Ryodoraku Medicine and Stimulus Therapy
Vol.2: 1 - 17 ,2019

iARMS
Review article
Ryodoraku Medicine and Stimulus
Therapy is an International,
peer-reviewed scientific journalthat publishes original article inexperimental and clinical medicine
for Ryodoraku Medicine

Relationship between "Pain sensation" and" Ryodoraku measurement (Skin energizing current) "by principal component analysis

Hiroshi END LAc,PhD,

Kurashiki University of Science and The Arts.
Department of Life and Health Science＜Major of Acupuncture and Moxibustion＞
Official Journal of International
Association of Ryodoraku
Medical Science（社）国際良導絡医学会雑誌

Abstract
In the area of "acupuncture points" (on the skin) in Oriental medicine, weak potential fluctuations and changes in electrical conductive resistance are manifested. In addition, the change inelectrical conductive resistance also appears in a band on the body surface in "meridians" formedby the acupuncture points. At present, they are called "Ryodoraku medicine" or "Ryodoraku autonomics", and basic and clinical research is being conducted. Besides, the electrical conductive
resistance of the skin also fluctuates when feeling pain. Therefore, attempts have been made touse the fluctuation as an indicator of "pain sensation". But "pain" is a subjective sense and experience, and individual differences are also combined. Therefore, objective indicators of pain are
considered to be extremely difficult.
So far, we have researched statistically on the relationship between "pain sensation" and "Ryodoraku medicine (i.e., resistance to skin electricity in the extremities)". In this study, the results ofthree experiments were integrated and discussed: first, before and after needle stimulation, second, without stimulation, and third, for experimental animals. In conclusion, regardless of humanor animal, if the electrical resistance of the hand or foot (limb) fluctuates significantly, it is associated with the sensitivity to pain. The "pain sensitivity" was suggested to increase when theelectrical resistance of the hand (forelimb) was low and the electrical resistance of the foot(hindlimb) was high.

I. Introduction
Our bodies are given various stimuli fromnature. The skin, in particular, is the site thatreceives many of its stimuli. However, theskin has a mechanism that protects the bodyagainst external stimuli. It is no exception toelectricity.
Originally, the skin has the property that
it is difficult to conduct electricity. In particular, when the surface of the skin is dry,electricity hardly passes. However, different
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Ryodoraku Medicine and Stimulus Therapy
Vol.2: 1 - 17 ,2019parts of the skin, such as the face, back,palms and feet, have differences in the ease ofpassing electricity. Such differences are also
manifested by pathological (abnormal) conditions of the skin 1).
Generally, in the body part, the face is easier to conduct electricity than the limbs andtrunk. In the skin, especially in the hands
and feet, the palm passes electricity moreeasily than the limbs (haired areas of thearms and legs). However, anywhere on thebody, where the skin surface is damaged, evenweak electricity will pass easily. In addition,in the case of psychological, physiological or
pathological changes in the body, electricity
can easily pass through 2). Using this phenomenon, that is, the phenomenon in whichelectricity easily passes through the skin,Attempts have been made to acquire various
biological information and apply it to therapy.
In particular, the fluctuation of skin potential,
which is one of the electrical phenomena on
the body surface, has already been applied in
the fields of medicine and psychology. It is
well known today that in finger tips andpalms, a potential difference (GSR) occurs in
response to psychological changes3). In addition, in the part of called "acupuncture point(meridian point)" in oriental medicine, thepotential fluctuation and the change of theskin electrical resistance (conductive current)
similar to the above are observed 4). "Acupoint search" is performed through weakcurrent to skin based on the electrical fluctuation. Furthermore, this method is called"Ryodoraku (phenomenon)" and is considered
as a method of scientific exploration of "Meridians". Currently, this Ryodoraku phenomenon has developed into "Ryodoraku
measurement" and "Ryodoraku treatment" 5)
Fig. 1-1).
Especially in Ryodoraku treatment,
the skin electrical resistance reduction point
appearing at a site similar to the “Acupuncture point” is referred to as “Reactive Ryodo
Point”, Stimulation therapy using electricity
at the site has found clinical usefulness 6).
In addition, attempts have been made toapply changes in skin surface current causedby pain as an objective indicator of "painsensation" 7).

Fig.1-1 Functional route of Ryodoraku meridians(Related organs)

Ryodoraku meridians are situating with body and limbs
by 3 same as traditional meridian (there are 24 lines withthe front and the back, right and left). But the connection
route are different meridians with traditionally and Ryodoraku a little (understand a technical book in detail). When() organ shows abnormality, electrical skin resistance on
Ryodoraku meridians increases and decreasing.

