fMRI Studies of Task Specificity in Focal Hand Dystonia
Condition: Focal Dystonia
MeSH terms: Dystonia; Dystonic Disorders
Study type: Observational

Summary: 
      This study will examine how the brain makes involuntary spasms and contractions in patients
      with focal hand dystonia (FHD). Patients with dystonia have muscle spasms that cause
      uncontrolled twisting and repetitive movement or abnormal postures. In FHD, only the hand is
      involved. The study will use functional magnetic resonance imaging (fMRI, see below) to study
      which areas of the brain are primarily affected in FHD and better understand how brain
      changes produce dystonia symptoms.

      Normal right-handed volunteers and patients with FHD who are 18-65 years of age may be
      eligible for this study. Candidates are screened with a medical history and physical and
      neurological examinations. Women who can become pregnant have a urine pregnancy test.

      All participants undergo fMRI. This test uses a strong magnetic field and radio waves to
      obtain images of body organs and tissues. The subject lies on a table that is moved into the
      scanner (a metal cylinder), wearing earplugs to muffle loud knocking and thumping sounds that
      occur during the scanning process. The procedure lasts about 90 minutes, during which time
      the patient is asked to lie still for 10-15 minutes at a time. During the procedure, subjects
      are asked to perform some tasks, including writing, tapping with their hand, and drawing in a
      zigzag motion. Each task is performed using the right hand, left hand and right foot.
    

Detailed description: 
      Objective:

      Writer's cramp, a form of focal hand dystonia, is the most frequently observed task specific
      dystonia. Symptoms of writer's cramp often appear as soon as the pen is picked up, or after a
      few words of writing. Patients with simple writer's cramp have difficulties writing, but
      carry out other tasks with the affected hand without spasms. Little is known about why the
      hand spasms when writing, while performing other tasks normally.

      The purpose of this study is to identify brain areas of activation associated specifically
      with the task of handwriting with the dystonic hand, in patients with simple writer's cramp.
      Simple writer's cramp can be defined by a patient exhibiting the symptoms only when writing
      and symptoms are not present in any other task performance. Specifically for this study,
      patients should be able to write for 20 seconds consecutively in a run. We plan to use
      functional magnetic resonance imaging (fMRI) to identify the pattern of blood oxygenation
      level-dependent (BOLD) activation in the brain when different tasks are performed by
      different limbs in healthy volunteers and patients with focal hand dystonia.

      Study Population:

      This research will be conducted using 22 patients diagnosed with simple writer's cramp and 32
      healthy volunteers matched for age and gender.

      Design:

      Using a block design in functional magnetic resonance imaging (fMRI), we will examine the
      brain activity of patients and healthy volunteers while they execute three tasks: writing,
      tapping and a zigzagging motion, with three separate limbs: the dystonic hand, the opposite
      hand, and the right foot.

      Outcome Measures:

      The changes in signal intensity of the brain activity correlated with the motor program (task
      of handwriting) and effector (dystonic hand) will be collected and analyzed.

      The findings we expect to obtain with this experiment may contribute to basic knowledge of
      the linkage between task specificity and the dystonic hand, and may provide a better
      understanding of the pathophysiology of writer's cramp.
    

Keywords: Imaging Studies; Botulinum Toxin; Writer's Cramp; Focal Hand Dystonia; FHD; Writer Cramp; Healthy Volunteer; HV