Brain Changes in Patients With Focal Hand Dystonia

Focal Dystonia Clinical Trial

Official title: Evaluation of Density and Pattern of Distribution of GABA A Receptors in the Brain of Patients With Focal Hand Dystonia Studied With PET Using [11C] Flumazenil

Status Completed

Clinical Trial Summary

This study will examine how chemical changes in the brain produce symptoms of hand dystonia. Patients with dystonia have muscle spasms that cause uncontrolled twisting and repetitive movement or abnormal postures. In focal dystonia, just one part of the body, such as the hand, neck or face, is involved. The study will use positron emission tomography (PET) to find our which areas of the brain in patients with focal hand dystonia differ from healthy volunteers without focal hand dystonia.

Healthy volunteers and patients with focal hand dystonia between 18 and 65 years of age may be eligible for this study. Candidates are screened with a medical history and physical and neurological examinations.

Participants undergo the following procedures:

• PET scanning: The PET scanner is shaped like a doughnut. The subject lies on a bed that can slide in and out of the scanner. A custom-molded plastic mask is placed on the face and head to support the head and prevent it from moving during scanning. Two radioactive substances - five doses (one per scan) of [15 O] water and one dose of [11C] flumazil are injected into the body through a vein. The dose of injected radioactive substance is very small, and they are not harmful to the body. The [15 O] water doses are injected during the first hour and scans are taken every 10 minutes. The [11C] flumazil is injected during the second hour. The radioactive substances are detected by the PET scanner and provide information on the functioning of the brain chemistry.

• MRI scanning: MRI uses a magnetic field and radio waves to produce images of body tissues and organs. The patient lies on a table that is moved into the scanner (a narrow cylinder), wearing earplugs to muffle loud knocking and thumping sounds that occur during the scanning process. Scanning time for this study will be less than one hour. Subjects may be asked to lie still for up to 10 minutes at a time.

Clinical Trial Description

Objective

The purpose of this study is to determine if in focal hand dystonia there is disinhibition involving key structures of the motor control system (basal ganglia, thalamus, cerebellum and motor cortex) caused by dysfunction of the GABA-ergic neurons. The major inhibitory neurotransmitter in the central nervous system is gamma-amino butyric acid (GABA), which acts mainly through GABA A receptors, the majority of which possess the benzodiazepine binding site. Pathological processes involving GABA-ergic neurons will cause alterations in the density of GABA receptors, which can be visualized and measured with positron emission tomography (PET) using as a radioactive ligand [(11)C] Flumazenil.

Study Population

This research will be conducted using 20 patients with primary focal hand dystonia and 20 healthy volunteers that are matched by age and gender.

Design

By using positron emission tomography (PET) using radioactive ligand [(11)C] Flumazenil, we will detect alterations in the density of GABA receptors in patients with primary focal hand dystonia in comparison with control subjects.

Outcome Measures

We will be able to determine the density of GABA A receptors of the various Regions of Interest as measured by PET analysis among these groups of subjects. This study should provide new information concerning localization and degree of dysfunction of GABA-ergic neurons in movement related structures in dystonia, which might open new possibilities for pharmacological treatment of this disorder. ;

Related Conditions & MeSH terms

• Dystonia
• Dystonic Disorders
• Focal Dystonia

• NCT number: NCT00306865
• Study type: Observational
• Source: National Institutes of Health Clinical Center (CC)
• Status: Completed
• Phase: N/A
• Start date: March 17, 2006
• Completion date: October 14, 2010