However, "pain" is a subjective sensory
phenomenon or sensory experience. Therefore,
objective judgment of pain sensation is very
difficult. In particular, various psychologicaland physical conditions are added, and theirsuperposition increases the uncertainty of thesense of pain. Furthermore, if individual differences in pain sensation are added, it isnatural that objectification of pain sensations
becomes increasingly difficult 8).
Even in the international organization for
pain research, "The International Association
for the Study of Pain (IASP)", an objective indicator of pain sensation has not yet been obtained 9).
In this study, we focused on changes in skinelectrical resistance in the extremities andstatistically examined the relationship between many skin electrical resistance partsand pain sensation (pain threshold) in ourprevious research.
This time, the results of the following threeexperiments are summarized from the same
viewpoint from those studies.
① A Study of Pain Threshold by The Ryodoraku(i.e., Meridian) Current Measurement.
--Relation of Ryodoraku and Pain, before /after Low Frequency Electrical Acupuncture(LFEA)-- 10)

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Ryodoraku Medicine and Stimulus Therapy
Vol.2: 1 - 17 ,2019② Conjecture of pain sensibility by Ryodoraku"i.e.,Meridian" measurement (skin surface
current) 11)③ Relation with Animal Limbs Skin Surface
Current and Pain Threshold 12)

II. Methodｓ① A Study of Pain Threshold by The Ryodoraku (i.e., Meridian) Current Measurement.
Low Frequency Electrical Acupuncture(LFEA) was performed for 20 minutes for
20 subjects (healthy volunteers). Low
Frequency Electrical Acupuncture was apulse stimulation with a frequency of 3 Hz(continuation), which is widely used in
acupuncture anesthesia method. The
punctured acupuncture points were theacupuncture points H64 (LI4: large intestine; Hegu, 大腸; 合谷), F69 (ST36: stomach; Zusanli, 胃 ; 足 三 里 ), and Auris-acupoint (M51, 交感). During stimulation with Low Frequency Electrical Acupuncture, Pain Threshold (PT) and Ryodoraku Current (RC) as skin electrical resistance and/or skin surface current were
measured 13), Fig. 2-1-1).

② Cathode conductor (grip): It is a hand grip for stabilizing the measurement electrode, and the materialis plastic for insulation.
③ Ammeter: Up to 200 μA can be displayed.
④ Variable resistance: The load current to be supplied
can be adjusted manually.
⑤ Voltage conversion switch: Switch to three voltagesof 6 V / 12 V / 21 V according to various environmental conditions.
⑥ Rated power supply: To obtain a stable voltage /current, usually use dry cell (voltage 1.5 V and 9 V)
in combination.
⑦ Anode (Dry Electrode) Conductor (Grip): To enlarge
the contact area, use a cylindrical metal rod (approximately 2 cm in length, 10 cm in length) andgrasp with a palm.

The pain threshold was measured using
a pressure pain meter <F.P.meter> Fig. 2-1-2)
manufactured by Kyoto Pain Research Institute Model -7. In the measurement procedure, as shown in the figure, the examiner's fingers and F.P.meter pinched andpressed the subject's body flank, andmeasured the tenderness <Kg / cm2 / 0.5
sec> at that time 14), Fig. 2-1-3). The pain
threshold was measured 5 times during
stimulation with Low Frequency Electrical
Acupuncture. The measurement interval
was before operation and 5 minutes, 10
minutes, 15 minutes, and 20 minutes after
the start of stimulation (after the end ofenergization).

Fig.2-1-2 Finger Pressure (F.P.) meterFig.2-1-1 Ryodoraku current measurement

Energize a specific body surface (skin) and measure thecurrent flowing immediately after energization. The current
to be loaded is extremely weak, and it hardly feels thatcurrent.
The initial setting is described below.
① Cathode (wet electrode): It is filled with cotton
soaked in physiological saline. Directly touch therepresentative measurement point and measure thecurrent. The contact area is defined to be about 1 cm
2.

It is used for simple pain threshold measurement.
F.P.meter can mechanically reproduce the fingertip compression of human and can measure the pressing force.
When the tip of the equipment (made of rubber hemisphere)is pressed against the surface of the body, the indicator bar
displays its degree of pressing (Kg). Stop pressing when thesubject feels pain. Even if pressing is stopped and theequipment is released, the instructing bar stops at that
position and does not return.

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Fig.2-1-3 Measuring method of presser pain

We sandwiched the body (side flank) of subjects with F. P.
meter and pushed at a speed of 0.5 kg / sec. The subject wasordered to tell us when it felt pain by pressing. We measured
the degree of pressing (Kg) at that time. The measurement
was performed three times, and the average value was set
as a pain threshold.

The measurement of Ryodoraku current
used Neurometer D-401 Fig. 2-1-4) (made by
Neuro Medical Industries, Ltd.). The initial setting of the measuring instrument
was a voltage of 12 V (direct current) and acurrent of 200 μA (during short circuit).
The measurement site was the representative measurement points on the left
and right (total 24 points) considered toreflect the activity of Ryodoraku (12 lines)
Fig. 2-1-5).

