Noninvasive Brain Stimulation to Evaluate Neural Plasticity After Stroke

Study Overview
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Brief Summary
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The purpose of this study is to examine how different areas in the brain interact with each other and how using brain imaging and brain stimulation approaches can influence these interactions.

Detailed Description
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Subcortical strokes affect small vessels deep in the brain, and typically present with motor hemiparesis. The investigator will assess the effects of Transcranial Magnetic Stimulation (TMS) on motor function and examine how different areas in the human brain interact with each other using brain imaging and brain stimulation. The investigator will also evaluate the capacity for noninvasive stimulation to transiently modify brain activity supporting arm movement.

Official Title
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Noninvasive Brain Stimulation to Evaluate Neural Plasticity After Stroke

Conditions
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Cerebrovascular Stroke

Intervention / Treatment
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* Device: Transcranial Magnetic Stimulation
* Device: Traditional Paired Associative Stimulation
* Device: Median Nerve Stimulation
* Device: Corticocortical Paired Associative Stimulation
* Device: Sham Paired Associative Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18-85 years Middle cerebral artery stroke Individuals with a first time stroke that affects the corona radiata and/or internal capsule Exclusion Criteria: Age outside the age range of 18-85 years Signs of dementia (score < 24 on the Montreal Cognitive Assessment) Aphasia (score < 13 on the Frenchay Aphasia Screen) History of head trauma History of a major psychiatric diagnosis History of a neurodegenerative disorder History of substance abuse Contraindications to Transcranial Magnetic Stimulation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 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: Basic Science
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Subcortical stroke<br>Subjects with subcortical stroke in the chronic phase of recovery with mild-moderate impairment of arm function will undergo noninvasive targeting of cortical locations by stereotactic neuronavigation using Transcranial Magnetic Stimulation (TMS), median nerve stimulation and arm motor function assessments. A paired associative stimulation (PAS) protocol using noninvasive stimulation will also be used which will be one of the following, a traditional or a corticocortical or a sham paired associative stimulation protocol. The subjects will also undergo median nerve stimulation. | Device: Transcranial Magnetic Stimulation<br>* Transcranial Magnetic Stimulation (TMS) will be performed using the Magstim BiStim^2 paired pulse stimulator to measure transient cortical excitability. Single pulse transcranial magnetic stimulation applied at low frequencies (not greater than 0.25 hertz (Hz)) will be used. The may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;Device: Traditional Paired Associative Stimulation<br>* Paired associative stimulation (PAS) is a combination of transcranial magnetic stimulation (TMS) and electrical stimulation of the median nerve. 180 paired stimuli are delivered at 0.25 Hz for 12 minutes. Median nerve stimuli at 300% of the perceptual threshold will be applied 25ms prior to transcranial magnetic stimulation delivery over the ipsilesional (stroke) or non-dominant (control) cortex. Transcranial Magnetic Stimulation (TMS) will be performed using the Magstim BiStim^2 paired pulse stimulator unit and a bipolar bar electrode will be used for median nerve stimulation. This traditional paired associative stimulation may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;Device: Median Nerve Stimulation<br>* Stimulation of the median nerve will be performed using a bipolar bar electrode affixed to palmar aspect of the forearm proximal to the crease of the wrist bilaterally. Stimuli will be delivered 23ms prior to the transcranial magnetic stimulation (TMS) pulse with 0.1 milliseconds (ms) rectangular pulses at an intensity to evoke a 1 millivolt (mV) response in the abductor pollicis brevis (APB) muscle. This may may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>Device: Corticocortical Paired Associative Stimulation<br>* Cortico-cortical Paired Associative Stimulation (CC-PAS) is a combination of TMS and electrical stimulation of the median nerve. 180 paired stimuli are delivered at 0.25 Hz for 12 minutes. The interstimulus interval will range from 5-15 ms depending on site of stimulation.TMS will be performed using the Magstim BiStim^2 paired pulse stimulator unit and a bipolar bar electrode will be used for median nerve stimulation. This CC-PAS may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;Device: Sham Paired Associative Stimulation<br>* The sham PAS is a combination of TMS and electrical stimulation of the median nerve. The coil is rotated and separated from the head with a plastic spacer to ensure indirect contact with the head.180 paired stimuli are delivered at 0.25 Hz for 12 minutes. TMS will be performed using the Magstim BiStim^2 paired pulse stimulator unit and a bipolar bar electrode will be used for median nerve stimulation. This sham paired associative stimulation may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;|
