Occurrence of resting tremor in Parkinson's disease.

Several previous studies have noted that resting tremor (RT) is absent in 10% to 30% of idiopathic Parkinson's disease (IPD) patients. We report our 22-year observations in 47 pathologically verified parkinsonian patients. In all the IPD cases with median follow-up of 3.7 years, RT was noted on at least one evaluation. Among other parkinsonian syndrome variants characterized by widespread subcortical pathology with median follow-up of 2.86 years, RT was seen in 31% of the cases. Our data indicate that the sites typically involved in IPD are sufficient to produce RT.