to current required for causing the temperature of the thermoelectric element 230 to be

5°C to 15°C, but the present invention is not limited to the embodiment .

The control unit 220 measures the time for which the third current is supplied, and determines whether the measured time has exceeded a third time at step S12. If the measured time has not exceed the third time at step S12, the control unit 220 returns to step SlO, whereas if the measured time has exceeded the third time, the control unit 220 terminates the process of controlling the temperature of the cold/warm forehead massage device according to the embodiment of the present invention. In this embodiment, the first and third currents are set to the same value, and the second current is set to have polarity opposite to that of the first current, so that the polarities of the currents supplied at respective times during a single operating period can be set to be continuously switched. In this embodiment, the first and third times are set to the same time, and the second time is set to be shorter than the first time, but the present invention is not limited to the embodiment .

An actual experimental process using optimal stimulation protocols (cold stimulation time, stimulation intensity, etc.) in the cold/warm forehead massage device according to the embodiment of the present invention is described in detail with reference to FIGS . 5 to 18.

1. Outline of experimental method

1.1 Experimental subject selection

Experimental subjects were male university students, and the number thereof was 15, but the number of experimental subjects was adjusted in a plurality of experimental protocols.

Whether each experimental subject had ever used a similar product made by another company was determined, and the sensitivity of each experimental subject to machines was considered through preliminary questions. Then, if a corresponding experimental subject had a history of disease

(epilepsy or fits) , the subject was excluded from the group of experimental subjects. Further, since the status control of each experimental subject is required first of all, information about experiments was not provided to the experimental subjects.

1.2 Progress of experimental research

This research was conducted according to the following 4-step procedure. (1) Evaluation of cold stimulation device

(2) Evaluation of subjective perception of cold stimulation

(3) Primary experiment

(4) Secondary experiment First, the evaluation of the temperature characteristics of a cold/warm forehead massage device according to the embodiment of the present invention used in the experiments (hereinafter referred to as a "cold stimulation device") was conducted. Second, the evaluation of the subjective perception of an experimental subject to the temperature variation of the device was conducted. Further, based on the above evaluation, the protocol for cold stimulation experiments that was predicted to be most suitable and effective was established. Third, a primary experiment was conducted, in which aspects of

physiological variation in the human body were examined while various cold stimulations were applied to the human body. Using the protocol considered to be most suitable, experiments were conducted on 15 cases corresponding to experimental subjects. Finally, after the results of the primary experiment had been analyzed, a secondary experiment was planned. The object of the secondary experiment is to carry out comparison experiments using light + auditory stimulation, and light + auditory + cold stimulation, classify experimental subjects into groups of people exhibiting cold and heat syndromes, and determine the differences between the groups . Hereinafter, the progress of experimental research at respective steps is described below.

1.2.1 Evaluation of cold stimulation device

Prior to the present experimental research, the evaluation of the characteristics of the cold stimulation device was required. First, temperature variation, obtained when the cold stimulation device was operating, was investigated, and thereafter temperature variation, obtained when the cold stimulation device was attached to skin, was examined. Further, aspects of the temperature variation of the device, obtained during the operation of the device, were additionally examined. The evaluation of the temperature of the cold stimulation device was conducted through primary and secondary experiments using a thermometer and the thermistor pod electrode of an AD instrument, as shown in FIGS. 5 and 6.

1.2.2 Evaluation of subjective perception of cold

stimulation

Aspects of the temperature variation of the cold stimulation device, obtained when cold stimulation was applied, and aspects of temperature variation, obtained when the device was brought into contact with the skin, were determined through the above investigated device evaluation. In order to examine the influence of such temperature variation on experimental subjects, questionnaires for the evaluation of subjective perception were administered a total of three times. The questionnaires were administered after the experiments.

