Brain Anatomy in Dystonia

Overview

This study will use high-resolution magnetic resonance imaging (MRI) to look for subtle differences in brain anatomy between patients with focal hand dystonia (also called writer s cramp) and healthy normal volunteers. Patients with hand dystonia have prolonged muscle contractions that cause sustained twisting movements and abnormal postures. These abnormal movements often occur with activities such as writing, typing, playing certain musical instruments such as guitar or piano, or playing golf or darts. Patients with focal hand dystonia and healthy volunteers will be enrolled in this study. Patients will be recruited from NINDS s database of patients with focal hand dystonia. Volunteers will be selected to match the patients in age, sex and handedness. This study involves two visits to the NIH Clinical Center. The first visit is a screening visit, in which patients and volunteers will have a medical history, physical examination, neurological examination, and assessment of handedness. Women of childbearing age will be screened with a pregnancy test. Pregnant women are exclude from this study. Those who join the study will return for a second visit for magnetic resonance imaging. MRI uses a magnetic field and radio waves to produce images of the brain. For the procedure, the participant lies still on a stretcher that is moved into the scanner (a narrow cylinder containing the magnet). Earplugs are worn to muffle loud noises caused by electrical switching of radio frequency circuits used in the scanning process. The scan will last about 45 to 60 minutes, at most. Some volunteers may be asked to return for a third visit to obtain a second MRI on a different scanner.

Objective The term, dystonia, is used to describe a syndrome characterized by prolonged muscle contractions causing sustained twisting movements and abnormal postures of the affected body part(s). Although no structural brain abnormalities have been definitively demonstrated in the visual inspection of MRI scans from patients with primary focal dystonia, there are several lines of evidence for subtle structural brain abnormalities at both the subcortical and cortical levels. We hypothesize that those abnormalities might be detected by using appropriate acquisition and analysis methods. Study population This research will be conducted using patients with primary focal dystonia and normal volunteers. Design By using high-resolution 3D structural magnetic resonance imaging (MRI) of the brain and voxel-based morphometry (VBM), and diffusion tensor imaging (DTI) at 3 Tesla and high resolution anatomical images at 7 Tesla, we will detect structural changes in patients with primary focal dystonia in comparison with control subjects. VBM and DTI are methods implemented in the statistical parametric mapping software (SPM2). Magnetic resonance spectroscopy (MRS) will use special software to calculate gamma-aminobutyric acid (GABA) levels in a region of interest. Outcome measures VBM and DTI analysis in SPM2 will enable us to make a voxel-wise comparison of local concentration/volume of gray/white matter among these groups of subjects. This study can lead to an improved knowledge of the pathophysiology of primary hand dystonia can help to elucidate dystonia s pathogenesis/etiology and may lead to specific preventative or therapeutic approaches. The MRS study will enable us to study GABA levels in the sensory motor cortices, prefrontal cortex and basal ganglia in primary dystonia patients and normal subjects.