Developing Optimal Focal Muscle Vibration for Improving Spasticity

Study Overview
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Brief Summary
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The overall aim of the proposed study is to determine optimal parameter of focal muscle vibration for improving spasticity and identify neurophysiological mechanism in healthy subjects. In investigation I-1, subjects will undergo focal muscle vibration with 40, 80, 120 Hz frequency at the medial gastrocnemius muscles (mGCM). As a surrogate maker of spasticity, H-reflex and compound motor action potential (CMAP) of the tibial nerve at mGCM will be recorded pre, during, and post vibration. In investigation I-2, subjects will undergo focal muscle vibration with 0.1, 0.3, 0.5 mm amplitude at mGCM. H-reflex and CMAP of the tibial nerve at mGCM will be recorded pre, during, and post vibration. In investigation II, subjects will undergo focal muscle vibration with predetermined parameters by the investigation I at mGCM. H-reflex and CMAP of the tibial nerve and motor evoked potential at mGCM will be recorded pre, during, and post vibration.

Official Title
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Optimization of Physical Focal Stimulation Parameters for Improving Spasticity and Identification of Neurophysiological Mechanism

Conditions
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Vibration, Electrophysiology, Muscle Spasticity

Intervention / Treatment
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* Device: Focal muscular vibration


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy volunteer Exclusion Criteria: Unstable medical conditions History of epilepsy History of drug abuse

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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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Focal muscle vibration<br>Focal muscular vibration will be applied at mGCM of each subject for 10 minutes in each session. Frequency: 40, 80, 120 Hz Amplitude: 0.1, 0.3, 0.5 mm | Device: Focal muscular vibration<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| H/M ratio | The ratio of maximal H-reflex amplitude (mV) to CMAP amplitude (mV) recorded at mGCM | baseline, 1, 5 and 10 minutes during vibration, and 1 and 5 minutes after vibration | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| H amplitude | maximal H-reflex amplitude (mV) recorded at mGCM | baseline, 1, 5 and 10 minutes during vibration, and 1 and 5 minutes after vibration | 
| M amplitude | CMAP amplitude (mV) recorded at mGCM | baseline, 1, 5 and 10 minutes during vibration, and 1 and 5 minutes after vibration | 
| motor evoked potential (MEP) amplitude | Transcranial magnetic stimulation on the contralateral leg motor cortex is used to measure MEP at mGCM. | baseline, 10 minutes during vibration, and 5 minutes after vibration | 
| Resting motor threshold (RMT) | Resting motor threshold (%) is defined as the minimal intensity of TMS capable of inducing MEPs greater than 100μV peak-to-peak amplitude in at least 3 of 5 trials. | baseline, 10 minutes during vibration, and 5 minutes after vibration | 
| Short interval intracortical inhibition | Short interval intracortical inhibition is recorded by using conditioning stimulus of 90% RMT and test stimulus of 120% RMT with 1ms interval. | baseline, 10 minutes during vibration, and 5 minutes after vibration | 
| Intracortical facilitation | Intracortical facilitation is recorded by using conditioning stimulus of 90% RMT and test stimulus of 120% RMT with 10ms interval. | baseline, 10 minutes during vibration, and 5 minutes after vibration | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Monosynaptic reflex, H-reflex