Primed vs Unprimed Facilitatory and Depressive Paired Associative Stimulation

Study Overview
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Brief Summary
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Following brain injury (e.g. stroke), application of non-invasive brain stimulation may improve rehabilitative efforts. However, the most effective method of non-invasive brain stimulation is unknown. Paired associative stimulation (PAS) is a method of non-invasive brain stimulation that pairs an electrical peripheral nerve stimulus with a magnetic stimulus to the head. This method can be applied in a manner that increases (facilitates) or decreases (depresses) excitability within the brain. Furthermore, applying two consecutive PAS sessions within minutes of each other (called primed PAS) may augment changes in excitability more than a single PAS session alone. Thus, the purpose of this study is to compare the effect of a double PAS session (primed PAS) to the effect of a single PAS session (unprimed PAS) and a sham PAS session in healthy individuals.

Official Title
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Primed vs Unprimed Facilitatory and Depressive Paired Associative Stimulation

Conditions
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Healthy

Intervention / Treatment
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* Device: Transcranial Magnetic Stimulation (Magstim)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ≥ 18 and ≤ 30 years of age Elicitable motor evoked potential from the motor cortex contralateral to the dominant hand Elicitable N20 sensory evoked potential Exclusion Criteria: History of neurological disease Seizure within the past 2 years Currently taking epileptogenic medication Peripheral neuropathy Cognitive impairment and/or major psychiatric disorder Metal in the head (dental permitted) Pacemaker or other indwelling devices Pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 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: Device Feasibility
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Primed PAS 1A<br>Two sessions of paired associative stimulation (PAS) using transcranial magnetic stimulation will be applied consecutively (within minutes). | Device: Transcranial Magnetic Stimulation (Magstim)<br> <br> * Other names: Magstim;|
| Experimental: Unprimed PAS 1B<br>A single session of active paired associative stimulation (PAS) using transcranial magnetic stimulation will be applied. | Device: Transcranial Magnetic Stimulation (Magstim)<br> <br> * Other names: Magstim;|
| Sham Comparator: Sham PAS<br>A single session of sham paired associative stimulation (PAS) using transcranial magnetic stimulation will be applied | Device: Transcranial Magnetic Stimulation (Magstim)<br> <br> * Other names: Magstim;|
| Experimental: Primed PAS 2A<br>Two sessions of paired associative stimulation (PAS) using transcranial magnetic stimulation will be applied consecutively (within minutes). | Device: Transcranial Magnetic Stimulation (Magstim)<br> <br> * Other names: Magstim;|
| Experimental: Unprimed PAS 2B<br>A single session of active paired associative stimulation (PAS) using transcranial magnetic stimulation will be applied. | Device: Transcranial Magnetic Stimulation (Magstim)<br> <br> * Other names: Magstim;|
| Experimental: Primed PAS 1C<br>Two sessions of paired associative stimulation (PAS) using transcranial magnetic stimulation will be applied consecutively (within minutes). | Device: Transcranial Magnetic Stimulation (Magstim)<br> <br> * Other names: Magstim;|
| Experimental: Primed PAS 2C<br>Two sessions of paired associative stimulation (PAS) using transcranial magnetic stimulation will be applied consecutively (within minutes). | Device: Transcranial Magnetic Stimulation (Magstim)<br> <br> * Other names: Magstim;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline peak-to-peak amplitude of motor evoked potential | Single-pulse TMS will be used to evoke a motor response that is recorded using electromyography (EMG). The peak-to-peak amplitude of the EMG response will be measured. | Immediately before and within 60 minutes following intervention | 
| Change from baseline resting motor threshold | Single-pulse TMS will be used to evoke a motor response that is recorded using electromyography (EMG). The lowest stimulator output needed to elicit a consistent response will be recorded. | Immediately before and within 60 minutes following intervention |