Cortical Enhancement of Posture, Movement Planning, and Execution of Upright Reaching Following Stroke

Study Overview
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Brief Summary
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Stroke is the leading cause of disability and diminished quality of living that frequently includes impairments of postural control and upper extremity (UE) function. The interaction of posture and UE coupling in terms of movement planning, initiation, and execution is not well understood. StartReact responses triggered by a loud acoustic stimulus (LAS) during the planning and preparation of goal intended actions has been used to probe the state of brainstem neuronal excitability related to posture and movement sequencing. The purpose of this study is to examine posture and goal-directed movement planning and execution using startReact responses and to evaluate posture and UE movement sequence during reaching while standing in individuals with chronic hemiparesis and healthy controls. Secondly, the investigators will determine the modulatory role of the cortical premotor areas (PMAs) in startReact responses in healthy controls and in persons with stroke by using transcranial direct current stimulation (tDCS) to up- or down-regulate PMAs excitability.

Official Title
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Cortical Enhancement of Posture, Movement Planning, and Execution of Upright Reaching Following Stroke

Conditions
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Stroke, Upper Extremity Paresis

Intervention / Treatment
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* Other: Transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria for stroke: Unilateral cortical or white matter subcortical stroke Age 40 yrs and older ≥ 6 months post ischemic stroke or ≥ 12 months post hemorrhagic stroke Residual arm hemiparesis as indicated by Fugl-Meyer Upper Extremity score between 20-65 Having the ability to perform reaching movements with the paretic arm in standing without an assistive device. Exclusion Criteria for stroke: Stroke involving bilateral hemisphere, brainstem or cerebellum Any medical condition precluding participation in testing Other health conditions affecting balance and upper extremity movement function beyond the effects of stroke. Inclusion Criteria for healthy controls: Age-matched to the stroke subjects Without a history of stroke or any known neurological conditions Having the cognitive ability to follow two-step commands and give informed consent Exclusion Criteria for healthy controls: Any medical condition precluding participation in testing Other health conditions affecting balance and upper extremity movement function beyond the effects of stroke. Participants were also excluded if they did not meet the TMS safety criterion including having implantable medical devices, history of seizures, taking medications to reduce anxiety, sedatives, and seizure, and pregnancy.

Ages Eligible for Study
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Minimum Age: 40 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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: tDCS over PMAs<br>One session of transcranial direct current stimulation (tDCS) over premotor areas (PMAs) | Other: Transcranial direct current stimulation<br> <br> |
| Active Comparator: tDCS over M1<br>One session of transcranial direct current stimulation (tDCS) over primary motor area (M1) | Other: Transcranial direct current stimulation<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in startReact response | The incidence of StartReact response following an loud acoustic stimulus | Immediately after the intervention (one session tDCS) | 
| Change in the lag between anticipatory postural adjustments and reach onset | The temporal lag between anticipatory postural adjustments (APA) onset and reach onset (unit: seconds) | Immediately after the intervention (one session tDCS) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in the reach onset (unit: seconds) | The onset of the anterior wrist joint center movement with a threshold of 5% peak velocity | Immediately after the intervention (one session tDCS) | 
| Change in the APA onset (unit: seconds) | The onset of the posterior center of pressure displacement with a threshold of 5% peak velocity | Immediately after the intervention (one session tDCS) | 
| Change in the amount of trunk flexion (unit: radians) | The angular displacement of the line joining the reaching shoulder and the hip joint center on the same side in the sagittal plane at maximum reach normalized by reach distance | Immediately after the intervention(one session tDCS) | 
| Change in the amount of trunk rotation (unit: radians) | The angular displacement of the line connecting both shoulders in the horizontal plane in the direction of the reach at maximum reach normalized by reach distance | Immediately after the intervention (one session tDCS) | 
| Change in the amount of pelvic rotation (unit: radians) | The angular displacement of the line connecting both hip joint centers in the horizontal plane in the direction of the reach at maximum reach normalized by reach distance | Immediately after the intervention (one session tDCS) | 
| Change in the amount of trunk-pelvic rotation difference (unit: radians) | The difference between trunk and pelvic angular displacement at maximum reach normalized by reach distance | Immediately after the intervention (one session tDCS) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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StartReact response, transcranial direct current stimulation, Postural control