Nerve Stimulation to Modify a Spinal Reflex

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00039819
Recruitment Status : Completed
First Posted : June 12, 2002
Last Update Posted : March 4, 2008
Information provided by:
National Institutes of Health Clinical Center (CC)

Brief Summary:

This study will determine whether stimulating the nerves or the brain can modify the spinal reflex that controls the muscles that flex and extend the ankle. Training spinal nerve networks with sensory input may provide a way of re-establishing movements, such as walking, in patients with spinal injury.

Healthy normal volunteers with no history of peripheral neuropathy or radiculopathy, ankle contractures or tendon surgery may be eligible for this study. Participants will undergo three stimulation procedures, each in a different session, to measure leg muscle reflexes. The procedures are:

  • Reflex testing - Metal electrodes are taped to the skin over the leg muscles. A small electrical pulse is delivered through the electrodes to stimulate two nerves to the muscles. This evokes a reflex between the ankle flexor and extensor muscles. The responses to several dozen stimuli are averaged.
  • Nerve stimulation - The nerve to the muscle that flexes the leg is electrically stimulated near the knee through electrodes taped to the skin. The strength of the stimulus is adjusted to produce little or no muscle movement. The stimulation is repeated every few seconds for 45 minutes.
  • Transcranial magnetic stimulation - An insulated wire coil is placed on the subject's scalp. A brief electrical current passes through the coil, creating a magnetic pulse that travels through the scalp and skull and causes small electrical currents in the outer part of the brain. There may be twitching in the muscles of the arm or leg. During the stimulation, the subject may be asked to tense certain muscles slightly or perform other simple actions to help determine the best position for the coil over the part of the brain that controls the leg. The leg is then stimulated once every 10 seconds, combined with nerve stimulation every 1 to 2 seconds.

Condition or disease

Detailed Description:
Training of spinal interneuronal networks may offer a means for re-establishing movements such as locomotion in patients with spinal injury. Sensory feedback in the pattern which results from the leg movement is hypothesized to be the critical component for training spinal networks. This protocol will address the basic assumption underlying such training: can a specific pattern of sensory input modify the strength of a spinal cord circuit? We will test whether peripheral nerve stimulation can modify the strength of the spinal reflex mediating reciprocal inhibition between ankle flexor and extensor muscles in normal subjects, comparing patterned and unpatterned stimulation.

Study Type : Observational
Enrollment : 25 participants
Official Title: Plasticity of Reciprocal Inhibition
Study Start Date : June 2002
Study Completion Date : May 2003

Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes


Healthy adult volunteers willing to participate


History of peripheral neuropathy or radiculopathy

Implanted devices, including pacemakers, pumps, and defibrillators

Ankle contractures or tendon surgery

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00039819

United States, Maryland
National Institute of Neurological Disorders and Stroke (NINDS)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Institute of Neurological Disorders and Stroke (NINDS)

Publications: Identifier: NCT00039819     History of Changes
Other Study ID Numbers: 020228
First Posted: June 12, 2002    Key Record Dates
Last Update Posted: March 4, 2008
Last Verified: May 2003

Keywords provided by National Institutes of Health Clinical Center (CC):
Spinal Cord
Sensory Stimulation
Magnetic Stimulation
Healthy Volunteer
Normal Control