• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.399-402
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• 2002

In this study, we constructed a four-channel impedance measurement system including a two-channel goniometer to analyze human arm movement. Impedances and joint angles were simultaneously measured for wrist and elbow movements. As the impedance changes resulting from wrist and elbow movements depended heavily on electrode placement, we determined the optimal electrode configurations for those movements by searching for high correlation coefficients, large impedance changes, and minimum interferences in ten subjects (age: 29+6). Our optimal electrode configurations showed very strong relationships between the wrist joint angle and forearm impedance (correlation coefficient = 0.95+0.04), and between the elbow joint angle and upper arm impedance (correlation coefficient = -0.98+0.02). Although the measured impedances changes of the wrist (1.1+1.5 ohm) and elbow (-5.0+2.9 ohm) varied among individuals, the reproducibilities of wrist and elbow impedance changes of five subjects were 5.8+1.8 % and 4.6+1.4 % for the optimal electrode pairs, respectively. We propose that this optimal electrode configuration would be useful for future studies involving the measurement of accurate arm movements by impedance method.

• Journal of Biomedical Engineering Research
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• v.20 no.3
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• pp.323-329
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• 1999

This paper proposed a method for the cancellation of the moving artifact which was produced during the detection of drowsiness usmg electrodermal activity signal. Two types of wrist electrode were developed to overcome the defect of the steering wheel type electrode which couldn't eliminate the moving artifacts due to driver's movements. Wrist type electrode II which has been modified from electrode type I was most effective for eliminating movmg artifacts compared to wheel type electrode and wrisL type electrode 1. The decIsion criteria(if IRI$\leq$10 and 1.1$\leq$dNz) for detecting moving artifact was determined from the virtual driving experiments. An algorithm which substituted past value of Nz for the current value of Nz whenever an EDA signal satisfied the criteria was developed. The experimental resulls of virtual driving and road test showed that the proposed algorithm had been successfully removed the most of the error due to the moving artifact Therefore, the developed system which use electrode type II and the algorithm might be less influenced by moving artifacts and could measure an accurate arousal state.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.151-156
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• 2004

The purpose of this study was to develop EMG triggered FES system for restoration of upper extremity function in chronic hemiplegic patients and to identify the optimal location of electrode application for the EMG triggered FES system which produces effective muscle contraction and detects EMG activity for extension in the wrist and finger joints. The stimulus system was composed of EMG measuring component, constant current component and the program for muscle contraction by EMG triggered FES and passive FES. Parameter of electrical stimulation was 35 ㎐ in frequency, 150 ${\mu}\textrm{s}$ in pulse width and symmetric bi-phasic wave. In 15 hemiplegic patients, EMG triggered FES was applied to the proximal half of forearm which was divided into 12 areas. The most sensitive area for measuring EMG activities during extension of the wrist and fingers was area 4, 5 and the optimal location of electrical stimulation for producing extension of the wrist and fingers was area 4, 5, 7, 8. These results suggest that the area 4 and 5 was considered as the most optimal location of electrode application for measuring EMG activities as well as producing extension of the wrist and fingers by EMG triggered FES system.

• The Journal of Korean Physical Therapy
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• v.6 no.1
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• pp.85-93
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• 1994

The purposes of this study were 1) to examine the effects of microcurrent electrical neuromuscular stimulation 2) to compare surface electrode with needle electrode at somatic acupuncture points on experimental pain threshold measured at the distal end of the radius 3) to determine the changes in effect over time. A total of sixty healthy adult male and female subjects were assigned randomly to one of two experimental group or to a control group. Group 1(n=20) received MENS(Microcurrent Electrical Neuromuscular Stimulation) with surface electrode. Group 2(n=20) received HENS with needle electrode. Group 3(n=20) received no MENS. It measured experimental pain threshold at the wrist on pretreatment, 0 min after treatment. 15 min after treatment, 30 min after treatment in two experimental group. The results were as follows: 1. Experimental pain thresholds were higher in males than females(P<0.01). 2. Only the experimental group exhibited a significant increased in pain threshold after MENS treatment(P<0.05). 3. Surface electrode group increased significant pain threshold 0 min, 15 min after treatment, but greatly decrease 30 min after treatment. 4. Needle electrode group increased significant pain threshold 0 min, 15 min after treatment, but decrease 30 min after treatment. The results suggest that MENS applied to appropriate somatic acupuncture point can increase pain threshold. Further research is needed to assess the effects of greatly variety intensity of MENS of pain sufferes.

• Journal of Sensor Science and Technology
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• v.18 no.5
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• pp.359-364
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• 2009

This paper presents flexible electrocardiography(ECG) sensors using micro electro mechanical systems(MEMS) and flexible printed circuit(FPC) technology. By using FPC technology, ECG sensors which consisted of an outer hook-shaped electrode and an inner circular-shaped electrode were fabricated on the polyimide substrate. Thereafter, the bipolar ECG sensor was miniaturized using MEMS technology. The ECG measurement capability was examined by attaching the sensor to the human chest and wrist. Performance of the proposed sensors was then compared with ECG measured by commercial Ag/AgCl electrodes. It was verified that ECG could be measured using proposed sensors at only single body.

• Journal of Acupuncture Research
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• v.21 no.6
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• pp.249-257
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• 2004

Objective : Radial nerve palsy is characterized by palsy or paralysis of extensors of the wrist and digits, as well as the forearm supinators. Very proximal lesions also may affect the triceps. Numbness occurs on the dorsoradial aspect of the hand and the dorsal aspect of the radial 3 and 1/2 digits. We observed 7 patients with radial nerve palsy, the results are as follows. Methods & Results : All patients were treated by the same method and treatment was performed by acupuncture and Neuromuscular Electrical Stimulation. the electrode were placed unilaterally on the motor points of forearm. As the result, symptoms are improved remarkably. Conclusions : Patients were treated for 5.4 weeks, 14.7 times(average). The grade was that 6 cases were good and 1 case was excellent.

