title: Electromyographic assessment of central motor disorders.
abstract: Experimental procedures are described that were designed to assess central motor disorders quantitatively. Initially delineated is a study of triggered ballistic movement performed in a reaction-time situation. The reciprocal triphasic EMG pattern recorded in an antagonistic muscle pair was clearly abnormal in Parkinsonian patients; increased duration, diminished synchronization of motor units, and a tendency for coactivation of agonist and antagonist muscles and for action tremor were observed. Transport time of elbow movement was prolonged, particularly in a choice reaction-time situation. Rapid, passive displacements of the forearm combined with excitability measurements of hindlimb motoneurons in monkeys revealed the existence of a transcortical loop that may contribute to increased muscle tone in Parkinsonian patients.
mesh_terms: D000818:Animals; D004576:Electromyography; D000882:Haplorhini; D006801:Humans; D009044:Motor Cortex / Q000502:physiology; D009129:Muscle Tonus; D009132:Muscles / Q000503:physiopathology*; D009420:Nervous System / Q000503:physiopathology*; D010300:Parkinson Disease / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012018:Reflex / Q000502:physiology