Re-Orchestration of Interregional Oscillatory Activity to Promote Visual Recovery

Study Overview
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Brief Summary
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This project assesses the effect of bifocal cross-frequency transcranial alternating current stimulation (tACS) combined with visual training to improve visual recovery and orchestrated oscillatory activity in stroke patients suffering from visual field defects.

Official Title
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Individualized Brain Stimulation to Improve Functional Rehabilitation in Two Models of Sensorimotor Disorders: Stroke and Parkinson's Disease

Conditions
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Visual Impairment, Stroke, Parkinson Disease

Intervention / Treatment
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* Other: Cross-frequency dual-site tACS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: the patient can consent for themselves; age 18+ years old; at least 7 days since diagnosis stroke. Patients should demonstrate a clear deficit in either simple or complex visual perception in portions of their visual field Exclusion Criteria: Diminished capacity to consent; Pregnancy Known or suspected non-compliance, drug or alcohol abuse Inability to follow the procedures of the study, e.g., due to language problems, psychological disorders, dementia, etc. of the participant, Non-compliance to the instructions of the experimenter or an inappropriate behavior hindering the normal progress of the experiment. Previous enrolment into the current study Exclusion criteria of MRI, tACS, TMS Use of psychoactive medication

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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No

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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Cf-tACS (V1-Alpha_V5-Gamma)<br> | Other: Cross-frequency dual-site tACS<br>* Dual site transcranial alternating current stimulation over the primary visual cortex (V1) and the mediotemporal cortex (MT/V5) using two different stimulation frequencies (Alpha and Gamma)<br>|
| Experimental: Cf-tACS (V1-Gamma_V5-Alpha)<br> | Other: Cross-frequency dual-site tACS<br>* Dual site transcranial alternating current stimulation over the primary visual cortex (V1) and the mediotemporal cortex (MT/V5) using two different stimulation frequencies (Alpha and Gamma)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in visual field functions | Comparison of the systematic measurement of the visual field using Humphrey perimetry | Measured at baseline (i.e. before the first day of intervention), and post intervention (i.e., after the last day of intervention) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in motion discrimination and integration performances | Comparison of the motion coherence threshold extracted from a two forced-choice direction discrimination task | Measured at baseline (i.e. before the first day of intervention), and post intervention (i.e., after the last day of intervention) | 
| Changes in inter-areal cross-frequency interaction | Comparison of the inter-areal Alpha-Gamma coupling using electroencephalography recordings | Measured at baseline (i.e. before the first day of intervention), and post intervention (i.e., after the last day of intervention) | 
| Changes in visual tracts integrity | Comparison of the diffusion weigted imaging-based tractography of the main visual tracts | Measured at baseline (i.e. before the first day of intervention), and post intervention (i.e., after the last day of intervention) | 
| Changes in functional connectivity within the broad visual network | Functional MRI based connectivity analyses using DCM or graph theory will perfomed | Measured at baseline (i.e. before the first day of intervention), and post intervention (i.e., after the last day of intervention) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Stroke, Visual field, Oscillations, tACS, Parkinson's Disease