However, since the present research is related to an experiment for verifying the effect obtained from a single use of the device for a short period (10 to 30 minutes) , psychological experiments for evaluating the improvement of perception were excluded. The questions in the questionnaires are given in appendix. In primary, secondary and tertiary evaluations, experiments were conducted for 6 minutes, 13 minutes and 11 minutes, respectively. Protocols for detailed evaluations are shown in FIGS. 7A to 7C. A questionnaire was constructed to divide the intensity of temperature perception into sections ranging from -2 to 2 and to allow each experimental subject to mark a corresponding section, in which the experimental subject senses temperature, at regular intervals of 30 seconds. After experiments had been terminated, experimental subjects answered corresponding questions, such as variation in mental status or perceived concentration ability during the application of stimulation, subjective aspects of variation of stimulation, wearing sensation, and pleasantness.

1.2.3 Primary experiment

Several facts can be learned through the prior research, such as the evaluation of the characteristics of the cold stimulation device and the evaluation of subjective perception of cold stimulation.

First to be learned was the fact that an effective cold stimulation period was limited to 3 minutes from when the cold stimulation device was operated to apply cold stimulation, through the observation that the experimental subjects subjectively felt pleasantness or refreshment before three minutes had elapsed, whereas they complained of pain after 3 minutes had elapsed. Therefore, in the primary experiment, experimental protocols including a total of three steps were established. At first and second steps, the experiment was conducted by applying cold stimulation to 6 experimental subjects and 3 experimental subjects, respectively, a total of four times. After confirming that the obtained experimental results at the first and second steps were generally uniform, the length of the experimental period at the first and second steps was adjusted. Therefore, at the third step, an experiment was conducted by applying second cold stimulation to 3 experimental subjects . The third step protocol was determined to be the most efficient and suitable cold stimulation experimental protocol, and thus experiments were conducted on a total of 15 experimental subjects to measure Heart rate variability (HRV) and conduct an ElectroEncephaloGram (EEG) . As a measurement instrument, the BIO amp of a Powerlap 800 of an AD instrument with

ElectroCardioGram (ECG) and EEG electrodes was used.

FIGS . 8A to 8C are views showing the protocols of the primary experiment simply conducted at the first to third steps, and FIG. 9 illustrates an actual picture showing the primary experiment conducted using the cold stimulation device according to an embodiment of the present invention.

1.2.4 Secondary experiment

In the secondary experiment, three additional experiments were conducted based on the results of the primary experiment .

1. Experiment to determine the reproducibility of the primary experiment for 15 cases (including light + auditory + cold stimulation) 2. Experiment to compare case 1 (including light + auditory stimulation) and case 2 (including light + auditory + cold stimulation)

3. Experiment to confirm the difference according to the classification of experimental subject groups (cold syndrome and heat syndrome)

4. Warm stimulation experiment on experimental subject exhibiting cold syndrome

First, the first experiment in the secondary experiment was conducted using the same protocols as the primary experiment with respect to 15 cases so as to examine the reproducibility of the primary experiment. However, the difference between the primary and secondary experiments is that cold stimulation was applied together with light + auditory stimulation in the secondary experiment.

The second experiment was an additional experiment for examining whether variation in the High Frequency (HF) of HRV can be induced using only light stimulation and auditory stimulation. In the same experimental protocols, only light + auditory stimulation was applied as first stimulation, and light + auditory + cold stimulation was applied as second stimulation.

A subsequent experiment is an experiment for examining whether aspects of variation according to stimulation vary with respect to persons exhibiting cold syndrome and heat syndrome based on cold and heat syndrome differentiation, according to the oriental medical theory differentiating between the syndromes . In order to carry out the experiment, questionnaires to determine cold and heat syndrome differentiation were provided to and filled out by experimental subjects in advance through email. After the termination of the experiment, experimental results were divided into two groups based on whether they exhibited cold syndrome or heat syndrome, and were analyzed thereby. The final experiment was an experiment for examining whether a High Frequency (HF) increases in response to warm stimulation in the case of a person exhibiting cold syndrome if temperature stimulation influences cold and heat syndrome differentiation. The principal analysis parameter of the secondary experiment was HRV, and EEG was analyzed and referred to after being measured.

