Transcranial Alternating Current Stimulation for Hand Function Recovery

Study Overview
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Brief Summary
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tACS has the potential to directly induce cortical alterations in the intrinsic neural oscillation at specific frequencies, and the brain could mirror the induced frequencies of the external source of oscillations from the stimulation. Hence, tACS with matching stimulation frequency could be an effective means of enhancing brain oscillatory activity to potentially induce synaptic plasticity for restoration of damaged brain functions. However from the existing studies of applying tACS over the M1 in healthy and diseased brains, there is a wide range of applied stimulation frequencies and varied neuromodulation effects on motor behavior or cortical excitability at different frequencies. In this proposal, subject-specific stimulation frequency and latency will be identified.

Official Title
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Design of Synchronized Pairing Peripheral Nerve Stimulation and Cortical Polarization to Promote Post-stroke Neuroplasticity for Hand Function Recovery

Conditions
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Stroke

Intervention / Treatment
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* Device: tACS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Hemiparesis subsequent to first-ever unilateral stroke for more than 6 months; MCP and PIP finger joints can be extended to 180° passively; Sufficient cognition to follow the experimental instructions Exclusion Criteria: Severe hand spasticity or hand deformity; History of alcohol or drug abuse or epilepsy; Bilateral brain infarcts; Severe cognitive deficits; Comprehensive aphasia; Contraindications to tACS and MRI

Ages Eligible for Study
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Minimum Age: 18 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: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: subject-specific tACS<br>Constant current (1mA) will be applied for 20min at subject-specific stimulation frequency and latency | Device: tACS<br>* A pair of 25 cm2 rubber electrodes enclosed in saline-soaked sponges and affixed to the head with rubber bands.<br>|
| Experimental: standard tACS<br>Constant current (1mA) will be applied for 20min at 20Hz with a fixed 25ms latency | Device: tACS<br>* A pair of 25 cm2 rubber electrodes enclosed in saline-soaked sponges and affixed to the head with rubber bands.<br>|
| Sham Comparator: Sham tACS<br>The stimulator will be shut down after 30s of stimulation. The patients will feel the initial itching sensation at the beginning in order to evaluate the placebo effect | Device: tACS<br>* A pair of 25 cm2 rubber electrodes enclosed in saline-soaked sponges and affixed to the head with rubber bands.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Magnetic resonance imaging | Structural and functional MRI | 3-month after the 10th session training | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Action Research Arm Test (ARAT) | The ARAT has total 19 items, divided into 4 categories (grasp, grip, pinch, and gross arm movement). It ranges from 3 to 0 (best to worse). | 3-month after the 10th session training | 
| Fugl-Meyer Assessment (Upper Extremity) | The maximum score is 66, divided into 33 items in the form of a 3-point scale (0-2), 0 is cannot perform and 2 performs fully. | 3-month after the 10th session training | 
| Wolf Motor Function Test (WMFT) | The WMFT measures upper limb ability through timed and functional tasks. It has 17 items, ranging from 0 to 5 (worse to best). | 3-month after the 10th session training |