Finger tremor after carbon disulfide-based pesticide exposures.

Index finger tremor accompanying voluntary movement was studied in 19 age-matched control subjects and in 19 grain industry employees chronically exposed to carbon disulfide-based fumigants. Visual judgments of tremor amplitude made by neurologists during clinical examinations equaled the sensitivity of computerized tremor amplitude measurements. Tremor frequency variations detectable only with computerized measurement were present in grain workers with and without increased tremor amplitudes. Frequency differences discriminated between normal subjects and 74% of the grain workers. The distribution of tremor frequency power in the grain workers was often sequestered at 5 to 7 Hz, reminiscent of tremor in idiopathic Parkinson's disease. These findings suggest that the measurement of subtle tremor frequency changes may provide an early indication of chronic carbon disulfide poisoning.