In a community-dwelling cohort, including normal and cognitively impaired elderly men and women, advancing age is accompanied by decline in cognitive functions as measured by neuropsychological tests. This decline is slower in women and in college-educated subjects. Two cognitive indices were unaffected by education, and these may be especially useful in cross-cultural studies.

Patients with Parkinson's disease (PD) become dependent upon caregivers because motor and cognitive disabilities interfere with their ability to carry out activities of daily living (ADLs). However, PD patients display diverse motor and cognitive symptoms, and it is not yet known which are most responsible for ADL dysfunction. The purpose of this study was to identify the contributions that specific cognitive and motor functions make to ADLs. Executive functioning, in particular sequencing, was a significant independent predictor of instrumental ADLs whereas simple motor functioning was not. By contrast, simple motor functioning, but not executive functioning, was a significant independent predictor of physical ADLs. Dementia severity, as measured by the Dementia Rating Scale, was significantly correlated with instrumental but not physical ADLs. The identification of selective relationships between motor and cognitive functioning and ADLs may ultimately provide a model for evaluating the benefits and limitations of different treatments for PD.

Patients with Parkinson's disease (PD) become dependent upon caregivers because motor and cognitive disabilities interfere with their ability to carry out activities of daily living (ADLs). However, PD patients display diverse motor and cognitive symptoms, and it is not yet known which are most responsible for ADL dysfunction. The purpose of this study was to identify the contributions that specific cognitive and motor functions make to ADLs. Executive functioning, in particular sequencing, was a significant independent predictor of instrumental ADLs whereas simple motor functioning was not. By contrast, simple motor functioning, but not executive functioning, was a significant independent predictor of physical ADLs. Dementia severity, as measured by the Dementia Rating Scale, was significantly correlated with instrumental but not physical ADLs. The identification of selective relationships between motor and cognitive functioning and ADLs may ultimately provide a model for evaluating the benefits and limitations of different treatments for PD.

This study reports the sensitivity and specificity of the Clock Drawing Test (CDT) for detecting dementia of the Alzheimer type in a community-dwelling sample of elderly subjects. Forty-two patients with clinically diagnosed Alzheimer's disease and 237 cognitively intact subjects were administered the CDT as part of an epidemiological study of aging and dementia. Three individual measures of clock drawing performance (quantitative score, qualitative score, and combined quantitative and qualitative score) were determined for each participant. When qualitative elements such as errors and strategies were incorporated into the CDT score, the sensitivity was 84% and the specificity was 72%. The findings suggest that a CDT score which evaluates qualitative and quantitative features provides reasonably good discrimination between normal elderly individuals and DAT patients. However, the CDT appears to have limited utility as a single screening instrument in the community. Instruments such as the Dementia Rating Scale (Mattis, 1976) provide better discrimination of DAT, indicating that functions such as memory and verbal fluency need to be assessed during screening.