J Korean Neurol Assoc.
1999 Jul;17(4):528-533.
Clinical Features of Essential Tremor
- Affiliations
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- 1Department of Neurology, Dong-A University College of Medicine.
Abstract
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BACKGROUND: Essential tremor is one of the most common types of movement disorders. Although it is sometimes prefaced with the term 'benign', it often causes significant disabilities. Clinical characteristics and responses to various drugs have not been investigated systematically in Korea. Therefore, we studied the clinical features, electrophysiologic findings, and drug responsiveness of essential tremor.
METHODS
Forty-five patients were included in the study by clinical criteria for essential tremor. We investigated their clinical features including tremor type, involved sites, family history, and responsiveness to alcohol. We used an electromyography study to evaluate the contraction patterns between agonist and antagonist muscles and the frequency of tremor. Primidone and propranolol were prescribed to all the patients (N=30) with a sufficient washout period (more than 2weeks) for drug responsiveness. Drug responsiveness was estimat-ed with self-assessment scales.
RESULTS
The mean age of patients at the onset of the tremor was 45 years and the average duration of the tremor was 11.1 years. Kinetic tremor was dominant in 17 patients (37.8%) and postural tremor in 28 patients (62.2%). Family history was found in 18 patients (40%) and alcohol reduced tremors in 18 (64.8%) out of 28 patients with sufficient alcohol intake. Co-contraction was seen in 18 patients (40%), alternative contraction in 15 (33.6%), and mixed contraction in 3 (6.7%). Mean frequency was 6.7 Hz. Propranolol reduced tremor in 24 patients (80%), and primidone in 27 patients (90%).
CONCLUSIONS
It was concluded that essential tremor was heterogenous clinically and electrophysiologically. Primidone was found more effective than propranolol in reducing tremor.
