Senile tremor. What is the prevalence and severity of tremor in older adults?

Background/Setting: It is well recognized that mild tremor is common among older adults, but the prevalence and clinical characteristics of this tremor have not been studied in detail. Objectives: To examine a cohort of normal older adults to: (1) ascertain the prevalence of mild test-detectible tremor; (2) quantify the severity and functional impact of this tremor, and (3) determine whether age, gender and concomitant illness predict the severity of tremor. Participants: 76 normal older adults > 55 years of age (mean age = 73.7 years). Design: Healthy older adults were identified in a community-based case-control study of essential tremor in Washington Heights-Inwood, New York. All subjects underwent a medical interview and a videotaped neurological examination. The examination included six tests: arm extension, pouring water, drinking water, using a spoon, finger-to-nose movements, and drawing spirals with each arm. Two neurologists rated the severity of tremor using a 0 to +3 clinical rating scale and a total tremor score (TTS) was calculated (range = 0-36). Forward stepwise linear regression was used to determine the association between TTS and other variables. Results: Virtually all (75 or 98.7%) showed signs of tremor (TTS > 0.5). The mean TTS = 6.3 (range = 0-14.5), corresponding to a tremor that was either mild or intermittent. Twenty-eight of 76 (36.8%) received tremor ratings of +2 (clearly oscillatory tremor of moderate amplitude and usually present) during at least one of the six tests; a tremor rating of +2 was 2.1 times more likely to occur in the nondominant than in the dominant hand. Those who were aged 57-74 years had a lower mean TTS (5.8) than those aged 75-93 (6.8), but this was not significant. Only 2 patients (2.6%) answered 'yes' to the question 'do you have uncontrollable shaking in your hands?' None was taking medication to treat tremor. Gender, ethnicity, concomitant illness (diabetes, arthritis, heart disease), and medications were not associated with a higher TTS. Conclusion: Mild but test-detectible tremor was present in almost all normal older adults, and in one-third this tremor attained a moderate amplitude during at least one activity. Characterization of this tremor would be of value to practitioners who care for older adults.