• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.720-723
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• 2003

Electric stimulation of teeth is used for assessing pulp vitality. Because of very high and wide range of impedance of the enamel, electric pulp testers use high voltage, high output impedance and alternative current source. Most pulp testers use voltage stimulation method and their stimulating threshold levels significantly depend on each individual. Therefore, a constant current stimulator is necessary to minimize the effect of wide variation in enamel thickness. In this study, we constructed a constant current source type of pulp tester with the maximum current of 150 uA.

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.109-116
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• 2009

Purpose: $17\beta$-estradiol is the most active endogenous estrogen, which is related to favorable changes in the plasma lipid profile, to relaxation of the coronary vessels, and to a decrease in platelet aggregation and vascular smooth muscle cell migration. However, although the beneficial effect of estrogens on plasma lipoproteins (ie, lowering low-density lipoprotein and increasing high-density lipoprotein cholesterol) contributes to cardiovascular protection, it does not fully account for the protective effect, particularly in the application of physical therapy, including low frequency electrical stimulation. Methods: The aim of this study was to demonstrate the inhibition of stressors, such as endothelin-1 (ET-1), serotonin (5-hydroxytryptamine, 5-HT), prostaglandin $F2\alpha$ ($PGF2\alpha$), and a protein kinase C (PKC) activator 12-deoxyphorbol 13-isobutyrate (DPB), induced isometric tension by $17\beta$-estradiol in vascular smooth muscle strips, respectively. In addition, the effects of low frequency electrical stimulation at the meridian points (CV-3, -4, Ki-12, SP-6, LR-3, BL-25, -28, -32, -52) on the indirect antihypertensive effect were examined by monitoring the changes in the serum $17\beta$-estradiol concentration in healthy volunteers. Results: Isometric tension analysis showed that the responses of inhibited tension by $17\beta$-estradiol were similar to the same stressors in rat aortic smooth muscle strips. Furthermore, although the continued amplitude modulation (AM) type of electrical stimulation was not increased significantly by electrical stimulation, the current of the frequency modulation (FM) type of low frequency electrical stimulation increased the serum $17\beta$-estradiol concentration in normal volunteers. Conclusion: These results, in part, suggest that $17\beta$-estradiol has the capacity to supress stressor-induced muscle tension, and electrical stimulation, particularly current of the FM type, has a modulatory effect on the sex steroid hormones, particularly $17\beta$-estradiol, in healthy volunteers.

• Journal of Biomedical Engineering Research
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• v.23 no.4
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• pp.287-293
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• 2002

For non-contact nerve stimulations using time varying magnetic field, high amplitude current pulses have to be applied to a magnetic nerve stimulation coil. To increase the magnetic stimulation frequency we have to increase both power supply capacity and cooling capacity of the magnetic nerve stimulator. To alleviate these problems. we propose a new magnetic nerve stimulation coil design methods. Utilizing magnetic mirror effect of a ferro-magnetic plate attached to a magnetic stimulation coil. we have improved efficiency of the stimulation coil. We have analyzed magnetic mirror effect for various kinds of stimulation coils using the finite element method, and we present experimental results obtained with several kinds of stimulation coils.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.6
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• pp.1505-1510
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• 2010

Response to nerve stimulation platform for implementing measures to detect finger movement has been functioning as an important factor. The finger movement of the muscle response to nerve stimulation and sensing Actuator for the H/W development is needed. In addition, a low power embedded CPU based on the top was used. H/W configuration portion of the isolation power, constant current control, High impedance INA, amplifier parts, and the stimulus mode and the Micro-control the status of current, AD converter Low Data obtained through the processing system is implemented.

• The Journal of Korean Physical Therapy
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• v.16 no.3
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• pp.22-31
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• 2004

The purpose of this study was to demonstrate the effects of silver spike point (SSP) low frequency electrical stimulation on plasma ${\beta}-endorphin$ activities measured by radio- immunoassay from normal volunteer and the effects of ${\beta}-endorphin$ on 5-hydroxytryptamine (5-HT, serotonin)-induced contraction investigated by isometric tension methode in rats. The current of 3 Hz continue type, but not 100 Hz continue type, of SSP low frequency electrical stimulation significantly increased in plasma ${\beta}-endorphin$ from normal volunteer. The endothelial cell-dependent 5-HT-induced contractions were inhibited by ${\beta}-endorphin$ $1{\mu}M$. These results suggest that the ${\beta}-endorphin$ regulates nociceptive-like substance, such as 5-HT, in part and that the SSP low frequency electrical stimulation, specifically current of low frequency of 3 Hz continue type, significantly increases plasma ${\beta}-endorphin$ from normal volunteer.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.87-97
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• 2021

Purpose : The purpose of this meta-analysis was to evaluate the effects of transcranial direct current stimulation on the lower extremity function of stroke patients. Methods : Domestic data were gathered from studies that conducted clinical trials associated with transcranial direct current stimulation and its impact on lower extremity function of stroke patients. A total of 592 studies published between 2012 and 2020 were identified, with 7 studies satisfying the inclusion data. The studies consisted of patient, intervention, comparison, and outcome (PICO) data. The search outcomes were items associated with muscle activity, balance, muscle strength and walking ability. Cochrane risk of bias (ROB) was used to evaluate the quality of 3 randomized control trials. The quality of 4 non-randomized control trials was evaluated using risk of bias assessment tool for non-randomized studies (RoBANS). Effect sizes in this study were computed as the corrected standard mean difference (SMD). A random-effect model was used to analyze the effect size because of the high heterogeneity among the studies. Egger's regression and 'trim-and-fill' tests were carried out to analyze the publishing bias. Results : The following factors had a large total effect size (Hedges's g=2.10, 95 %CI=1.54~2.66) involving transcranial direct current stimulation on stroke patients: muscle activity (Hedges's g=2.38, 95 %CI=1.08~3.68), balance (Hedges's g4=2.41, 95 %CI=1.33~3.60), walking ability (Hedges's g=1.54, 95 %CI=0.49~2.59), and muscle strength (Hedges's g=2.45, 95 % CI: 0.85~4.05). Egger's regression test showed that the publishing bias had statistically significant differences but 'trim-and-fill' test showed that there was still statistical difference. Conclusion : This study provides evidence for the effectiveness of transcranial direct current stimulation on the lower extremity in terms of muscle activity, balance, walking ability, and muscle strength in stroke patients. However, due to the low quality of studies and high heterogeneity factors, the results of our study should be interpreted cautiously.

