Prevalence of a history of shaking in persons 65 years of age and older: diagnostic and functional correlates.

The purpose of this study was to determine the prevalence and functional and diagnostic correlates of reported shaking in the community-dwelling elderly. We conducted a standardized neurological evaluation of 1,056 nondemented Medicare recipients in Washington Heights-Inwood, Northern Manhattan (New York). Of 1,056 patients, 108 reported shaking (10.2%). The prevalence of reported shaking did not increase with age. It did differ between ethnic groups, but when adjusted for depression and score on the Schwab and England Activities of Daily Living (ADL) scale, this difference was insignificant. The age-adjusted prevalence was similar for women and men. Neurological examination of the 108 who reported shaking showed that 8.3% had tremor at rest, 17.6% had tremor with action, 5.6% had dyskinesia or chorea, and an additional 28.7% had various problems in coordination or movement. The remaining 39.8% had neither tremor nor problems in coordination or movement. Only 2.9% of individuals with reported shaking had Parkinson's disease (PD), 8.7% had essential tremor, and 2.1% had oral-buccal-lingual dyskinesia. Of the remaining 86.3%, 29 (31%) had no identifiable medical condition. Those who reported shaking were less independent with ADLs, regardless of presence of tremor on examination. Shaking is commonly reported by the community-dwelling elderly. It does not necessarily identify individuals with essential tremor and PD, and is related to decreased independence in ADLs.