Fig.2-1-5 Representative Measurement Point(RMP) of each Ryodoraku meridians

Ryodoraku researchers are thinking that current valuesof representative measurement points reflect the state of
Ryodoraku meridians. Representative measurement points
are located the palm side and back side on the wrist, insideand outside of the feet. There are three points respectively(total 24 points).

In the measurement procedure, the skinsurface current (μA) was measured after
0.75 seconds when energized.
The current measurement with this setting is known as the normal Ryodoraku
current measurement Fig. 2-1-6). After measurement, for clinical use, the obtained
current values are plotted on a chart for
Ryodoraku. Diagnose the condition of thechart according to a certain standard, anddecide the treatment guideline Fig. 2-1-7).

Fig.2-1-4 Neurometer (D-401)

In Ryodoraku measurement, the cathode conductor with 1
cm 2 skin contact surface is normally charged with 12 V, 200
μA (short circuit) electricity, and the current after 0.75 sec ofenergization is measured. This instrument is designed toperform digital display of current.

Fig.2-1-6 Measurement by Neurometer (D-401)

In Ryodoraku measurement, the current value at the
representative measurement point on the hand part and the4
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Ryodoraku Medicine and Stimulus Therapy
Vol.2: 1 - 17 ,2019foot part is measured. For the representative measurement
points, measure H1 to F6 in the left and right order. The
measuring conductor (cathode) of this instrument is designed to have a pressing force of 60 g.

first, and then the pain threshold wasmeasured.
③ Relation with Animal Limbs Skin Surface
Current and Pain Threshold.
For the experiment, eight hairless rats
(Wistar strain: Hair-less Rats) of 6 weeks
old (♂) were used, and the pain thresholdand skin electrical resistance were measured in these rats.
The pain threshold was measured using
a radiant heat pain threshold meter (KudoElectric Co., Ltd.) called "Nakahama type
pain meter NYT-5". The radiation site wasat the center of the rat tail. The measurement procedure was to measure the incubation time <300 mcal / cm2 / sec > of
avoidance behavior (Tail Flick Latency)
against thermal pain when irradiated withradiant heat 15) Fig. 2-3-1).

Fig.2-1-7 Ryodoraku's dedicated chart

During Ryodoraku therapy, the measured current values
are plotted as an indicator for diagnosis and treatment
policy decision.

② Conjecture of pain sensibility by Ryodoraku "i.e.,Meridian" measurement (skinsurface current).
The pain threshold and Ryodoraku current as a skin conduction resistance were
measured in 23 subjects (healthy volunteers).
The pain threshold was measured bypressing the body flank with an F.P. meterand measuring the tenderness <Kg / cm2 /0.5 sec> at that time Fig. 2-1-2), Fig. 2-1-3).
The current measurement of Ryodoraku
applied voltage 12V (direct current), current 200μA (during short circuit) to therepresentative measurement point, andmeasured skin surface current value (μA)
at that time 0.75 seconds after energization Fig. 2-1-4) , Fig. 2-1-5).
In other words, the pain threshold and
Ryodoraku current were measured by thesame measurement method as in Case the① . However, the Ryodoraku current
measurement was concerned about themeasurement by the pain threshold.
Therefore, at the time of experiment, theRyodoraku current value was measured

Fig.2-3-1 Measurement of pain threshold of Rat

Rats under no anesthesia were kept in a dark place case,
Using the "Nakahama type radiant heat algesiometer (PainMeter NYT-5)", radiant heat of 300 mcal / cm 2 / sec wasirradiated to the center of the rat tail and the Tail-flick wasmeasured. The measurement was performed three times,
and the average value was set as a pain threshold.

The measurement was performed threetimes for one rat, and the mean value ofthe three measurements was taken as thepain threshold.
Pain threshold measurement was performed without anesthesia. However, skinsurface current as a skin electrical resistance was measured under anesthesia.
Anesthesia was an ether inhalation
method that is rarely used today.
Hairless rats were suitable for measuring skin surface current because they had
few body hairs. The measurement of skinsurface current used the method according
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to Ryodooraku current measurement.
Therefore, the Neurometer D-401 Fig. 2-1-4)
was used as in the case of the ①. Electrodes for electroencephalogram were attached to the inside and outside (eightplaces) of the rat's forelimb and hindlimb,
and the skin surface current value (μA)
was measured Fig. 2-3-2).

Fig.2-3-2 Rat skin surface current measurement

To contact the electrode on the skin, hairless rats without
body hair were used for the measurement. The rats wereanesthetized by aspiration (ether), then the electroencephalogram electrodes were attached to the volar side and dorsal side of the fore limb end and inside and outside of thehind limb end. These eight electrodes were used as cathodes(-). Also, a 3 x 5 cm wet electrode was stuck on the abdomen.
The electrode was an anode (+). Similarly to Ryodoraku
measurement, electricity of 12 V, 200 μA (when short circuited) was applied, and the current after 0.75 sec of energization was measured.

