Physiologic Studies of Spasticity

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.