| Active Comparator: Healthy Control<br>Healthy individuals will undergo noninvasive targeting of cortical locations by stereotactic neuronavigation using Transcranial Magnetic Stimulation (TMS), median nerve stimulation and arm motor function assessments. A paired associative stimulation (PAS) protocol using noninvasive stimulation will also be used which will be one of the following, a traditional or a corticocortical or a sham paired associative stimulation protocol. | Device: Transcranial Magnetic Stimulation<br>* Transcranial Magnetic Stimulation (TMS) will be performed using the Magstim BiStim^2 paired pulse stimulator to measure transient cortical excitability. Single pulse transcranial magnetic stimulation applied at low frequencies (not greater than 0.25 hertz (Hz)) will be used. The may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;Device: Traditional Paired Associative Stimulation<br>* Paired associative stimulation (PAS) is a combination of transcranial magnetic stimulation (TMS) and electrical stimulation of the median nerve. 180 paired stimuli are delivered at 0.25 Hz for 12 minutes. Median nerve stimuli at 300% of the perceptual threshold will be applied 25ms prior to transcranial magnetic stimulation delivery over the ipsilesional (stroke) or non-dominant (control) cortex. Transcranial Magnetic Stimulation (TMS) will be performed using the Magstim BiStim^2 paired pulse stimulator unit and a bipolar bar electrode will be used for median nerve stimulation. This traditional paired associative stimulation may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;Device: Median Nerve Stimulation<br>* Stimulation of the median nerve will be performed using a bipolar bar electrode affixed to palmar aspect of the forearm proximal to the crease of the wrist bilaterally. Stimuli will be delivered 23ms prior to the transcranial magnetic stimulation (TMS) pulse with 0.1 milliseconds (ms) rectangular pulses at an intensity to evoke a 1 millivolt (mV) response in the abductor pollicis brevis (APB) muscle. This may may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>Device: Corticocortical Paired Associative Stimulation<br>* Cortico-cortical Paired Associative Stimulation (CC-PAS) is a combination of TMS and electrical stimulation of the median nerve. 180 paired stimuli are delivered at 0.25 Hz for 12 minutes. The interstimulus interval will range from 5-15 ms depending on site of stimulation.TMS will be performed using the Magstim BiStim^2 paired pulse stimulator unit and a bipolar bar electrode will be used for median nerve stimulation. This CC-PAS may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;Device: Sham Paired Associative Stimulation<br>* The sham PAS is a combination of TMS and electrical stimulation of the median nerve. The coil is rotated and separated from the head with a plastic spacer to ensure indirect contact with the head.180 paired stimuli are delivered at 0.25 Hz for 12 minutes. TMS will be performed using the Magstim BiStim^2 paired pulse stimulator unit and a bipolar bar electrode will be used for median nerve stimulation. This sham paired associative stimulation may be repeated at multiple study visits. All five study visits will be completed within four weeks of the initial visit.<br>* Other names: Magstim BiStim^2;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Long-term Potentiation-like Plasticity | Long-term potentiation-like plasticity was measured using paired associative stimulation (PAS). PAS consists of repeated peripheral electric stimulation paired with Transcranial Magnetic Stimulation (TMS) applied to the motor cortex at varying interstimulus intervals. Participants received 180 paired stimuli at 0.25 hertz (Hz) for 12 minutes. Impaired long-term potentiation-like plasticity points towards reduced excitatory synaptic connectivity and deficits in sensorimotor integration. Decrease or no change in the amplitudes of motor-evoked potentials (MEPs) indicates impaired long-term potentiation-like plasticity. | Baseline, 1 Minute Post-Paired Associative Stimulation | 
| Electroencephalography Recordings at Baseline and 5 MInutes Post-PAS | Electroencephalography (EEG) data were recorded using a 64-channel TMS-compatible electrode cap (Easy Cap). Signals were collected at 2000 hertz (Hz) during pre- and post-transcranial magnetic stimulation epochs (-100ms to 200ms). Up to fifty suprathreshold (120% AMT) transcranial magnetic stimulation pulses were applied to motor cortex while the subject was seated quietly with eyes open. This procedure was conducted bilaterally. Data epochs (-1000 to 4000 ms with respect to TMS delivery) were extracted for subsequent imaginary phase coherence analysis. Post-TMS coherence values between electrodes overlying M1 bilaterally (C3 and C4) were calculated within the beta frequency range (15 to 30 Hz). EEG data values are unit-free that can range from 0 to 1. Higher values represent greater coherence which is thought to indicate stronger connectivity. | Baseline, 5 Minutes Post-Paired Associative Stimulation | 