As in the case of the ②, we are concerned about the influence on skin surface
current measurement by measurement ofpain threshold (Pain caused by radiantheat), and at the time of the experiment,
we first measured skin surface current andthen measured pain threshold.
StatFlex 4.2 (Artech Inc.) was used for statistical analysis. Basic statistics and Welch's t
test 16) and Principal Component Analysis;
PCA 17), which is one of multivariate analysis,
were performed with each pain threshold andeach Ryodoraku current value (skin surface
current value) as variables.
The analysis procedure was performed asfollows.
First, basic statistics of pain threshold and
Ryodoraku current value (skin surface current value) in Experiment the ①, ② and ③
were calculated. Next, the pain threshold ofeach experiment was compared by means of

Welch's t test. After that, principal component
analysis was performed using the pain
threshold and Ryodoraku current value (skinsurface current value) as variables for eachexperiment. The criteria for the principal
components used in principal component
analysis were set to 1 or more for Eigenvalue
and 70% or more for the cumulative contribution rate.
In principal component analysis, we selected the principal component that was related to the pain threshold by the magnitude
and direction of the pain threshold and the
Eigenvector of Ryodoraku current (skin surface current). The principal component closely
related to the pain threshold selected in principal component analysis further calculated
the Principal Component Score.
In the principal component score, actual
measurement values that reflect the characteristics of the principal component are displayed. The principal component scores weredivided into positive and negative groups 18).
Thereafter, the measured values of pain
threshold in both groups were compared byt-test. The test used a significance rate of 5%(p<0.05). All these experiments were conducted based on the IASP's ethical guidelines19, 20).

III. Results① A Study of Pain Threshold by The Ryodoraku (i.e., Meridian) Current Measurement.
The mean ± standard deviation of Ryodoraku current values (skin surface current values) and pain threshold before andafter stimulation with Low Frequency
Electrical Acupuncture (LFEA) is illustrated. After stimulation, Ryodoraku current values were generally increased byabout 10 μA Fig. 3-1-1). Also, the pain threshold significantly increased between before
and 20 minutes after stimulation Fig. 3-1-2).
However, there was no significant relationship between Ryodoraku current value
and pain threshold in the measured values
before and after the measurement. Therefore, the relevance was left to examinationby principal component analysis.
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doubled by energization for 20 minutes. This means that thepain sensitivity has been halved by energization.

In principal component analysis, theprincipal components with relatively higheigenvalues were the first to third principal components Fig. 3-1-3). Therefore, we analyzed the relationship between pain
threshold and Ryodoraku current value ineigenvectors of the first to third principal
components.

Fig.3-1-1 Comparison of Ryodoraku current value(measured value) before and after stimulation

The current values of all Ryodoraku were higher after
stimulation than before stimulation. Relatively, H1, H5 werehigh, H3, F5 were low.

Fig.3-1-3 Eigenvalue (Contribution rate) of before
and after stimulation

Both before and after stimulation, the first principal component (z1) was the highest eigenvalue, accounting for nearly
half of the whole. After that, each eigenvalue after the second
principal component (z2) decreased successively. Eigenvalues
are also contribution rates, so the magnitude of eigenvalues ofeach principal component reflects the degree of influence on
the measurement. The principal component after the fourthprincipal component (z4) had an eigenvalue of less than 1,
therefore eigenvalues up to the third principal component (z3)were used for analysis.

Fig.3-1-2 Comparison of pain threshold before andafter stimulation
A. Changes with time of pain threshold
The pain threshold value gradually increased with thepassage of the energization time (minutes) from the stimulation. The pain threshold continued to increase by approximately 1 Kg every 5 minutes after stimulation.
B. Pain threshold (presser pain) before and after stimulation
The pain threshold was about 3 Kg before stimulation, but
it increased significantly (p<0.01) to about 6 Kg after stimulation (after 20 min). In other words, the pain threshold was

Before stimulation, no principal component was found to be related between thepain threshold and the Ryodoraku current
value. After stimulation, a significant relationship was found between pain
threshold and Ryodoraku current values in
the first and second principal components.
However, no relationship was found between pain threshold and Ryodoraku current value in the third principal component.
The eigenvectors of the first principal
component were eigenvectors where Ryodoraku current values increased or decreased uniformly Fig. 3-1-4). There was asignificant difference (p<0.05) in the pain
threshold between positive value group
and negative value group according to theprincipal component score of the firstprincipal component Fig. 3-1-5).
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the principal component score of the second principal component Fig. 3-1-7).

Fig.3-1-4 Eigenvectors before and after stimulation in the first principal component

All eigenvectors showed positive values before and after
stimulation. Therefore, all Ryodoraku current values fluctuate in the same direction. However, most eigenvectors are low(around 0.2).