• Current Optics and Photonics
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• v.3 no.1
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• pp.1-7
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• 2019

Optical stimulation provides a promising alternative to electrical stimulation to selectively modulate tissue. However, developing noninvasive techniques to directly stimulate excitable tissue without introducing genetic modifications and minimizing cellular stress remains an ongoing challenge. Infrared (IR) light has been used to achieve optical pacing for electrophysiological studies in embryonic quail and mammalian hearts. Here, we demonstrate optical stimulation and pacing of the embryonic chicken heart using a pulsed infrared thulium laser with a wavelength of 1927 nm. By recording stereomicroscope outputs and quantifying heart rates and movements through video processing, we found that heart rate increases instantly following irradiation with a large spot size and high radiant exposure. Targeting the atrium using a smaller spot size and lower radiant exposure achieved pacing, as the heart rate synchronized with the laser to 2 Hz. This study demonstrates the viability of using the 1927 nm thulium laser for cardiac stimulation and optical pacing, expanding the optical parameters and IR lasers that can be used to modulate cardiac dynamics.

• The Journal of Korean Physical Therapy
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• v.21 no.4
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• pp.65-71
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• 2009

Purpose: Transcranial direct current stimulation (tDCS) is a useful method for modulating the brain activity. This study compared the effect of continuous and interrupted tDCS using the change in the movement related cortical potential. Methods: Thirty healthy participants (male: 18 and female: 12) were assigned randomly to three groups; sham tDCS, continuous tDCS, which the current continuously flowed for 10 minutes, and interrupted tDCS, which the interrupted current flowed for 10 minutes (repetition: 4sec stimulation and 5sec rest) at an intensity of 1mA with anodal polarity. The effect of tDCS on the right primary motor area was measured from the movement related cortical potential (MRCP) before and after the experiment. MRCP consisted of the bereitshaftspotential (BP) and negative slope potential (NS) at Cz and C4. Results: Continuous and interrupted tDCS showed a significant difference in the changes in the BP, NS at Cz and C4 compared to the sham tDCS. However, there was no significant difference between the continuous tDCS and interrupted tDCS. Conclusion: The change in cortical activity by continuous and interrupted tDCS results from an improvement in the MRCP. An interrupted tDCS may be a safe and useful modality for stimulating the cortical region.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.2029-2037
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• 2015

The purpose of this study was to investigate the effect the interferential current (IFC) stimulation level according to autonomic nerve system (ANS) of healthy adults. IFC measured with adhesive 2-pole electrodes pad on T1~T4 spinal cord segment level that electrode stimulation of 20 min after. A total of 45 healthy adults participated in the study, who were randomly divided into three groups: 15 of sensory level stimulus group (100 bps, 10~12 mA), 15 of exercise level stimulus group (5 bps, 45~50 mA), 15 of noxious level stimulus group (100 bps, 80~90 mA). Measured items were sympathetic activity and parasympathetic activity. In order to identify the changes in measurement variables before electrode stimulation and after and 30 min stimulation. The comparison of sympathetic and parasympathetic activity in each group revealed that they was changes of after vs 30 min in after electrical stimulation time(p<.05).

• Journal of Korean Physical Therapy Science
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• v.10 no.1
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• pp.158-169
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• 2003

The present study examined that in vivo test is investigated in sham-operated(control group) and aldosterone-analogue deoxycorticosterone acetate (DOCA)-salt hypertensive animals(experimental group) and that the antihypertensive effect was induced by silver spike point(SSP) low frequency electrical stimulation at meridian points(CV-3, -4, Ki-12, SP-6, LR-3, BL-25, -28, -32, -52), specifically, such as diuretic action in 24 hour urine analysis from normal volunteer. The $Na^+$ and $Ca^{2+}$ ions were significantly increased in aldosterone-analogue DOCA-salt hypertensive rats than that in sham-operated rats. However, the $K^+$ ions were significantly decreased in aldosterone-analogue DOCA-salt hypertensive rats than that in sham-operated rats. The current of 1 Hz continue type of SSP low frequency electrical stimulation significantly increased in excretion of urine $Na^+$ and $K^+$ ions from normal volunteer. However, the excretion of $Ca^{2+}$ ion were significantly decreased by SSP electrical stimulation in volunteer. These results suggest that the development of aldosterone analogue-DOCA-salt hypertension is associated with changed $Na^+$, $K^+$ and $Ca^{2+}$ ions of urine. which directly affects blood pressure. Therefore, the hypertension is a risk factor on cardiovascular disease. Moreover, These results demonstrate that the SSP low frequency electrical stimulation, especially current of 1 Hz continue type, significantly regulates $Na^+$, $Ca^{2+}$ and $K^+$ ions from volunteer. Therefore, the SSP low frequency electrical stimulation is a good regulator through a diuretic action of aldosterone-induced hypertension.