| Abbreviated Wolf Motor Function Test Time | Three items of the Wolf Motor Function Test (WMFT) were used to evaluate functional motor performance. The 3 items were selected based on task difficulty ranging from easiest (hand to table) to most difficult (stack checkers) along with a task of moderate difficulty (lift can). Each task has different control demands and number of actions required to complete successfully. Task performance is timed in seconds, with a maximum time of 120 seconds. | Baseline, 10 Minutes Post-Paired Associative Stimulation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Wolf Motor Function Test | The arm function in subjects in the subcortical stroke group was evaluated by the Wolf Motor Function Test (WMFT). The test consists of timed and functional tasks and has 17 items. It is composed of 3 parts: Time, functional ability and strength and includes 15 function-based tasks and 2 strength based tasks. Items 1-6 involve timed functional tasks, items 7-14 are measures of strength, and the remaining 9 items consist of analyzing movement quality when completing various tasks. The examiner will test the less affected upper extremity followed by the most affected side. Scores are based on time taken to complete each task. The median time to complete all tasks will be be used to evaluate motor function. Larger values indicate greater upper extremity motor dysfunction. | Baseline | 
| Abbreviated Wolf Motor Function Test Time | Three items of the WMFT were used to evaluate functional motor performance. The 3 items were selected based on task difficulty ranging from easiest (hand to table) to most difficult (stack checkers) along with a task of moderate difficulty (lift can). Each task has different control demands and number of actions required to complete successfully. Task performance will be timed, with a maximum time of 120 seconds. | 30 minutes post-Paired Associative Stimulation, 24 hours post-Paired Associative Stimulation | 
| Long-term Potentiation-like Plasticity | Long-term potentiation-like plasticity was measured using paired associative stimulation (PAS). PAS consists of repeated peripheral electric stimulation paired with Transcranial Magnetic Stimulation (TMS) applied to the motor cortex at varying interstimulus intervals. Participants receive 180 paired stimuli at 0.25 Hz for 12 minutes. Impaired long-term potentiation-like plasticity points towards reduced excitatory synaptic connectivity and deficits in sensorimotor integration. Decrease or no change in the amplitudes of motor-evoked potentials (MEPs) indicates impaired long-term potentiation-like plasticity. | 30 minutes post-Paired Associative Stimulation, 24 hours post-Paired Associative Stimulation | 
| Electroencephalography Recordings at 30 Minutes and 24 Hours Post-PAS | Electroencephalography (EEG) data were recorded using a 64-channel TMS-compatible electrode cap (Easy Cap). Signals were collected at 2000 hertz (Hz) during pre- and post-transcranial magnetic stimulation epochs (-100ms to 200ms). Up to fifty suprathreshold (120% AMT) transcranial magnetic stimulation pulses were applied to motor cortex while the subject was seated quietly with eyes open. This procedure was conducted bilaterally. Data epochs (-1000 to 4000 ms with respect to TMS delivery) were extracted for subsequent imaginary phase coherence analysis. Post-TMS coherence values between electrodes overlying M1 bilaterally (C3 and C4) were calculated within the beta frequency range (15 to 30 Hz). EEG data values are unit-free that can range from 0 to 1. Higher values represent greater coherence which is thought to indicate stronger connectivity. | 30 minutes post-Paired Associative Stimulation, 24 hours post-Paired Associative Stimulation | 
| Serial Reaction Time Task (SRTT) Performance | The SRTT involves pressing a key that corresponds to a target square positioned on a screen in front of the participant as quickly and accurately as possible. The response time for repeated and random sequences evaluate SRTT performance and skill is measured as the difference in response times between repeated and random sequences. Lower response times indicate better performance and a larger positive difference in response times represents greater sequence-specific skill. Negative values represent better performance on random sequences compared to repeated sequences. | Baseline, 10 minutes post-PAS, 30 minutes post-PAS, and 24 hours post-PAS | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Neural plasticity, Noninvasive brain stimulation, Motor cortex