Fig.3-1-6 Eigenvector before and after stimulation in the second principal component

Both before and after stimulation, eigenvectors showed
positive values in most of the H system (on the wrist),
however most of the F system (on the feet) showed negativevalues. Therefore, the Ryodoraku current value in the system of H and F fluctuates in the opposite direction. In particular, the eigenvectors of H4 to H6 were relatively high (0.3
or more).

Fig.3-1-5 Pain threshold of positive / negative
principal component score in the first principal component after stimulation

The pain threshold was about 7 Kg for the positive value,
but about 4 Kg for the negative value. There was a significant difference (p<0.05) between the pain thresholds ofpositive / negative values.

The eigenvectors of the second principal
component were eigenvectors in which
Ryodoraku current values in the upper andlower limbs both increased or decreased inpositive and negative values. Among them,in the upper limbs, eigenvectors of H4 (SI:small intestine), H5 (TE: triple energizer)
and H6 (LI: large intestine) were increased
in comparison with the others. However, inthe lower limbs, the eigenvectors of F2 (LR:liver) and F3 (KI: kidney) were decreased
compared to the others Fig. 3-1-6).
There was a significant difference (p<0.05) in the pain threshold between thepositive and negative groups according to

Fig.3-1-7 Pain threshold of positive / negative principal component score in the second principal component after stimulation

The pain threshold was about 7 Kg for the positive value,
but about 4.5 Kg for the negative value. There was a significant difference (p<0.05) between the pain thresholds ofpositive / negative values.

The eigenvector of the third principal
component was an eigenvector in which
Ryodoraku current values were divided
into positive value and negative value
specifically in the upper and lower limbs
and also inside and outside Fig. 3-1-8). There
was no relationship between pain threshold in the positive and negative groups by
the principal component score of the thirdprincipal component.
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Fig.3-1-8 Eigenvector before and after stimulation in the third principal component

The eigenvectors showed positive or negative values regardless of H system and F system before and after stimulation. Therefore, the Ryodoraku current value in the H andF system fluctuates in various directions. In particular, theeigenvectors of F system were relatively high values.

② Conjecture of pain sensibility by Ryodoraku "i.e.,Meridian" measurement (skinsurface current).
The subject's age, pain threshold andbasic statistics of all Ryodoraku currents
were listed. The left side of the table also
shows the name of meridian (alphabeticcode) Table 1). In addition, the average value± standard deviation of all Ryodoraku
current values is illustrated in Fig. 3-2-1).
Table 1
Descriptive Statistics of each Ryodoraku meridian

Fig.3-2-1 Mean current of each Ryodoraku
meridian

Ryodoraku current value (measured value) The averagevalue of each Ryodoraku current was around 30 to 40 μA.
Relatively H2, H3, H4, F5 were low values.

The principal components with relatively high eigenvalues in the principal
component analysis were the first to thirdprincipal components Fig. 3-2-2). The relationship between pain threshold and Ryodoraku current value was analyzed in the
eigenvector of each principal component.
The first principal component was an
eigenvector in which all Ryodoraku current values increased or decreased uniformly. The first principal component was
not related to pain threshold and Ryodoraku current value Fig. 3-2-3).

The average age of subjects was 23.7 years old, the average pain sensation threshold was 2.7 Kg. Each Ryodoraku
from H1L to F6R shows the name of the corresponding meridian.

Fig.3-2-2 Eigenvalues (contribution rate)

The first principal component (z1) was the highest eigenvalue, accounting for nearly half of the whole. After that,each eigenvalue after the second principal component (z2)decreased successively. Eigenvalues are also contribution
rates, so the magnitude of eigenvalues of each principal
component reflects the degree of influence on the measurement. The principal component after the fifth principal
component (z 5) had an eigenvalue of less than 1. However,the cumulative contribution rate reached 70% or more up to
the third principal component. Therefore, eigenvalues up to

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the third principal component (z3) were used for analysis.

Fig.3-2-4 Eigenvector of the second principal
component

Eigenvectors showed positive values for all H series (onthe wrist). However, all of the F system (on the foot) showednegative values. In other words, the eigenvectors of thelimbs showed completely opposite directions. Therefore, theRyodoraku current value in the system of H and F fluctuates in the opposite direction. In particular, the eigenvectorof F3 was a relatively high value (0.3 or more).

Fig.3-2-3 Eigenvector of the first principal
component

All eigenvectors showed positive values. Therefore, all
Ryodoraku current values fluctuate in the same direction.
However, most eigenvectors are low (around 0.2).

