• 대한의용생체공학회:의공학회지
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• 제30권4호
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• pp.347-354
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• 2009

For the reliable transmission of meaningful visual information using prosthetic electrical stimulation, it is required to develop an effective stimulation strategy for the generation of electrical pulse trains based on input visual information. The characteristics of neuronal activities of retinal ganglion cells (RGCs) evoked by electrical stimulation should be understood for this purpose. In this study, for the development of an optimal stimulation strategy for visual prosthesis, we analyzed the neuronal responses of RGCs in rd1 mouse, photoreceptor-degenerated retina of animal model of retinal diseases (retinitis pigmentosa). Based on the in-vitro model of epiretinal prosthesis which consists of planar multielectrode array (MEA) and retinal patch, we recorded and analyzed multiunit RGC activities evoked by amplitude-modulated electrical pulse trains. Two modes of responses were observed. Short-latency responses occurring at 3 ms after the stimulation were estimated to be from direct stimulation of RGCs. Long-latency responses were also observed mainly at 2 - 100 ms after stimulation and showed rhythmic firing with same frequency as the oscillatory background field potential. The long-latency responses could be modulated by pulse amplitude and duration. From the results, we expect that optimal stimulation conditions such as pulse amplitude and pulse duration can be determined for the successful transmission of visual information by electrical stimulation.

• The Korean Journal of Physiology and Pharmacology
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• 제13권6호
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• pp.443-448
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• 2009

For successful visual perception by visual prosthesis using electrical stimulation, it is essential to develop an effective stimulation strategy based on understanding of retinal ganglion cell (RGC) responses to electrical stimulation. We studied RGC responses to repetitive electrical stimulation pulses to develop a stimulation strategy using stimulation pulse frequency modulation. Retinal patches of photoreceptor-degenerated retinas from rd1 mice were attached to a planar multi-electrode array (MEA) and RGC spike trains responding to electrical stimulation pulse trains with various pulse frequencies were observed. RGC responses were strongly dependent on inter-pulse interval when it was varied from 500 to 10 ms. Although the evoked spikes were suppressed with increasing pulse rate, the number of evoked spikes were >60% of the maximal responses when the inter-pulse intervals exceeded 100 ms. Based on this, we investigated the modulation of evoked RGC firing rates while increasing the pulse frequency from 1 to 10 pulses per second (or Hz) to deduce the optimal pulse frequency range for modulation of RGC response strength. RGC response strength monotonically and linearly increased within the stimulation frequency of 1~9 Hz. The results suggest that the evoked neural activities of RGCs in degenerated retina can be reliably controlled by pulse frequency modulation, and may be used as a stimulation strategy for visual neural prosthesis.

• 동력기계공학회지
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• 제14권4호
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• pp.29-36
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• 2010

인체에 음향진동장치에 의하여 자극을 가하였을 경우 영향을 고찰한다. 5명의 건강한 남자 대학생을 대상으로 하여, 3가지 형태의 음악을 음향과 진동자극의 신호원으로 사용해서 실험을 행하였다. 모든 피험자에 대하여, 자극 전, 음악자극, 진동자극, 자극 후로 나누어 뇌파를 측정하였다. 실험의 모든 피험자의 측정 데이터의 t-검정을 수행하여 유의성이 있는 데이터에 한하여 뇌파를 고찰하였다. 결과로서, 음악과 음향파와 진동자극이 뇌파에 미치는 영향은 음향진동장치에 따른 진동자극 형태, 피험자의 몸과 정신 상태에 따라 현저하게 달라질 수 있다는 것을 알 수 있다. 그리고 적절한 음악과 음향진동장치를 사용하여 특정의 뇌파 상태를 유도 할 수 있음을 확인하였다.