1.3 Evaluation parameter for experiment 1.3.1 Heart Rate Variability (HRV)

"Heart Rate Variability (HRV)" or "heart rhythm" is a technology for measuring the variation in heart rate every second, which has recently been approved as the basis for evaluating the function of the Autonomic Nervous System (ANS) and the status of a heart beat. The ANS is the portion of the nervous system that controls the function of respective internal organs of the human body, including the heart, and automatically controls the motion of the endocrine glands and the digestive system. In addition, it is widely known that the ANS is directly influenced by the mental or emotional status of a human being and affects the interaction between parasympathetic nerves and sympathetic nerves . If a human body is in a strained state or emotionally excited state, the function of sympathetic nerves in the ANS, which is controlled regardless of the will of a human being, accelerates to increase the heart rate, dilate the pupils of the eyes or suppress the secretion of the digestive system.

Methods of analyzing HRV are classified into two types: frequency domain analysis and time domain analysis . From the standpoint of recording time, HRV analysis methods are classified into two types : "short time analysis" for performing analysis using a minimum unit of 5 minutes, and "long time analysis" for measuring and recording HRV for 24 hours and integrally analyzing HRV.

(1) Time domain analysis

When two or more pieces of heart rate data are input, the standard deviation of a heart rate is calculated using the following standard deviation equation [1] ,

where SD is the standard deviation of a heart rate, Var is a variance, HR is the heart rate that is measured and recorded, and n is the number of heart rates stored. In this case, Equation [1] is a typical expression for calculating a standard deviation.

In typical theory, it is accepted that, (as the value of a standard deviation, the status of a body is relatively healthy. In former days, it has been believed that the heart rhythm of a human body in a relaxed state is simple and regular, but actually observed heart rhythms are irregularly distributed. This is due to the active counteraction of the parasympathetic and sympathetic nerves of the ANS, so that variation in heart rate over time increases and becomes irregular as a result of the normal activity of ANS in a human body. The standard deviation of a heart rate calculated using the above equation is used as base data for analyzing a stress index to be calculated later.

(2) Frequency domain analysis

A method of performing analysis on a frequency domain on which an x axis is indicated as a frequency band is known as the most reliable method when using the "short time analysis" at the time of analyzing HRV, and has been recognized as a parameter for more precisely describing the antagonism of ANS together with the time domain analysis.

Frequency domain analysis is performed on HRV, used as a

parameter in the present research. As shown in the following table, High Frequency (HF) or HF norm, Low Frequency (LF) or LF norm, and the ratio of LF/HF are mainly observed. For example, if HF norm increases or the ratio decreases when cold stimulation is applied, it means that parasympathetic nerves are activated. In contrast, if LF norm increases or the ratio increases, it means that sympathetic nerves are activated.

Table 1

1.3.2 ElectroEncephaloGraphy (EEG)

D Principles of generation of brain waves and analysis of brain waves

(1) Brain waves

Generally, brain waves (EEG) are obtained by recording the electrical activity of nerve cells in the cerebral cortex using electrodes attached to the scalp area. EEG recording was first conducted in 1929 by a German psychiatrist named Hans Berger. He carried out basic research to clinically or experimentally apply brain waves in 1929 to 1938. Thereafter, with the development of epilepsy research, various methods of

measuring and analyzing brain waves have been developed. The amplitude of brain waves ranges from about several μV to several hundred μV, and the frequency thereof ranges from about 0.1 Hz to several hundred Hz . The basic factors of brain waves include activity, wave and rhythm. Activity denotes fluctuation in potential, and wave denotes individual element of activity. Rhythm denotes an activity comprised of waves repeated at almost uniform periods and waveforms . The amplitude is not necessarily constant, and an alpha wave is an alpha rhythm.

(2) Classification of brain waves

The types of brain waves are indicated in the following Table 2.

Table 2

(3) Analysis of brain waves

Alpha waves have a frequency from 8 to 13Hz, are generated when a healthy person relaxes, solves a problem or

performs a cognitive activity, and exhibit a regular waveform. The alpha waves appear clearly in the back part of the head, and decrease when visual stimulation is applied. Beta waves have a frequency from 13 to 30Hz, are generated when a healthy adult is excited, uneasy or strained, and can be induced by medicines such as anesthetics . If beta waves are continuously generated, the ability to make decisions is decreased, or distraction is induced. Gamma waves have a frequency from 30 to 50Hz and are generated in an awakened or excited state, and a relatively large number of gamma waves are generated from the frontal lobe and the parietal lobe.

