• Journal of Biomedical Engineering Research
• /
• v.30 no.4
• /
• pp.347-354
• /
• 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
• /
• v.13 no.6
• /
• pp.443-448
• /
• 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.

• Journal of Power System Engineering
• /
• v.14 no.4
• /
• pp.29-36
• /
• 2010

This study was performed with 5 subjects and used three kinds of music and vibroacoustic stimuli wave based upon each kinds of music. Executing music stimulation, vibro tactile and acoustic wave stimulation to human body were performed. Then measured brain waves were analyzed under each condition including before stimulation, stimulation 1, and stimulation 2. Effects by stimulation results could be studied with experiments and summarized results are followings. 1. It may be concluded that effects on brain waves by music and vibroacoustic stimulation might differ under different situations such as stimulation types with vibroacoustic equipment, human body and mental conditions when measuring, etc.. 2. During stimuli by using music A, B, and C, the effect of $\alpha$ wave, $\beta$ wave, and SMR wave power values show same tendency to the subject c but music C had very different tendency during vibroacoustic stimuli. 3. During vibroacoustic stimuli by applying the signals of music C, because SMR wave power value was continually increased with consistency comparing to Bst, this can be estimated that an application of inducing mind concentration condition would be possible under relaxed body and mind conditions. 4. To secure data significance, all measured data need to be tested statistically whether data would be interrelated or not.

• Korean Journal of Veterinary Research
• /
• v.38 no.3
• /
• pp.614-628
• /
• 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.

• The Journal of the Korea Contents Association
• /
• v.11 no.10
• /
• pp.286-292
• /
• 2011

This study investigated the degree of fracture healing using cathode stimulation of microcurrent, cathode and anode stimulation of High Voltage Pulsed Galvanic Current (HVPGC). Measures were performed by X-ray test and Hematoxylin-Eosin stain and Masson's trichrome stain and osteocalcin-positive immunoreactivity. In the measure of X-ray, microcurrent stimulation group revealed more rapid recovery than the groups of HVPGC's cathode and anode stimulation in bone union degrees. Microcurrent group showed significant difference statistically (p<0.05). However, the groups of HVPGC's cathode and anode stimulation didn't show significant difference statistically(p>0.05). In the histologic examination with Hematoxylin-Eosin and Masson's trichrome, microcurrent stimulation group was observed more proliferation of irregular woven bones than the groups of HVPGC's cathode and anode stimulation. Osteocalcin-positive immunoreactivity was observed more osteoblast, osteocyte, osteoclast, bone matrix than the groups of HVPGC's cathode and anode stimulation. Microcurrent stimulation can be considered an effective way during healing of fresh fracture and it can show more effective method than HVPGC's cathode and anode stimulation in the fracture healing.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.8 no.2
• /
• pp.19-24
• /
• 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.

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.11 no.1
• /
• pp.31-38
• /
• 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.

• Journal of Korean Physical Therapy Science
• /
• v.26 no.2
• /
• pp.24-31
• /
• 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.

• Journal of International Academy of Physical Therapy Research
• /
• v.10 no.1
• /
• pp.1700-1705
• /
• 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.

• Journal of the Korean Society of Physical Medicine
• /
• v.13 no.4
• /
• pp.95-103
• /
• 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.