A clinical study of non-parkinsonian and non-cerebellar tremor at a specialty movement disorders clinic

BACKGROUND: No Indian studies have focused on the clinical aspects of tremor. AIMS: To study the distribution of various etiological types of tremor disorders at a Movement Disorders clinic of a large, tertiary care hospital in India and to study the clinical characteristics of essential tremor [ET]. SETTING AND DESIGN: Prospective cross-sectional study at a tertiary care specialty clinic. MATERIAL AND METHODS: Patients presenting with tremor as the chief complaint, with no features suggestive of parkinsonism, cerebellar disorder or acute central nervous system disorder, were included. Patients were classified into different etiological categories from detailed history. All patients diagnosed as ET, were further interrogated for a detailed family history and examined for characteristics of tremor. These patients were then classified into 'definite', 'probable' and 'possible' ET. RESULTS: One hundred and six patients (mean age 44.4 + 15.1 years) were examined during the study period. ET (59.4%) and dystonic tremor (21.7%) were the commonest types. Only 43% patients of ET reported progression; response to alcohol was seen in only a single patient, a positive family history was present in 52.4% and in 36.4% the inheritance was of an autosomal dominant pattern. CONCLUSION: ET and dystonic tremor are the commonest causes of tremor presenting to a specialty Movement Disorders clinic. Most patients with ET have high-frequency tremor, with mild asymmetry in 40% cases. Alcohol responsiveness may not be a useful tool in the diagnosis of ET.