• Journal of Biomedical Engineering Research
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• v.23 no.5
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• pp.413-418
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• 2002

The purpose of this study was to design a single frequency BIA(Bioelectrical Impedance Analyzer) which can measure body impedance when patient is sitting on the toilet and to develope a prediction equation for designed BIA. For the purpose of this study, we acquired body impedances with designed BIA from 181 subjects composed of healthy Korean by attaching electrodes to suitable positions(wrist and thigh) for toilet measurement. We computed an appropriate FFM(Fat Free Mass) for Korean using modified-Siri equation to the same subjects instead of Siri equation which nay cause accuracy problems in hydrodensitometry when it applied to Korean. We used this FFM as reference value and developed a Korean FFM prediction equation based on body impedance index, body weight and sex. Correlation coefficient between prediction value and reference value of FFM was extremely high (r = 0.977) and SEE(Standard Error of Estimation) was low 2.47kg.(p<0.05) For comparison between existing electrode-attaching method and our method for toilet measurement, we acquired body impedance with designed BIA from same subjects attaching electrodes on existing positions (wrist and ankle) and made FFM prediction equation for BIA. Correlation coeffient between predicted value and reference value was 0.978 and SEE was 2.43kg(p<0.05). It means that the developed system has not significant differences with existing method. In conclusion bioelectrical impedance analyzer and the FFM prediction equation developed in this paper are evaluated to he adequate to compute FFM of Korean.

• The Journal of Korean Physical Therapy
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• v.6 no.1
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• pp.171-183
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• 1994

Purphose. This present study examines the effect of brief, intense transcutaneous electrical nerve stimulation(BTENS) on sensory nerve conduction, electrical pain threshold, and two-point discrimination measured at the superficial radial nevre distribution in 20 healthy subjects. Subjects. Twenty volunteercs, (10 females and 10 males(age range : 20-38 years : $mean{\pm}SD\;:\;27.00{\pm}5.12$), only subjects without prior traumatological and pathological were eligible to participated in this study. Methods. Nerve conduction were determined for the right superficial radial nerve. Electrical pain threshold were determined for the right wrist ipsilateral to the site of BTENS. Small disc electrodes were attached to the surface of the skin stradding the end of the radius. Square wave electrical pulses were delivered from an isolated stimulator through a constant current device at a frequency of 2 Hz(5 ms pulse width). Two-point discrimination, measured on the sensory distribution of superficial radial nerve. BTENS was delivered using a Max-SD( Medical design co.) portable battery powered stimulator. A cicular Ag/AgCl electrode in contact with hypertonic saline gel was attached to the lateral(radial side) surface of the forearm. Results. No significant effects were observed between stimulation methods in the prestimulation cycle(multi-way ANOVA repeated measures : distal latency ; F1.14=0.332. amplitude ; F 0.80=0.445, pain threshold ; F0.06=0.940.2 point discrimination ; F1.50=0.236). Highly significant effects were observed time with the pretreatment and 6 posttreatment cycles(p<0.01). Mighty significants differences in nerve conduction and pain threshold were found using un multi-way ANOVA repeated measures among stimulation methods for each cycles(p<0.01). Conclusion and Discussion The authors concludes that both nerve conduction and pain threshold changes are associated with therapy (stimulation) level of BTENS.

• Journal of Biomedical Engineering Research
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• v.13 no.2
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• pp.133-140
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• 1992

Bioelectrical Impedance method for measuring human body composition is based upon the principle that the electrical conductivity of the fat-free mass (FFM) is far greater than that of the (at. Deter- mination o( impedance was nlade in 30 healthy and obese men aged $40.9{\pm}14.7$yr (mean${\pm}$SD) and 25 healthy and obese women aged $44.0{\pm}10.2$ yr. A commercial impedance body fat analyzer was used with a four electrode arrangement that introduced a painless constant current(ImA at 50 kHz) into the body. Linear relationships were found between impudence values and FFM(r=-0.786) and between weight and FFM(r=0.837). Signigicant increases in the correlation coefficients were ob served when the predicator Hta/z was regressed against FFM(r=0.912) where Ht Is height and Z Is impedance. A linear regression equation, FFM=0.586(Htf/z) +0.317(Weight) -1.674(r=0.977), was found. The correlation coefficient of % body fat between the impedance and infrared methods was 0.898. These data Indicate that the bioelectrical impedance technique is a reliable and valld approach for the estimation of human body composition. This method Is safe, noninvasivr, prouides rapld measure menu, requires little operator skill and subject cooperation, and Os portable. Finally measurement of percent body fat was made possible using both the regression equation and a developed impedance measuring device which measures impedance between wrist and ankle.

• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.21-27
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• 2022

Flexible pressure sensor was developed using low-cost conductive graphite as printed electronics. Flexible pressure sensors are attracting attention as materials to be used in future industries such as medical, games, and AI. As a result of evaluating various electromechanical properties of the printed electrode for flexible pressure sensors, it showed a constant resistance change rate in a maximum tensile rate of 20%, 30° tension/bending, and a simple pulse test. A more appropriate matrix pattern was designed by simulating the electrodes for which this verification was completed. Utilizing the Serpentine pattern, we utilized a process that allows simultaneous fabrication and encapsulation of the matrix pattern. One side of the printed graphite electrode was O₂ plasma surface treated to increase adhesive strength, rotated 90 times, and two electrodes were made into one through a lamination process. As a result of pasting the matrix pattern prepared in this way to the wrist pulse position of the human body and proceeding with the actual measurement, a constant rate of resistance change was shown regardless of gender.