The Effects of Repetitive Paired Associative Stimulation in Dystonia

Dystonia Clinical Trial

Official title: Investigating the Plastic Effects of Repetitive Paired Associative Stimulation (rPAS) in Dystonia

Status Completed

Clinical Trial Summary

Background:

• People with dystonia have serious muscle contractions that cause abnormal movements or postures. This significantly affects their daily lives. The common type is called organic. The other type is psychogenic. People with this type have typical symptoms plus some psychological effects. Researchers will look at how rapid transcranial magnetic stimulation (rTMS) of the brain combined with stimulation of a nerve affects the ability to detect sensations. They will compare the responses of people with different types of dystonia. They will also compare the responses of people with dystonia to responses of people without it. This study may help us learn more about the nature of different types of dystonia.

Objectives:

• To see whether TMS combined with nerve stimulation affects the brain differently in people with different types of dystonia and those without dystonia.

Eligibility:

• Individuals at least 18 years old, who are right-handed and have dystonia.

• Healthy volunteers at least 18 years old.

Design:

• Participants will have two clinical visits. Each visit will be a few hours long. They can be done on the same day.

• Participants will be screened with a medical history and physical exam.

• Participants will take several sensory tests. For these tests, electrodes will be placed on their skin. The participants will feel small electric shocks during some of the tests.

• Participants will undergo TMS. For 2 minutes, quick electrical currents will pass through a wire coil placed on their head. As this happens, researchers will ask the participants to move certain muscles.

Clinical Trial Description

Objective:

To investigate the effects of pairing brain and peripheral nerve stimulation in organic and psychogenic dystonia to see if this technique can differentiate them.

Study Population:

We intend to do an internal pilot study of 6 patients with organic dystonia, 6 patients with clinically definite psychogenic dystonia and 6 age-matched healthy volunteers. We will then perform an analysis to see how many subjects we need to prove or disprove a difference between groups.

Design:

Subjects will have a baseline screening visit, electromyography (EMG) and nerve stimulation, sensory threshold testing, and measurements of brain excitability using motor evoked potentials (MEPs) from transcranial magnetic stimulation (TMS). They will then undergo rapid TMS repetitively paired with stimulation of a nerve in the arm. Outcome variables will again be measured immediately after (T0), 30 minutes (T30) after, and 60 minutes (T60) after the end of brain stimulation.

Outcome Measures

Primary outcome variable: Change in MEP amplitudes at T30 from baseline

Secondary outcome variables:

• Input-output curve parameters (measured at baseline, T0, T30, and T60)

• Temporal discrimination threshold (TDT)

Exploratory Measures

• Short interval intracortical inhibition (SICI), a measure of inhibition in the motor cortex

• Influence of Val66Met BDNF polymorphism on the output variables

Repeated measures analyses of variance (ANOVA) will be used to investigate the following three factors on the outcome variables: time (four levels: baseline, T0, T30 and T60) and muscle (two levels: APB and FDI) as within-subject factor and group (three levels: organic dystonia, psychogenic dystonia, and healthy controls) as between-subjects factor. The model of repeated measures ANOVA will include the interactions between the three factors. If the interaction between muscle and group is significant, the interaction between time and group will be evaluated for each muscle separately. If significance is found for time and/or group, then the evaluation will be followed by Tukey Kramer multiple pair-wise comparisons. ;

Related Conditions & MeSH terms

• Dystonia
• Dystonic Disorders

• NCT number: NCT01888926
• Study type: Observational
• Source: National Institutes of Health Clinical Center (CC)
• Status: Completed
• Phase: N/A
• Start date: June 18, 2013
• Completion date: August 2, 2016