• 대한수의학회지
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• 제38권3호
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• pp.614-628
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• 1998

The effects of electroacupuncture(EA) on blood concentration of endocrine substances were investigated in 6 horses. Three acupuncture points ; Guan Yuan Shu(BL-26), Wei Shu(BL-21) and Da Chang Shu(BL-25) were stimulated for 20 minutes by EA at separate occasions under varying condition ; 2V-1Hz, 2V-5Hz, 2V-30Hz, 4V-1Hz, 4V-5Hz and 4V-30Hz. Plasma levels of adrenocorticotropic hormone(ACTH), ${\beta}$-endorphin, epinephrine, norepinephrine and serum levels of gastrin were analysed. Blood samplings were carried out before, 0, 20 and 40 minutes after the EA stimulation. The serum gastrin levels were increased by 2V-5Hz stimulation on the Wei Shu. Plasma ACTH levels were decreased by 2V-1Hz stimulation on the Wei Shu, but largely increased by 4V-30Hz stimulation on the Guan Yuan Shu. Plasma ${\beta}$-endorphin levels were slightly increased or decreased by 2V-1Hz stimulation, but largely increased by 4V-30Hz stimulation on the Guan Yuan Shu. Plasma levels of epinephrine and norepinephrine were not so much changed by 2V-1Hz or 5Hz stimulation, but tended to increase by 4V-30Hz stimulation on Guan Yuan Shu. These results suggest that the low voltage-low frequence EA stimulation increased blood concentration of gastrin, but decreased ACTH, ${\beta}$-endorphin, epinephrine and norepinephrine, whereas high voltage-high frequence EA stimulation induced opposite results. Accordingly, there appears to be a close relationship between the changes of gastrointestinal motility and the changes of blood concentration of endocrine substances by EA stimulation.

• 한국콘텐츠학회논문지
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• 제11권10호
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• pp.286-292
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• 2011

본 연구는 토끼골절모델에 미세전류자극(직류, 음극), 고전압 맥동직류 음극과 양극을 이용해 골절치유정도를 살펴보았다. 방사선 검사에 의한 육안 계측은 미세전류자극군이 고전압 맥동직류의 음극과 양극 통전군보다 골절치유척도 점수에서 통계학적으로 유의한 차이를 보였으나(p<0.05), 고전압 맥동직류 음극군과 양극군 사이에는 유의한 차이가 없었다(p>0.05). Hematoxylin-Eosin 염색과 Masson's trichrome 염색을 통한 병리조직표본 차이는 미세전류자극군에서 무층골의 증식이 다른 두 실험군보다 더 활발하게 관찰되었으며 연골내골화 과정도 다른 두 실험군에 비해 더 빠른 것으로 관찰되었다. Osteocalcin 면역조직화학 염색은 미세전류자극군이 골모세포, 골세포, 파골세포 및 골기질 내에서 면역양성반응이 다른 두 실험군보다 더 명확히 관찰되었다.

• 대한임상전기생리학회지
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• 제8권2호
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• pp.19-24
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• 2010

Purpose : This study aims to examine the influences of galvanic vestibular stimulation on autonomic reaction of normal adults. Methods : Participants in this research totaled 28 (14 men and 14 women). Galvanic vestibular stimulation was conducted with a binaural electrode configuration for 60 sec. Galvanic vestibular stimulation measurements were conducted with the subjects in a prone position. Measured items included skin conductance, blood flow, pulse rate, and respiratory rate. Measurements were repeated for a total of five times, before application, during application, after application, 5 minutes after application and 10 minutes after application. Results : Skin conductance reaction showed statistically significant differences in changes depending on time after galvanic vestibular stimulation and there were statistically differences in changes of blood flow, pulse rate and respiratory rate after galvanic vestibular stimulation. Conclusion : Blood flow, pulse rate and respiratory rate of autonomic reactions were not influenced by galvanic vestibular stimulation, but skin conductance reaction was influenced by it and it was found that it was reduced during and after stimulation rather than before stimulation. Consequently, it was considered that galvanic vestibular stimulation affected the autonomic reaction.

• 대한임상전기생리학회지
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• 제11권1호
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• pp.31-38
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• 2013

Purpose : This study was to identify the effect of cognitive reaction following inactive electrode placement when applying anodal transcranial direct current stimulation over the primary motor cortex. Methods : For this study a total of 28 stroke patients participated. Before applying transcranial direct current stimulation, cognitive reaction was measured (P300 of event related potential, cognitive reaction time), and subjects were randomly assigned to two group. Transcranial direct current stimulation was applied to the scalp with an intensity of $0.04mA/cm^2$ for 15 minutes. All subjects were given an anode transcranial direct current stimulation over the primary motor area and inactive electrodes over the deltoid muscle (group I) and supra-orbital area (group II). Cognitive reactions were measured after applying transcranial direct current stimulation. Results : For this study a total of 28 stroke patients participated. Before applying transcranial direct current stimulation, cognitive reaction was measured (P300 of event related potential, cognitive reaction time), and subjects were randomly assigned to two group. Transcranial direct current stimulation was applied to the scalp with an intensity of $0.04mA/cm^2$ for 15 minutes. All subjects were given an anode transcranial direct current stimulation over the primary motor area and inactive electrodes over the deltoid muscle (group I) and supra-orbital area (group II). Cognitive reactions were measured after applying transcranial direct current stimulation. Conclusion : Thus transcranial direct current stimulation on the primary motor area may help cognitive reaction regardless of inactive electrode placement.

