Pathophysiology of Focal Hand Dystonia

Dystonia Clinical Trial

Official title: Investigations of Pathophysiology of Focal Hand Dystonia

Status Completed

Clinical Trial Summary

Background:

Little is known about the problems in brain function in focal hand dystonia (FHD) or complex regional pain syndrome (CRPS) dystonia. It is unclear why some CRPS patients develop dystonia but others do not. Researchers want to learn which area of the brain is involved in CRPS dystonia compared with FHD.

Objectives:

To understand why people with CRPS develop dystonia, and if these reasons are different in people with FHD.

Eligibility:

Adults ages 18 - 70 with CRPS dystonia OR with CRPS without dystonia OR with FHD and Healthy volunteers of similar age.

Design:

Participants will be screened with physical exam, neurological exam, and medical history. They may give a urine sample and will answer questions.

Participants can have 4 - 5 outpatient visits or stay at the clinical center for approximately 5-6 days.

Participants will have MRI scans. They will lie on a table that slides in and out of a scanner that takes pictures of their brain. They will do small tasks or be asked to imagine things during the scanning.

Participants will have transcranial magnetic stimulation (TMS) sessions for a few hours, with breaks. A brief electrical current passing through a well insulated wire coil on the scalp creates a magnetic pulse. This affects brain activity. Participants may do small tasks during TMS.

Participants will have the electrical activity of their muscles measured during TMS sessions. Small sticky pads will be attached to their hands and arms.

Participants ability to feel 2 separate stimuli as different will be tested by using a weak electrical shock to their fingers. They will also be asked to feel small plastic domes with ridges, that may cause discomfort.

Clinical Trial Description

Objective: detailed evaluation of pathophysiology of Focal Hand Dystonia (FHD) with focus on the involvement of the parietal area, and to investigate differences in cortical mapping in the sensory and motor cortices between FHD and healthy volunteers.

Study population: The study will enroll patients with FHD and Healthy Volunteers (HVs).

Design: Prospective study using MRI and Physiology experiments using EMG and TMS based protocols to evaluate the differences between the groups.

Outcome measures: The evaluation using fMRI will be performed under 3 conditions; 1. Rest 2. Voluntary activity 3. Motor imagery task.

Outcome measures (fMRI based):

We will explore the differences in BOLD signal in the parietal lobe, in FHD compared to HVs, in the different conditions. We will look for changes in the BOLD signal in the parietal sensorimotor integration area.

We will use vascular occupancy imaging (VASO) to explore differences of detailed cortical mapping of neural structures between FHD and healthy volunteers.

The Physiology experiments aim to explore abnormalities and differences in the baseline motor cortical excitability between the groups and evaluate the influence of continuous Theta Burst Stimulation (cTBS) on these measures. We will study the influence of cTBS on the phenomenon Cortical Silent Period (cSP) in FHD.

We will also be studying the baseline Spatial and Temporal Discrimination (SDTs and TDTs), which are measures of sensory surround inhibition and have been noted to be endophenotypic of dystonia.

Physiology outcomes:

Baseline differential influences of PMv and IPL on motor cortical excitability and changes after cTBS of dIPL.

Baseline cortical Silent Period (cSP) in the involved and uninvolved limb in FHD and the influence of cTBS on cSP in the involved limb.

The TDTs/ SDTs in both the involved and uninvolved limbs in FHD compared to HVs. ;

Related Conditions & MeSH terms

• Dystonia
• Dystonic Disorders

• NCT number: NCT03223623
• Study type: Interventional
• Source: National Institutes of Health Clinical Center (CC)
• Status: Completed
• Phase: N/A
• Start date: December 12, 2017
• Completion date: May 18, 2022