The second principal component was an
eigenvector in which Ryodoraku current
values increased or decreased in positive
and negative values in the upper and lower
limbs. The eigenvectors of Ryodoraku current values of H4 (SI: small intestine), H5(TE: triple energizer), H6 (LI: large intestine) mainly increase in the upper limbs,
and F1 (Sp: spleen), F3 (KI: kidney) in thelower limbs The eigenvector of the Ryodoraku current value decreased Fig. 3-2-4). The
second principal component was strikingly
related to the pain threshold and Ryodoraku current value. The measured data ofpain threshold for the second principal
component showed a significant difference(p<0.01) between the positive and negativevalue groups due to the principal component score for the second principal component Fig. 3-2-5).

Fig.3-2-5 Pain threshold of positive / negative
principal component score in each principal
Component
z1. Pain threshold of positive / negative principal componentscore in the first principal component
The pain threshold was about 2 to 3 Kg. There was no
significant difference between the pain thresholds of positive / negative values.
z2. Pain threshold of positive / negative principal componentscore in the second principal component
The pain threshold was about 3.5 Kg for the positive value,
but about 2.5 Kg for the negative value. There was a significant difference (p<0.01) between the pain thresholds ofpositive / negative values.
z3. Pain threshold of positive / negative principal componentscore in the third principal component
The pain threshold was about 2 to 3 Kg. There was no
significant difference between the pain thresholds of positive / negative values.

The third principal component was an
eigenvector in which the skin surface current value increased or decreased specifically in the upper and lower limbs and also
in the inside and outside. The third principal component was not related to thepain threshold and the skin surface current value Fig. 3-2-6).

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Fig.3-2-6 Eigenvector of the third principal
component

Regardless of H system or F system, eigenvectors showedvarious positive or negative values. Therefore, the Ryodoraku current value in the H and F system fluctuates invarious directions. In particular, some eigenvectors of the H
system were relatively high values.

③ Relation with Animal Limbs Skin Surface
Current and Pain Threshold.
Basic statistics of pain threshold andskin surface current of fore and hind limbs
are listed Table 2), and the mean value ±standard deviation of all skin surface current values is illustrated Fig. 3-3-1).
Table 2
Descriptive statistics of each skin surface current andpain threshold

Each skin surface current value was between 60-140 μA.
It was larger than human's value, and the average pain
threshold was 8.6 seconds.

Fig.3-3-1 Skin surface current value of each limb
(measured value)

The average value of each skin surface current wasaround 100 μA. Relatively, the deviation was small.

Furthermore, the change of the meanvalue of the pain threshold measured threetimes is illustrated. In the measurement ofpain threshold, slight differences were observed in the first and third times. However, no significant difference was related
between the first and third times Fig. 3-3-2).
The analysis values were confirmed bylisting the eigenvalues and contribution
rates and cumulative contribution rates ofeach principal component Table 2). The principal components having relatively higheigenvalues calculated by principal component analysis were the first to thirdprincipal components Fig. 3-3-3).

Fig.3-3-2 Changes in pain thresholds measured
three times

The initial pain threshold was around 10 seconds, butlater it was around 8 seconds. However, there was no significant difference between each.

Table 2
Eigenvectors of the measurement part in each principal component

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The eigenvalue of the first principal component was 4.13,
and the contribution rate (cumulative contribution rate) was
about 52%. Approximately 50% of the variation characteristics of skin surface current appears in this principal component. The eigenvalue of the second principal component
was 1.24, the contribution rate was about 16%, and thecumulative contribution rate was 67%. The eigenvalue ofthe third principal component was 0.8, the contribution rate
was about 10%, and the cumulative contribution rate was77%. Therefore, as much as 77% of the variation characteristics of skin surface current appears up to this third principal component.

Fig.3-3-4 Eigenvector of the first principal
component

All eigenvectors showed positive values. So, all skin surface
current values fluctuate in the same direction. However, theeigenvector of the right hind limb is relatively low (0.3 orless).

The second principal component was an
eigenvector in which skin surface current
values increased or decreased in positive
and negative values groups in the fore andhind limbs. The second principal component was significantly related to the pain
threshold and the skin surface current
value Fig. 3-3-5).
The measured data of pain threshold forthe second principal component recognizeda significant difference (p<0.05) between
the positive and negative value groups
based on the principal component score of
the second principal component Fig. 3-3-6).

Fig.3-3-3 Eigenvalues and Contributions ratio of
Each Principal Component

The analysis criterion is an eigenvalue of 1 or more or acumulative contribution ratio of 70% or more.
Therefore, since the eigenvalue of the third principal component is less than 1, analysis was made up to the second
principal component.

The first principal component was an
eigenvector in which the skin surface current value increased or decreased uniformly. No correlation was found between
pain threshold and skin surface current in
the first principal component Fig. 3-3-4).

Fig.3-3-5 Eigenvector of the second principal
component

Eigenvectors showed negative values in forelimbs andpositive values in hindlimbs. In other words, the eigenvectors of forelimb and hindlimb completely showed the
opposite direction. So the skin surface current values offorelimb and hind limb vary in opposite direction.

