BACKGROUND: Although several investigators have been studying EMG activity in projected movment, a complete and satisfactory understanding of the EMG patterns is still lacking. This present study is an attempt to define these patterns for certain stereotyped movement in a normal population, and to investigate the electrophysiologic mechanisms of abnormal movements in extrapyramidal disorders. METHODS: 5 Patients with Parkinson's disease and 5 patients with cerebellar disease performed several different stereotyped elbow flexion tasks, and the EMG patterns from biceps and triceps were compared with control group. RESULTS: In patients with Parkinson's disease characterized, EMG pattern during a smooth felxion task was almost always abnormal and was chracterised by alternating activity in biceps and triceps. The EMG patterns during a fast flexion task were also usually abnormal although they were always composed of bursts of EMG activity of normal duration appearing alternately in the agonist and antagonist muscles. So, This study demonstrates that both slow and fast movement are clearly abnormal in these patients with diesase of the basal ganglia. In a task designed to investigate antagonist inhibition before agonist activity, a majority of the patients performed normally. CONCLUSIONS: This study suggest that, contrary to previous claims, slowness of movement is not due either to failure to relax or to rigidity of agtagonist muscles. In patients with cerebellar disease, EMG pattern during a fast flexion task showed prolongation of the initial biceps and/or triceps components, and it is suggested that this abnormality might be an elemental featrure of dysmetria. 3 of 5 patients showed the normal pattern of smooth felxion indicating that, with cerebellar deficits, smooth movements are better preserved than fast movements. The timing of the cessation of triceps activity before the initiation of biceps activity in an alternating movement was abnormal in 4 of 5 patients; this abnormality might be an elemental feature of dysdiadochokinesia.
Basal Ganglia Diseases ; Basal Ganglia* ; Cerebellar Ataxia ; Cerebellar Diseases ; Cerebellum ; Dyskinesias ; Elbow ; Humans ; Muscles ; Parkinson Disease ; Research Personnel

BACKGROUND & PURPOSE: Although several investigators have been studying EMG activities in projected movements, a complete and satisfactory understanding of the EMG patterns is still lacking. This present study is an attempt to define these patterns for certain stereotyped movements in a normal population, and to investigate the electrophysiologic mechanisms of abnormal movements in common extrapyramidal disorders. METHODS: 10 Patients with Parkinson's disease and 10 patients with cerebellar disease were tested with several different tasks, using stereotyped elbow flexions. They include fast active flexion(FAF), slow active flexion(SAF), fast passive flexion(FPF), slow passive flexion(SPF), and Antagonist-inhibition task. The recorded EMG activities from biceps(agonist) and triceps(antagonist) were analysed by being compared with normal patterns of the control group. RESULTS AND CONCLUSIONS: In most patients with Parkinson's disease, EMG patterns during some smooth flexion tasks(active and passive) were abnormal and were characterised by persistent co-contractions both in biceps and triceps. The EMG patterns during a fast flexion task(active and passive) were also abnormal in about half of all patients with Parkinson's disease. This study demonstrates that both slow and fast movements are abnormal in patients with Parkinson's disease, however slow movements are more difficult than fast movements in patients with Parkinson's disease. In a task designed to investigate antagonist inhibition before agonist activities, a majority of the patients with Parkinson's disease showed normal inhibition patterns. This study suggests that, contrary to previous claims, slowness of movement be not due to either failure to relax, or rigidity in antagonist muscles. In patients with cerebellar disease, EMG patterns during a fast flexion task showed prolongation of the initial biceps and/or triceps components, and it is suggested that this abnormality might be an elemental feature of dysmetria. All patients with cerebellar disease.
Basal Ganglia ; Basal Ganglia Diseases ; Cerebellar Ataxia ; Cerebellar Diseases* ; Cerebellum ; Dyskinesias ; Elbow ; Humans ; Muscles ; Parkinson Disease* ; Research Personnel