Repetitive Transcranial Magnetic Stimulation for the Treatment of Focal Hand Dystonia

Study Overview
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Brief Summary
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This study investigated the short term effects of repeated administrations of repetitive-transcranial magnetic stimulation (rTMS) on clinical changes and investigate neurophysiologic responses to rTMS of the activated motor system in patients with FHD.

Detailed Description
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Purpose: The ability of low-frequency repetitive transcranial magnetic stimulation (rTMS) to enhance intracortical inhibition has motivated its use as a potential therapeutic intervention in focal hand dystonia (FHD). In this preliminary investigation, we assessed the physiologic and behavioral effects of multiple sessions of rTMS in FHD. Methods: 12 patients with FHD underwent five daily-sessions of 1 Hz rTMS to contralateral dorsal premotor cortex (dPMC). Patients held a pencil and made movements that did not elicit dystonic symptoms during rTMS. We hypothesized that an active but non-dystonic motor state would increase beneficial effects of rTMS. Five additional patients received sham-rTMS protocol. The area under curve (AUC) of the motor evoked potentials and the cortical silent period (CSP) were measured to assess changes in corticospinal excitability and intracortical inhibition, respectively. Behavioral measures included pen force and velocity during handwriting and subjective report.

Official Title
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Multiple Sessions of Low-frequency Repetitive Transcranial Magnetic Stimulation in Focal Hand Dystonia: Clinical and Physiological Effects

Conditions
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Dystonia, Focal, Task-specific

Intervention / Treatment
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* Device: rTMS
* Device: Sham rTMS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Task specific Focal Hand Dystonia Exclusion Criteria: any neurologic condition other than FHD medication for dystonia botulinum toxin within the past three months seizure history pregnancy implanted medical devices

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: inhibitory rTMS<br>Repetitive Transcranial Magnetic stimulation: 1 Hz rTMS, 1800 pulses, delivered to premotor cortex. Patients held a pencil and made movements that did not elicit dystonic symptoms during rTMS. Intervention was delivered every day for 5 days. | Device: rTMS<br>* rTMS<br>* Other names: Magstim Rapid 2, Magstim Co, Whitland Dyfed, UK;|
| Placebo Comparator: Sham rTMS<br>Sham Repetitive Transcranial Magnetic stimulation: 1 Hz rTMS, 1800 pulses, delivered to premotor cortex. Patients held a pencil and made movements that did not elicit dystonic symptoms during rTMS. Intervention was delivered every day for 5 days. | Device: Sham rTMS<br>* Sham rTMS<br>* Other names: Placebo Magstim Rapid 2, Magstim Co, Whitland Dyfed, UK;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cortical Silent Period | Subjects performed an isometric abduction contraction of the index finger against a strain gauge coupled to a load cell. A single TMS pulse was applied 2-3 s after contraction initiation and subjects were instructed to relax 2-3 s after stimulation. The duration of the CSP was measured on a trial-by-trial basis and was delineated by the first superimposed TMS-evoked EMG spike (onset) and the return of activity to 50% of prestimulus EMG signal (offset). The mean CSP duration was calculated for each block of measurements. The duration of CSP is thought to be related to intracortical GABAergic synapse-mediated inhibition in the stimulated cortical region. Measures of CSP have been shown to be reliable in repeated measures studies to determine an effect of intervention within a group of subjects (Orth and Rothwell 2004; Borich et al., 2009). Values are calculated as the value recorded at the latest time minus the earliest time point. | Baseline and Day 5 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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writer's cramp, clinical, focal hand dystonia, rehabilitation, rTMS