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Ryodoraku Medicine and Stimulus Therapy
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Fig.3-3-7 Eigenvector of the third principal
component

Regardless of forelimb / hindlimb, eigenvectors showedvarious positive or negative values. So the skin surface
current values in forelimb and hind limb vary in various
directions. In particular, some eigenvectors were relatively
high values.

IV. Discussions

Fig.3-3-6 Pain threshold of positive / negative
principal component scores in each principal component
z1. Pain threshold of positive / negative principal componentscore in first principal component
The pain threshold was about 7 to 8 seconds. There wasno significant difference between the pain sense thresholdsof positive / negative values.
z2. Pain threshold of positive / negative principal componentscore in the second principal component
The pain threshold was about 5 seconds for a positive
value, but it was about 8 seconds for a negative value. A
significant difference (p <0.05) was recognized between
positive / negative pain sense thresholds.
z3. Pain threshold of positive / negative principal componentscore in third principal component
The pain threshold was about 6 to 7 seconds. There wasno significant difference between the pain sense thresholdsof positive / negative values.

The third principal component was an
eigenvector in which the skin surface current values in the fore and hind limbs andthe inside and outside increased or decreased separately. The third principal
component was not related to pain threshold and skin surface current value Fig. 3-3-7).

The following the ① , ② and ③ experiments can estimate the relationshipbetween pain threshold (i.e., pain sensitivity) and skin electrical resistance orskin surface current value (i.e., Ryodoraku
current value) by solving a linear algebra
composed of fluctuating current value inskin electrical resistance measurement
and eigenvectors of principal components
obtained by principal component analysis
Fig. 4-1-1).

Fig.4-1-1 The equation that eigenvalue is calculated with principal component analysis

Each Ryodoraku current subtracts the mean, and multiplies eigenvector in the value. The summation becomes
eigenvalue, and, in other words, this is linear algebra toconsist of Ryodoraku current, the mean and eigenvector.
Principal component that eigenvalue is big reflects diagnostic character of Ryodoraku.

① A Study of Pain Threshold by The Ryodoraku (i.e., Meridian) Current Measurement.
Before stimulation, the fluctuation ofskin surface current values in the first to
third principal components was not related
to the pain threshold. Therefore, it wasthought that there was no relationshipbetween the two measured values..
After stimulation, the fluctuation of skinsurface current values in the first principal
component and the second principal component was found to be related to the pain
threshold. Therefore, both were considered
to be related.
The contents are as follows;
The fluctuation of the skin surface current value in the first principal component
was considered to uniformly increase or
decrease all skin surface current values.
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Ryodoraku Medicine and Stimulus Therapy
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Among them, the pain threshold was considered to rise if all skin surface current
values increased. Conversely, if all skinsurface current values decreased, the pain
threshold was considered to decrease.
In other words, it was thought thatwhen all skin surface current values increased, the pain sensation became insensitive, and when all skin surface current
values decreased, the pain sensation became hypersensitive.
In the second principal component, it
was thought that the fluctuation of skinsurface current value increased or decreased against each other in the upperand lower limbs. Among them, it wasthought that the pain threshold increased,
particularly when the skin surface current
values of H4 (SI: small intestine), H5 (TE:triple energizer) and H6 (LI: large intestine) in the upper limbs increased and theskin surface current values of F2 (LR: liver)and F3 (KI: kidney) in the lower limbs decreased.
In other words, it was thought that thepain sensation becomes insensitive or hypersensitive by increasing or decreasing
the skin surface current values on thedorsal side of the upper limbs and the inner side of the lower limbs in opposition toeach other.
The fluctuation of skin surface current
value in the third principal component was
not related to the pain threshold. Therefore, it was thought that there was no relationship between the two measured values.
② Conjecture of pain sensibility by Ryodoraku "i.e.,Meridian" measurement (skinsurface current).
The fluctuation of skin surface current
value in the first principal component was
not found to be related to the pain threshold. Therefore, it was thought that there
was no relationship between the two
measured values.
In the second principal component, it
was thought that the fluctuation of skinsurface current value increased or decreased against each other in the upperand lower limbs. This change in skin surface current was considered to be related
to the pain threshold. Among them, it wasthought that the pain threshold increased,
especially when the skin surface current
value of the upper limbs increased and theskin surface current value of the lower
limbs decreased.
In other words, when the skin surface
current value of the upper limbs increases
and the skin surface current value of thelower limbs decreases, the pain sensation
becomes insensitive, Conversely, when theskin surface current value of the upper
limb decreases and the skin surface current value of the lower limb increases, thepain sensation becomes hypersensitive.
The fluctuation of skin surface current
value in the third principal component was
not related to the pain threshold. Therefore, it was thought that there was no relationship between the two measured values.
③ Relation with Animal Limbs Skin Surface
Current and Pain Threshold.
The fluctuation of skin surface current
value in the first principal component was
not related to the pain threshold. Therefore, it was thought that there was no relationship between the two measured values.
The fluctuation of skin surface current
value in the second principal component
was considered to be contradictory increase or decrease of skin surface current
value of fore and hind limbs. In addition, it
was thought that such fluctuation of skinsurface current was related to pain
threshold. Among them, it was thoughtthat the pain threshold decreased, particularly when the skin surface current valueof the forelimb decreased and the skinsurface current value of the hind limb increased.
In other words, when the skin surface
current value of the forelimb decrease andthe skin surface current value of the hindlimb increases, the pain sensation becomes
hypersensitive, Conversely, when the skinsurface current value of the forelimbs increase and the skin surface current valueof the hind limbs decrease, the pain sensation was thought to be insensitive.
The fluctuation of skin surface current
value in the third principal component was
not related to the pain threshold. There14

