Transcranial Magnetic Stimulation and Electrical Stimulation of Nerves to Study Focal Dystonia

This study will use transcranial magnetic stimulation (TMS) and electrical stimulation of nerves to examine how the brain controls muscle movement in focal hand dystonia (writer's cramp). Normally, when a person moves a finger, the brain's motor cortex prevents the other fingers from moving involuntarily. Patients with focal hand dystonia have difficulty with individualized finger movements, possibly due to increased excitability of the motor cortex. Musicians, writers, typists, athletes and others whose work involves frequent repetitive movements may develop focal dystonia of the hand.

Healthy normal volunteers and patients with focal dystonia 18 years of age and older may be eligible for this study.

For the TMS procedure, subjects are seated in a comfortable chair with their hands placed on a pillow on their lap. An insulated wire coil is placed on the scalp. A brief electrical current is passed through the coil, creating a magnetic pulse that stimulates the brain. This may cause muscle, hand or arm twitching if the coil is near the part of the brain that controls movement, or it may induce twitches or transient tingling in the forearm, head or face muscles. Subjects will be asked to move a finger. Just before this movement, a brief electrical stimulation will be applied to the end of either the second or fifth finger. Metal electrodes will be taped to the skin over the muscle for computer recording of the electrical activity of the hand and arm muscles activated by the stimulation. The testing will last 2-3 hours.

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Key information

Conditions

Dystonic Disorders Central Nervous System Diseases Movement Disorders Nervous System Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

National Institutes of Health Clinical Center, 9000 Rockville Pike

Bethesda, Maryland, 20892, United States

About this study

The purpose of this study is to investigate the effect of sensory afferent input on surround inhibition in the motor cortex in dystonia. Surround inhibition is a cortical phenomenon, the function of which may be to suppress unwanted movements in surrounding muscles during voluntary actions. In support of this, a recent study showed that motor output to the little finger was reduced during self-paced, voluntary movements of the index finger, despite an increase in spinal excitability. Work has also shown that in relaxed muscles, homotopic and heterotopic peripheral stimulation results in time dependent modulation of motor cortical excitability. However, no studies have examined the relationship between volitional movement and sensory input on cortical surround inhibition, the phenomenon which we hypothesize to be defective in dystonia. The aim of this study then is to examine the changes in surround inhibition when electrical stimulation is applied to the finger being actively moved, leading to an inhibition of a surrounding finger (heterotopic inhibition), at different time intervals prior to the initiation of movement, to assess the effect of heterotopic peripheral stimulation on surround inhibition in dystonia patients compared to normal subjects.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

INCLUSION CRITERIA:

Nineteen patients age 18 and over with focal dystonia of the upper limbs (writer's cramp) will be recruited for the study.

For patients, the only selection criteria are the presence of focal hand dystonia.

Nineteen normal subjects age 18 and over will be recruited for the control group.

The controls will not have dystonia or any other neurological condition.

All subjects will sign an informed consent prior to participation in the trial.

Exclusion criteria

for the trial covering both the normal control and dystonia group will include any concurrent medical or surgical condition as well as neurological or psychiatric illnesses.

Exclusion criteria

will include any individual who is on medications with potential influence of the nervous system function (antidepressants, anxiolytics, anticonvulsants, antipsychotic, antiparkinson, hypnotics, stimulants, and antihistamines).

The exclusion criteria also include patients who have received Botulinum toxin injection within 3 months of starting the protocol.

Furthermore, any individual who has a pacemaker, an implanted medical pump, a metal plate or metal object in the skull or eye (for example, after brain surgery), or who has a history of seizure disorder will be excluded from the trial.

Sponsors and collaborators

Lead sponsor

National Institute of Neurological Disorders and Stroke (NINDS)

Nih

Registry information

Official study title

The Effect of Peripheral Heterotopic Stimulation on Cortical Excitability in Dystonia

Important dates

Study start: 2002
Study completion: 2008
First posted: Nov 20, 2002
Registry last updated: Jul 2, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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