Parameter Space of kTMP

Study Overview
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Brief Summary
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The investigators have recently developed a new non-invasive brain stimulation (NIBS) system, kilohertz transcranial magnetic perturbation (kTMP) that opens up a new experimental space for safely modulating neural excitability in targeted areas of the human brain. This project will characterize the broad parameter space of kTMP in terms of tolerability and efficacy in healthy individuals. Following earlier feasibility studies, we are now increasing our number of subjects in order to capture preliminary safety and effectiveness information on a near-final device.

Detailed Description
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Non-invasive brain stimulation (NIBS) has attracted considerable interest in the cognitive neuroscience community, providing an important basic research tool to study brain function, with emerging clinical applications to enhance function in individuals with neurological disorders. The investigators have developed a radically new NIBS approach, one in which subthreshold modulation of neural excitability is brought about via oscillating magnetic fields at kilohertz (kHZ) frequencies. This system, referred to kTMP (kHz Transcranial Magnetic Perturbation) significantly increases the range of subthreshold E-field induction, and through modulation of the envelope of the kHz carrier frequency, can impose E-fields at physiological relevant frequencies. The investigators will conduct testing with healthy human participants to assess the tolerability and efficacy of the system in producing changes in cortical physiology.

Official Title
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Exploring the Parameter Space of High Frequency Magnetic Perturbation in Manipulating Neural Excitability and Plasticity.

Conditions
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Healthy

Intervention / Treatment
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* Device: kTMP
* Device: Sham kTMP


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-75 Exclusion Criteria: serious medical condition had a seizure of any sort epilepsy or experienced seizures neurological disorder head injury stroke had any form of brain surgery history of migraine metal implants in your head, excluding the mouth pacemaker implanted medical devices of any sort pregnant hearing loss or hearing impairments jet lag stress substance abuse highly stressful event over the past 24 hours broken or abnormal skin on your scalp

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 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: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: active kTMP<br>Participants received 0.5 - 8 V/m of active stimulation. | Device: kTMP<br>* a new non-invasive brain stimulation tool<br>|
| Sham Comparator: sham kTMP<br>Participants received 0.01 V/m of sham stimulation. | Device: Sham kTMP<br>* a new non-invasive brain stimulation tool with sham setting selected<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Self-reported sensation/discomfort through questionnaire during kTMP stimulation. | As per the FDA's guidance (www.fda.gov/media/81784/download) on device feasibility studies, initiation of an early feasibility study must be justified by an appropriate benefit-risk analysis and adequate human subject protection measures. This outcome measures device feasibility in terms of device tolerability. To estimate the stimulation threshold, the investigators will use an adaptive procedure in which they sequentially increase the stimulation intensity (E-field amplitude) and register self-reports of sensation. Stimulation intensity will start from 0.01 V/m (sham) increasing 0.5 V/m at a time for 16 trials until it reaches 7.6 V/m. Participants provided three ratings using an 11-point scale (0 = not at all; 10 = extremely) in response to questions on annoyance, pain, and muscle twitching. (How annoying was kTMP?, How painful was kTMP?, and If there were any muscle twitches from the kTMP, how strong were they?) A higher score means more sensation/discomfort. | Measures will be obtained 4-5 seconds after each kTMP stimulation at a specific E-field (when the visual display appears on the screen), in total 16 times throughout the kTMP stimulation trial. | 
| Self-reported sensation/discomfort through questionnaire after kTMP stimulation. | As per the FDA's guidance (www.fda.gov/media/81784/download) on device feasibility studies, initiation of an early feasibility study must be justified by an appropriate benefit-risk analysis and adequate human subject protection measures. This outcome measures device feasibility in terms of device tolerability. After the kTMP stimulation, the investigators will register self-reports of sensation from the participant to see any lasting effect in terms of sensation. Participants provided three ratings using an 11-point scale (0 = not at all; 10 = extremely) in response to questions on annoyance, pain, and muscle twitching. (How annoying was kTMP?, How painful was kTMP?, and If there were any muscle twitches from the kTMP, how strong were they?) A higher score means more sensation/discomfort. | Measures will be obtained 1 minute after kTMP stimulation. | 
| Motor evoked potential (MEPs) amplitude recorded with electromyography (EMG) before kTMP stimulation. | This outcome measures device feasibility in terms of efficacy, as MEP changes indicate changes in cortical excitability induced by kTMP. As an operational definition of cortical excitability, the investigators will measure MEPs recorded in a peripheral hand muscle through the EMG system. The threshold procedure will be first conducted using single-pulse Transcranial magnetic stimulation (TMS) to find the M1 hotspot and threshold intensity. Once the threshold is set, MEPs will be obtained using the single-pulse and paired-pulse TMS procedures. These measurements will be taken prior to the experimental intervention of kTMP to obtain a baseline measure. | Measures will be obtained from 0 to 15 minutes before the stimulation. | 
| Motor evoked potential (MEPs) amplitude recorded with EMG after kTMP stimulation. | This outcome measures device feasibility in terms of efficacy, as MEP changes indicate changes in cortical excitability induced by kTMP. After the kTMP stimulation as a plasticity-inducing technique, we obtain MEPs using the single-pulse and paired-pulse TMS procedures. MEPs will be recorded in a peripheral hand muscle through the EMG system. The primary intervention of interest is the kTMP system, with various manipulations of the parameter settings. | Measures will be obtained 1 hour 30 minutes after the stimulation. |