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Ryodoraku Medicine and Stimulus Therapy
Vol.2: 1 - 17 ,2019

fore, it was thought that there was no relationship between the two measured values.
The following can be considered by integrating the consideration of each of the ①, ②
and ③ experiments into one. :First, it is considered that the skin surface
current value at each measurement site is aprincipal component (in other words, a factor)
that fluctuates in a direction in which all increase and decrease uniformly. And, this factor is considered as a phenomenon in which
general physical function (activity) is reflected in skin surface current values.
In general, one of the physiological functions of the body considered in this phenomenon is sweat gland activity 21). Furthermore,this activity may be related to external environment such as room (outdoor) temperatureand humidity (atmospheric pressure), andfactors such as age and gender.
In the ① experiment, a relationship isfound between this factor and the pain
threshold. From this relationship, it isthought that pain sensitivity is reduced if all
skin current is high after needle stimulation.
The phenomenon is suggested that the sensitivity of pain is suppressed by the influence ofautonomic nervous function, particularly
sympathetic nerve excitation.
Clinically, patients with "neurosis" aremore sensitive to pain. This experience has
been recognized by many physicians who
have experienced pain treatment 22), 23), 24). Dr.
Imai has provided important suggestions fordiagnosis using the Ryodoraku charting system, through many years of clinical researchusing Ryodoraku therapy. According to it, in
all Ryodoraku measurement (current value =μA), when H system is low (i.e., electrical resistance = large) and F system is high (i.e.,electrical resistance = small), it is pointed outthat it is in a neurosis tendency Fig. 4-1-2), 25).
This point is very interesting in this study.
Unfortunately, however, the variability anddirection of variation of skin surface currents
do not always coincide with the magnitude of
the actual measurements. In addition, the"type" that appears on the chart for Ryodoraku for which the skin surface current value
is plotted does not always match. The reason
is that the eigenvector value and its vector
direction (positive value / negative value) only

indicate the degree to which the skin surface
current increases or decreases, and its direction, A certain correlation is not recognized
between skin surface current values obtainedby actual measurement and analysis resultsof principal component analysis.
But on the other hand, we can not deny thepossibility that they match. From this, theanswer will be found in future research.

Fig.4-1-2 Ryodoraku patternt

In diagnosis with the dedicated chart of Ryodoraku therapy,
the position of the current value plotted on the chart isregarded as important regardless of the current value. Thisis called "Ryodoraku pattern". Generally, the most frequent
pattern has a high H-system current value and a low
F-system current value, which is called a "general type". It
is found in patients with "autonomic imbalance".
In this experiment, it is a pattern in which the current
values of the H system and the F system are reversed, andthis is called "neurose type" because it is found in patientswith "neurosis".

In our previous studies, we found the relationship between Ryodoraku's pattern of"neurosis" tendency and pain threshold, suggesting that this Ryodoraku pattern could be
an objective indicator of "pain sensitivity".
Furthermore, in the ③ experiment, thisphenomenon also appeared in rat skin surface
current values with a current pattern similar
to the tendency of human neurosis. That is,when the forelimbs were low (electrical resistance = large) and the hindlimbs were high(electrical resistance = small), a decrease inpain threshold was observed. This suggeststhat this current pattern is a phenomenoncommon to humans and animals (rats), and it
is again suggested that it may be an objective
indicator of "pain sensitivity". Therefore, it issuggested that the pain sensitivity and thefluctuation of the hand and foot (extremity)skin surface current are biologically relevant
phenomena.
Summarizing the results, Ryodoraku
measurement analyzed using principal com15

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Ryodoraku Medicine and Stimulus Therapy
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ponent analysis is not only applied to diseasediagnosis, but it can also be an index for
grasping the sensitivity to stimulation before
treatment. In addition, it is suggested thatmeasurement before and after stimulation(treatment) is useful for the evaluation oftreatment effect, and objective evaluation of
non-noxious or non-stimulatory "pain".

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