• 대한물리치료과학회지
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• 제26권2호
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• pp.24-31
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• 2019

Purpose: The purpose of this study was to investigate the effect of olfactory stimulation on the balance ability of the elderly. Design: Randomized controlled trial. Methods: A total of 20 subjects were randomly assigned to the olfactory stimulation group (2 males and 8 females) and deception olfactory stimulation group (3 males and 7 females). Subjects were subjected to 30 second 3 times olfactory stimulation and deception olfactory stimulation, and the assessment measured pre and post postural distance and postural speed. Results: In the elderly, the olfactory stimulation group was significantly improved the postural distance and postural speed in the eyes closed state than the deception stimulation group (p<.05). Conclusion: As the information is provided through the olfactory stimulation, the postural distance and postural speed are significantly improved. therefore, it is expected that the olfactory stimulation in the elderly will be an effective intervention method to prevent fall.

• 국제물리치료학회지
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• 제10권1호
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• pp.1700-1705
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• 2019

Background: Mild cognitive impairment (MCI) is also called as aging related memory damage. Decreased cognitive function due to aging is known to be associated with the frontal lobe. Alpha wave is generated in the dominance in the frontal lobe or a wide range of regions in the brain, it should be doubted that the brain function might be degraded. Objective: To determine the effect of sensory stimulation type on learning and brain activity pattern of elderly persons with MCI. Design: Randomized Controlled Trial (single blind) Methods: Twenty elderly persons aged more than 65 with MCI were randonmized to simultaneous visual/auditory stimulation group (SVASG) and or auditory stimulation group (ASG). Ten peoples were assigned to each group and lectroencephalogram test was performed to individuals. In the electroencephalogram test, electroencephalography of prior to sensory stimulation, and during sensory stimulation were measured to compare brain activity pattern according to the study groups and measurement period. Results: The relative alpha power due to a sensory stimulation type showed that the SVASG significantly decreased in the left frontal lobe and the left parietal lobe statistically compared to those of the ASG while sensory stimulation was given (p<.05). The relative beta power due to a sensory stimulation type showed that the SVASG significantly increased in the left and right frontal lobes, the left and right parietal lobes, and the left temporal lobe statistically compared to those of the ASG while sensory stimulation was given (p<.05). Conclusions: Electroencephalographic analysis showed that the type of sensory stimulation can affect the brain activity pattern. However, the effects were not studied that which brain activity pattern help to improved cognitive function of elderly persons with mild cognitive impairment.

• 대한물리의학회지
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• 제13권4호
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• pp.95-103
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• 2018

PURPOSE: The present study was conducted to investigate the effects of functional electrical stimulation gait training with rhythmic auditory stimulation on balance and gait ability in stroke patients. METHODS: In this blinded randomized controlled study, 26 stroke patients were assigned to either experimental group (n=13) consisting of 30 min of gait training 5 days per week for 4 weeks while performing functional electrical stimulation gait training with rhythmic auditory simulation, or a control group (n=13) performing the same gait training program, also consisting of 30 minutes 5 days a week and lasting for 4 weeks, but without functional electrical stimulation and rhythmic auditory stimulation. At baseline and after the 4 week intervention, balance was measured using the timed up and go test (TUG). Gait velocity was measured using the 10-meter walk test (10 MWT) and gait ability was assessed using the functional gait assessment (FGA). RESULTS: After the intervention, the experimental group showed statistically significant differences in gait velocity and ability (10 MWT, FGA) (p<.05). Between-group differences were statistically significant in gait velocity and ability (10 MWT, FGA) (p<.05). CONCLUSION: The findings suggest that functional electrical stimulation gait training with a rhythmic auditory stimulation gait training program may help improve gait ability in stroke patients.