Delta waves have a frequency lower than 4Hz, and are generated from several parts of a brain when a healthy adult sleeps. Delta waves may appear due to a brain tumor, brain inflammation, clouded consciousness, etc. Theta waves have a frequency from 4 to 8Hz and are slow waves . The fact that slow waves are dominant signifies a phenomenon in which a plurality of nerve cells existing in the cerebral cortex is simultaneously active. Theta waves are generated when a healthy adult becomes unwary and dozes off, and are involved in creative power and learning ability. The field that will be mainly observed in this research, is related to alpha waves generated when a person relaxes, solves a problem or performs a cognitive activity, as described in the above brain wave analysis. In respective temporal bands, data obtained for the same period (3 minutes) are analyzed for frequency, and total power values of alpha waves are compared to each other. The intensities of alpha waves before and after the application of stimulation

will be compared with each other.

1.3.3 Classification of cold syndrome/heat syndrome

Since the stimulation that is mainly applied in this research is temperature stimulation (cold stimulation) , a group of experimental subjects is classified according to whether they exhibit cold or heat syndrome, as per an oriental medical diagnostic method, and then a secondary experiment is conducted. A method of classifying the experimental subject group into a cold syndrome group and a heat syndrome group is described with reference to a thesis entitled "Research on the validity of the development of questionnaires for cold and heat syndrome differentiation" published in the Korean Diagnostic Institute of Oriental Medicine, Volume Six, No. 2. In the thesis, a questionnaire composed of a total of 14 question items related to cold and heat syndromes was established. Respective question items were drawn up by evaluating the degree of relevance to cold and heat syndromes with reference to medical practitioners and five books that have made a medical contribution to the establishment of differentiation according to eight principles, including cold and heat syndrome differentiation.

In a secondary experiment, a questionnaire was administered using a list of question items related to cold and heat syndrome differentiation, resulting answers to the list of question items were converted into Z-scores, and two values, respectively corresponding to a heat factor and a cold factor, were obtained through respective derivation formulas . Thereafter, the likelihood of heat syndrome (P_heat) and the

likelihood of cold syndrome (P_cold) were calculated based on the heat factor and the cold factor, thus grouping the experimental subjects.

2. Experimental results

2.1 Evaluation of cold stimulation device The graphs of temperature curves measured using a thermometer and a thermistor pod of an AD instrument are shown in FIGS. 1OA and 1OB. In the graphs of the temperature curve measured using the thermometer, cold stimulation was applied for 5 minutes after 30 seconds, as seen in a 6-minute graph in FIG. 1OA, whereas cold stimulation was applied for 18 minutes after 30 seconds, as seen in a 20-minute graph in FIG. 1OB. As shown in FIGS. 1OA and 1OB, a cooling device typically lowers a temperature of 20 to 30°C down to 5 to 15°C, which shows that the cooling device operates within limits tolerable to the human body. In the 6-minute graph, it can be seen that temperature decreases for 1 to 1.5 minutes after stimulation has been applied, and then slightly increases after 4 minutes. In order to obtain more precise characteristics, an experiment was conducted after extending an experimental period to 20 minutes. It can be seen that, in a cold stimulation period having a total duration of 18 minutes, the difference between the highest temperature and the lowest temperature was about 6 to 7°C.

However, in order to reduce error occurring due to the temperature measurement operation being manually performed, temperature was measured using the thermistor pod, and graphs

of temperature variation are shown in FIGS. 11A and HB.

Through this experiment, it can be seen that the cold stimulation device is operated within limits tolerable to the human body, and temperature slightly increases after the first 2 to 3 minutes have passed in accordance with the characteristics of the cold stimulation device.

2.2 Evaluation of subjective perception of cold stimulation An evaluation of subjective perception using a questionnaire was administered a total of three times . FIGS . 12A to 12C illustrate the averages of temperatures subjectively sensed by experimental subjects in three cold stimulation protocols . In the graphs, cold sensation and warm sensation are indicated on upper and lower portions around zero, respectively, and the vertical axis indicates standard deviation.

