Hemodynamic Response of Anodal Transcranial Direct Current Stimulation Over the Cerebellar Hemisphere in Healthy Subjects

Study Overview
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Brief Summary
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Upper extremity motor impairment is one of the major sequelae of stroke, resulting in limitation of activities of daily livings. Noninvasive neuromodulation is one of the therapies for motor recovery, which includes transcranial magnetic stimulation and transcranial direct current stimulation(tDCS). Anodal tDCS increases excitability and cathodal tDCS decreases excitability of neurons. In systematic reviews, tDCS applied over primary motor cortex showed positive results on motor learning and improvements of hand fine motors. Recently, there has been trials of tDCS over cerebellum, considering the connectivity of primary motor cortex and cerebellum in motor controls. However, the results of these trials are yet contradictory, and the study using the functional near infrared spectroscopy to prove the effects of tDCS over distant area is lacking. Therefore, in this study, we used functional near infrared spectroscopy (fNIRS) to observe the hemodynamic change of primary motor cortex when applying tDCS over cerebellum ascertain their connectivity. In this crossover design, participants are randomly allocated to sham tDCS-washout period-anodal tDCS group or anodal tDCS- washout period- sham tDCS group. The recording of fNIRS starts 3 minutes before the tDCS stimulation and continues throughout 20 minutes of stimulation, until 30 minutes after the stimulation cessation. After 7 days of washout period, second recording is done as the same protocol. Outcome measures are the changes of concentration of deoxyhemoglobin [deoxy-Hb] and oxyhemoglobin [oxy-Hb].

Official Title
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Hemodynamic Response of Anodal Transcranial Direct Current Stimulation (tDCS) Over the Cerebellar Hemisphere in Healthy Subjects: A Pilot Trial

Conditions
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Stroke, Transcranial Direct Current Stimulation, Functional Near Infrared Spectroscopy

Intervention / Treatment
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* Device: tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age: 19 years or older No known brain disorders Exclusion Criteria: Uncontrolled or unstalbe medical condition Pregnant Scalp problem which interferese with tDCS metals in the head (example: clip, coil), cochlear implants

Ages Eligible for Study
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Minimum Age: 19 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: sham tDCS- washout period- anodal tDCS<br>Ybrain tDCS System (Ybrain, Korea) is used. Anode of tDCS is placed over right cerebellar hemisphere (3cm lateral from the occipital protuberance) and cathode over the on ipsilateral buccinator muscle. For Sham tDCS, total stimulation lasts 90 seconds: ramp up period of 30 seconds, stimultation for intensity of 2mA for 30 seconds, and ramp down period of 30 seconds. At least 7 days of washout period is in between two tDCS. For Anodal tDCS, 20 minutes of stimulation for intensity of 2mA. | Device: tDCS<br>* Ybrain tDCS System (Ybrain, Korea) is used for anodal stimulation of cerebellar hemisphere. Anode of tDCS is placed over right cerebellar hemisphere (3cm lateral from the occipital protuberance) and cathode over the on right buccinator muscle.<br>|
| Active Comparator: anodal tDCS- washout period- sham tDCS<br>Ybrain tDCS System (Ybrain, Korea) is used. Anode of tDCS is placed over right cerebellar hemisphere (3cm lateral from the occipital protuberance) and cathode over the on ipsilateral buccinator muscle. For Anodal tDCS, 20 minutes of stimulation for intensity of 2mA. At least 7 days of washout period is in between two tDCS. For Sham tDCS, total stimulation lasts 90 seconds: ramp up period of 30 seconds, stimultation for intensity of 2mA for 30 seconds, and ramp down period of 30 seconds. | Device: tDCS<br>* Ybrain tDCS System (Ybrain, Korea) is used for anodal stimulation of cerebellar hemisphere. Anode of tDCS is placed over right cerebellar hemisphere (3cm lateral from the occipital protuberance) and cathode over the on right buccinator muscle.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of concentration of deoxyhemoglobin | detected by fNIRS and implies cortical metabolic changes | comparison between sham and anodal tDCS (at least 7 days apart) | 
| Changes of concentration of oxyhemoglobin | detected by fNIRS and implies cortical metabolic changes | comparison between sham and anodal tDCS (at least 7 days apart) |