Studying Childhood-Onset Hemidystonia
Condition: Dystonia; Cerebral Palsy
MeSH terms: Cerebral Palsy; Dystonia
Study type: Observational

Summary: 
      Background:

      - Childhood-onset dystonia is caused by a brain injury. It causes muscle contractions and
      twisting movements that the person with dystonia cannot control. The term hemidystonia is
      used when only one side of the body is affected. When dystonia starts during childhood, the
      brain and nerves may not develop normally. People with hemidystonia can become disabled
      because of the unwanted postures and twisting that dystonia causes. More research is needed
      to determine how dystonia affects brain development.

      Objectives:

      - To study brain function in people with hemidystonia.

      Eligibility:

        -  Individuals between 18 and 40 years of age who developed hemidystonia before age 13.
           Only one wrist may be affected by hemidystonia, and participants must have at least some
           movement in that wrist.

        -  Healthy volunteers at least 18 years of age.

      Design:

        -  This study requires five visits to the NIH Clinical Center: a screening visit and four
           study visits. Each visit will last up to 3 hours. Visits will be scheduled about once a
           week. The study procedures may be done in any order.

        -  Participants will be screened with a physical exam and medical history.

        -  Participants will have the following tests:

        -  Brain magnetic resonance imaging scan. During the scan, participants will be asked to
           move their hand at the wrist when they hear a tone.

        -  Motor tests of arm movement, balance, and walking. These tests may also examine nerve
           development and muscle tone.

        -  Two transcranial magnetic stimulation sessions to study the electrical activity of the
           muscles and brain. These sessions may also involve sensory tests. Participants will have
           hearing tests before the first session and after the second session.

        -  No treatment for hemidystonia will be provided as part of this study.
    

Detailed description: 
      Objective

      In childhood-onset hemidystonia, motor and sensory abnormalities pose a great challenge to
      voluntary movement. In an effort to inform future methods of treatment of this disorder, this
      study seeks to (1) characterize involuntary muscle activity, (2) explore neurophysiologic
      mechanisms of involuntary muscle activity, (3) characterize abnormalities of sensation, (4)
      assess performance on two sensorimotor tasks (voluntary postural control, and a
      reach-to-grasp arm movement), and (5) explore brain abnormalities using imaging in
      childhood-onset hemidystonia.

      Study Population

      The dystonia group will consist of 40 individuals (age 7-40 years) with childhood-onset
      hemidystonia. The control group will consist of 40 individuals within the same age range with
      no neurological disorders.

      Design

      This is a cross-sectional study, in which multiple assessments will be performed over a short
      period. Results in the dystonia group will be compared to results in the control group. Due
      to the laterality of brain injury in hemidystonia, outcomes from both arms and cortical
      hemispheres will be compared to each other. Outcomes within the dystonia group will be
      correlated with validated dystonia rating scales as well as with the age at the time of
      injury.

      Outcome Measures

      In Objective 1, we will analyze the timing of involuntary electromyographic (EMG) activity
      and kinematics triggered in the dystonic arm during various tasks. In Objective 2, we will
      investigate various types of intracortical inhibition (short intracortical inhibition, long
      intracortical inhibition, contralateral silent period, and ipsilateral silent period) and
      intracortical facilitation in motor cortical regions controlling the dystonic wrist flexor
      during voluntary contraction of the wrist extensor using transcranial magnetic stimulation
      (TMS). In addition, we will perform a coherence analysis between EMG activity in the wrist
      flexor and extensor muscles and between electroencephalographic (EEG) activity in the primary
      motor cortex and the contralateral wrist muscles. In Objective 3, we will test tactile sense
      (spatial and temporal), vibration sense, and stereognosis of the hand. In Objective 4, we
      will analyze seated limits of stability (voluntary postural control), and the timing and
      amplitude of EMG activity and kinematics in the arm during a reaching and grasping arm
      movement. In Objective 5, we will obtain brain scans with structural magnetic resonance
      imaging (MRI), diffusion tensor imaging (DTI), resting state functional connectivity MRI, and
      functional MRI during a simple task.
    

Observational model: Case-Control
Time perspective: Prospective
Keywords: Neurophysiology; Hemidystonia; Childhood-onset; Motion Analysis; Neuroimaging; Childhood Onset Hemidystonia; Healthy Volunteer; HV