Based on responses to a questionnaire administered after the cold stimulation has been applied, the stimulation intensity, stimulation period, and stimulation interval required to suitably apply cold stimulation can be estimated. Results, indicating that a suitable stimulation period for cold stimulation is 10 minutes and a suitable stimulation interval is 1 minute, were obtained. Further, it can be seen that the subjective perception of experimental subjects to temperature has a tendency toward improving concentration ability rather than unpleasantness. However, statistical analysis was not performed because the number of samples was small . With respect to the sensation experienced when wearing the device,

more than half the experimental subjects felt uncomfortable due to the tightening of a band or the weight of the device.

2.3 Primary experiment In 9 cases in which an experiment comprising a total of two steps of experimental protocols was conducted, relatively- definite results for the human body were obtained, as shown in FIGS. 13A and 13B. As a result of the experiment, it can be seen that parasympathetic nerves are activated and sympathetic nerves are suppressed by suitable cold stimulation.

The results of the experiment conducted using the experimental protocols, which was finally determined after two steps of experiments, are shown in FIG. 13C.

FIG. 13C shows that the ratio of LF/HF greatly decreased during a first cold stimulation period. Such a numeric value shows that the ratio was maintained during a non-stimulation period of 1 minute and a second cold stimulation period of 3 minutes, and was then increased again during a non-stimulation period of 5 minutes . Through the experiment, the fact that cold stimulation activates parasympathetic nerves was confirmed. However, of 15 cases, only 10 cases showed a clear increase in HF, and the remaining 5 cases did not show an increase in HF. Further, the results of the measurement of EEG exhibited no variation depending on whether cold stimulation was applied in the primary experiment.

2.4 Secondary experiment

In the above primary experiment, the fact that cold stimulation activates parasympathetic nerves to increase HF,

which is a parameter of HRV, was learned. The results of the secondary experiment that was additionally conducted based on this fact are described.

First, an experiment for applying light + auditory + cold stimulation to experimental subjects and measuring reproducibility of the experimental results of the primary experiment, which showed that, of 15 cases, 10 cases exhibited an increase in HF, was conducted on 15 cases, similar to the primary experiment. The results of the secondary experiment showed an increase in HF and a decrease in the ratio over all 15 cases . These results somewhat show that cold stimulation activates parasympathetic nerves, but, if cold stimulation is applied together with light + auditory stimulation, the parasympathetic nerves can be more definitely activated. Consequently, a device using light + auditory + cold stimulation together can be considered to more sufficiently activate and stabilize parasympathetic nerves, compared to a device using only cold stimulation. Therefore, the first experiment in the secondary experiment is considered to have obtained successful results through the experiment for measuring the reproducibility of the primary experiment. FIG. 14 is a view showing the average of ratios for 15 cases.

Second, comparison experiments for light + auditory stimulation and light + auditory + cold stimulation were conducted on 4 experimental subjects. In the case of all four experimental subjects, a clear increase in HF was exhibited in response to light + auditory + cold stimulation. In the case of 2 experimental subjects, an increase in HF was not exhibited in response to light + auditory stimulation. In the case of

the remaining 2 experimental subjects, an increase in HF was exhibited, but, in the case of one of them, the range of variation was not large compared to the case where cold stimulation was additionally applied. Consequently, when cold stimulation was additionally applied, variation in HRV was exhibited by 100% of the experimental subjects, whereas when only light + auditory stimulation were applied, variation in HRV was exhibited by 50% of the experimental subjects. Next, a cold stimulation experiment based on the classification of experimental subject groups (cold syndrome and heat syndrome) was conducted in the following two ways.

