Physiologic Studies of Spasticity
Condition: Muscle Spasticity; Healthy
MeSH terms: Muscle Spasticity
Study type: Observational

Summary: 
      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.
    

Detailed description: 
      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.
    

Keywords: Pyramidal Tract; Primary Lateral Sclerosis; Spastic Paraparesis; EMG; Magnetic Stimulation; Muscle Spasticity; Healthy Volunteer