This study will examine how the brain operates during execution and control of voluntary movement and what goes wrong with these processes in disease. It will use electroencephalography (EEG) and electromyography (EMG) to compare brain function in normal subjects and in patients with focal hand dystonia. In dystonia, involuntary muscle movements, or spasms, cause uncontrolled twisting and repetitive movement or abnormal postures. Focal dystonia involves just one region of the body, such as the hand, neck or face.

EEG measures the electrical activity of the brain. The activity is recorded using wire electrodes attached to the scalp or mounted on a Lycra cap placed on the head. EMG measures electrical activity from muscles. It uses wire electrodes placed on the skin over the muscles.

Adult healthy normal volunteers and patients with focal hand dystonia may be eligible for this study. Patients will be selected from NINDS's dystonia patient database.

Participants will sit in a semi-reclining chair in a darkened room and be asked to move either their right index finger, right foot, or the angle of their mouth on the right side at a rate of one movement every 10 seconds. Brain and muscle activity will be measured during this task with EEG and EMG recordings.

Condition
Focal Dystonia

Further Study Details: 

Expected Total Enrollment:  80

Dystonia is a syndrome in which patients experience prolonged muscle contractions uncontrollably leading to abnormal body positions and sustained twisting movements due to the overflow of motor commands. This is caused by increased excitability at multiple levels of the nervous system. Physiological studies in task-related dystonia (e.g. writer's cramp) have suggested hyperexcitability of the motor cortex or a failure of intracortical inhibition due to overactive or distorted thalamocortical control. It has been speculated that in dystonia patients the loss of cortical inhibition is a result of the imbalance of the direct and indirect pathway. This deficiency in intracortical inhibition can be explained by deranged center-surround organization. In the research of the pathophysiology of dystonia, the study of possible derangement of center-surround organization at the level of the motor or sensorimotor cortex is of great interest.

It has been shown that while hand movements are associated with contralateral desynchronization of EEG (diminished power in the high alpha (micro) and beta rhythms, event-related desynchronization, ERD) over the hand representation area indicating neuronal activity in the corresponding cortex, the same area shows an increase in the same power band when the foot is moved (event-related synchronization, ERS). This might indicate diminished level of activation or "idling" state. This will be evidence for center-surround organization in the motor system if this phenomenon proves to be general. There is recent evidence suggesting that high frequency oscillations (HFOs) of the somatosensory evoked potentials (SEPs) or fields (SEFs, referred to as SEPs in this document) represent cortical inhibitory post-synaptic potentials (IPSPs). Therefore diminished HFOs would be furhter supporting evidence for decreased cortical inhibition in focal hand dystonia.

In the present study we plan to analyze EEG/MEG spectral power to assess cortical center-surround organization during voluntary movements in focal hand dystonia patients and normal subjects. We will compare the power spectral changes of beta and (micro) rhythms over the hand and face representation area using a 64-channel EEG montage associated with voluntary movement tasks involving the face or hand or foot. EMG will also be simultaneously recorded. Following recordings, EEG spectral power will be analyzed and ERD/ERS of the hand and face representation area will be measured in the two groups during the three motor tasks. Comparisons of spectral power changes will be performed between dystonics and normals as well as between affected and unaffected sides in dystonia patients. HFOs of SEPs will also be measured using EEG/MEG in normals and dystonics.

Genders Eligible for Study:  Both

Accepts Healthy Volunteers

Criteria

INCLUSION CRITERIA:
The study population will consist of (a) healthy/normal volunteers; and (b) patients with focal hand dystonia.
Normal subjects: Healthy volunteers who consented to participate in the study.
Patients diagnosed with focal hand dystonia: unilateral focal hand dystonia from our dystonia patient database who consented to participate in the study.
Both normals and FHD patients will be accrued between ages 18 to 80 years.
EXCLUSION CRITERIA:
Normal subjects: abnormal neurological exam or history of past neurological disease.
Dystonia patients: the presence of a second neurological disease or condition; abnormal neurological findings on exam that are not related to their focal hand dystonia.
For MRI studies, patients with metallic implants will be excluded to remove potential risks from this procedure.
For MRI purposes, women who are pregnant are excluded from this part of the protocol. Therefore, all women of childbearing potential will have a pregnancy test performed prior to prospective MRI studies, which must be negative, before proceeding.

Maryland
      National Institute of Neurological Disorders and Stroke (NINDS), 9000 Rockville Pike,  Bethesda,  Maryland,  20892,  United States; Recruiting

Study ID Numbers:  020010; 02-N-0010
Record last reviewed:  September 9, 2004
Last Updated:  March 2, 2005
Record first received:  October 11, 2001
ClinicalTrials.gov Identifier:  NCT00025701
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2005-04-08