J Korean Neurol Assoc.
1998 Apr;16(2):180-187.
Analysis of EMG patterns in Parkinson's disease and cerebellar diseases
- Affiliations
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- 1Department of Neurology, Chonbuk University Medical School.
- 2Department of Neurology, Kansas University Medical Center.
Abstract
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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.
