Physiologic Studies of Spasticity
Physiologic Studies of Spasticity
This study will provide information about changes that occur in the motor neurons of the
 spinal cord (the nerve cells that control the muscles) when the motor cortex (the region of
 the brain that controls movement) is unable to send messages to the spinal cord and muscles
 in the normal way. This information will help elucidate how the nervous system adapts after
 injury or disease of the motor cortex.

 Healthy adult volunteers and adults with a spasticity disorder and moderate weakness may be
 eligible for this study. Patients will be screened with a medical history, physical
 examination and diagnostic studies as needed. Healthy volunteers will have a neurological
 examination. Muscle weakness and spasticity will be evaluated in both groups of subjects.

 All participants will have electromyography (measurement of electrical activity in muscles)
 during nerve stimulation and transcranial magnetic stimulation, described below. (Some
 patients, such as those with a pacemaker or implanted medication pumps, metal objects in the
 eye, history of epilepsy and others, will not have magnetic stimulation.)

 Electromyography - The electrical activity of muscles will be measured either by 1) using
 metal electrodes taped to the skin overlying a muscle, or 2) using thin wires inserted into
 the muscle through a needle.

 Nerve stimulation - The nerves will be stimulated by applying a small electrical pulse
 through metal disks on the skin of the arm or leg.

 Transcranial magnetic stimulation - A brief electrical current is passed through a wire coil
 placed on the scalp. This creates a magnetic pulse, which stimulates the brain. During the
 test, the participant may be asked to tense certain muscles slightly or perform other simple
 actions.

 Nerve block - Some patients will have a nerve block of one of the nerves in the arm. For this
 procedure, a local anesthetic is injected under the skin to produce numbness and weakness in
 some arm muscles.
Objective: The purpose of this protocol is to characterize abnormalities in motoneuron
 recruitment in adult patients with corticospinal tract dysfunction using electrophysiologic
 measures. We wish to determine whether the intrinsic spinal mechanisms for recruitment are
 abnormal or whether only inputs to motoneurons are changed. This information is pertinent for
 assessing ways that can ultimately be used to enhance strength in patients with corticospinal
 tract dysfunction using the existing spinal circuitry.

 Study Design: Comparison of physiological observations in patients and age - matched control
 subjects.

 Study Population: Adults with spastic paresis aged 21-80 and healthy volunteers.

 Outcome Parameters: Measures of motor unit firing in response to peripheral nerve stimulation
 and transcranial magnetic stimulation.
-  INCLUSION CRITERIA:

 Adult patients with selective corticospinal tract dysfunction

 Minimum age 21 years; maximum age 80 years

 Moderate severity of weakness (greater than or equal to MRC Grade 4)

 Adult normal volunteers

 EXCLUSION CRITERIA:

 Severe weakness with inability to maintain voluntary contractions

 Significant sensory impairment

 For TMS studies only: pregnancy, implanted devices such as pacemakers, medication pumps or
 defibrillators, metal in the cranium except the mouth, intracardiac lines, history of
 seizures