Essential tremor: clinical, electromyographical and pharmacological studies in 146 Chinese patients.

From February 1984 to February 1988, 258 cases of various kinds of tremor were seen in our movement disorder clinic. Among them, 146 cases (57%) were diagnosed as essential tremor, and of these, 96 (65.8%) were males and 50 (34.2%) were females, ranging in age from 14 to 89 years (mean: 36 years). The main tremor occurred in the hands (100%), and in a few cases were combined with head, leg, lip, voice and neck tremors. A familial tendency was obvious in 47 cases (32%). The surface electromyographic (EMG) study of essential tremor revealed two patterns, one of synchronous type (73%) and the other of alternating type (27%). Its frequency was between 5 and 9Hz. The burst duration was short (50-100 msec) and the amplitude was low (less than 200 mu v). All cases were divided into two groups to received propranolol therapy, 78 cases with high dosages (120-240 mg/day) and 68 with low dosages (60-80 mg/day). The higher dose was better in effect than the lower one (p less than 0.01). Propranolol also had effect on tremors of alternating type (p less than 0.01), which is different from previous reports.

[Isoniazid therapy in severe cerebellar, postural and kinetic tremor].

In the routine analysis of patients with tremors, we have the routine analysis of patients with tremors, we have encountered three patients with severe cerebellar postural & kinetic tremors. Surface EMG study revealed alternating activity in antagonistic muscles with low frequency (3-5 cps) and wide duration (over 125msecs). They were different to typical essential tremor & parkinson's tremor in the clinical manifestation and tremogram. The tremor did not respond to high dose of propranolol (120-160mg/day), but responded to high dose of isoniazid (800-1200mg/day). Patients were evaluated before & after INH therapy with videotaping, surface EMG quantitative recording. One patient had transient side effects (abnormal liver function) in the beginning of treatment possibly because he was a "slow acetylator". The possible mechanism of effort of INH was discussed.