1. Conduction of a cold stimulation experiment three times on individual cases exhibiting cold syndrome and heat syndrome

2. Conduction of a cold stimulation experiment on 10 cases exhibiting heat syndrome and 5 cases exhibiting cold syndrome

First, in the first experiment, a clear decrease in the ratio was exhibited three times with respect to the case exhibiting heat syndrome, whereas a decrease in the ratio was generally exhibited with respect to the case exhibiting cold syndrome, but the range of variation was not large compared to the case exhibiting heat syndrome. However, since this experiment was a preliminary experiment, and was conducted on a single case for each syndrome, there is a limitation on statistical analysis. The results of the second experiment on 15 cases will be described later after the graph of FIG. 15. A graph showing the comparison of the averages of the results of

experiments, done three times, is shown in FIG. 15.

The ratio of LF/HF in cold stimulation was analyzed with respect to 10 cases exhibiting heat syndrome and 5 cases exhibiting cold syndrome, of 15 cases, based on the above- described repeated experiments . An. interesting fact was confirmed, in which a ratio value, which decreased in response to first stimulation and increased in response to second stimulation in the case of cold syndrome, and in which a ratio value further decreased in response to second stimulation compared to first stimulation in the case of heat syndrome. This shows that the HF norm further increases in response to second stimulation compared to first stimulation in the case of heat syndrome, which generally means that a person exhibiting heat syndrome gradually positively reacts to stimulation, that is, cold stimulation (in this case, large variation in the ratio is considered to be positive) . In contrast, it shows that HF norm decreases in response to second stimulation compared to first stimulation in the case of cold syndrome, which generally means that a person exhibiting cold syndrome reacts increasingly negatively to cold stimulation. The resultant graph of the experiments is shown in FIG. 16.

Finally, an experiment for applying warm stimulation, instead of cold stimulation, to 4 experimental subject cases exhibiting cold syndrome was conducted. The resultant graph is shown in FIG. 17.

As shown in FIG. 17, only when an experimental subject is exhibiting cold syndrome does the ratio of LF/HF decrease even in response to cold stimulation, it can be seen that the ratio of LF/HF decreases somewhat in response to second

stimulation compared to first stimulation and increases after the application of stimulation has been terminated. This supports the notion that temperature stimulation influences experimental results to some degree depending on the exhibition of cold or heat syndrome by a person. However, since the number of experimental cases was only 4, there is a need to increase the number of experimental subjects and additionally carry out experiments on the experimental subjects.

3. Consideration and conclusion

Through the above research, the following facts could be obtained.

(1) It was disclosed that cold stimulation applied to a suitable degree and at suitable intervals (above 3 minutes) did not induce unfavorable effects on the human body as a result of experiments of subjective perception and device characteristics. This fact has been proven by prior research.

(2) Cooling intensity within a specific range and periodic cold stimulation within a specific range induced physiological variation in a human body. When the principal aspects of such physiological variation are observed through HRV, the physiological variation can activate parasympathetic nerves and suppress sympathetic nerves, which means that the human body is relaxed. Such results were exhibited relatively clearly. The results of a total of two stimulation experiments support the fact.

(3) As a result of the experiment of subjective perception of cold stimulation, it can be confirmed that the time and frequency of cold stimulation that are most suitable

and efficient are two cold stimulations, each applied for 3 minutes of a total of 17 minutes in the final protocol, as shown in FIG. 18. Further, it can be seen that the intensity of stimulation most suitable to experimental subjects in the protocol is a degree causing external temperature to decrease 5 to 15°C, in the temperature evaluation for a stimulation device. Further, a confirmed interesting fact is that the reaction to stimulation is exhibited differently in coordination with the preference of stimulation, depending on whether each experimental subject exhibited cold or heat syndrome.

4. However, brain waves (EEG) , observed as a parameter together with HRV, did not exhibit clear results or any special significance . 5. As a result of observation performed through the progress of the present research, a suitable degree of cold stimulation applied to the region of the forehead is determined to positively influence the human body, and differences between the effects of a plurality of stimulation aspects on the human body should be later clarified through more detailed investigation.

[Industrial Applicability]

As described above, the present invention provides a method of controlling the temperature of a cold/warm forehead massage device, which can apply different currents to a thermoelectric element at different periods, thus transferring cold/warm stimulation to the skin in consideration of the

physiological characteristics of the human body, and minimizing power applied to the device.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims .