Journal of the International Neuropsychological Society



Parkinsonian signs and cognitive function in old age


DEBRA A.  FLEISCHMAN  a1 a2 a3 c1 , ROBERT S.  WILSON  a1 a2 a3 , JULIA L.  BIENIAS  a1 a4 and DAVID A.  BENNETT  a1 a2
a1 Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois
a2 Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois
a3 Department of Psychology, Rush University Medical Center, Chicago, Illinois
a4 Rush Institute for Healthy Aging and Department of Internal Medicine, Rush University Medical Center, Chicago, Illinois

Article author query
fleischman da   [PubMed][Google Scholar] 
wilson rs   [PubMed][Google Scholar] 
bienias jl   [PubMed][Google Scholar] 
bennett da   [PubMed][Google Scholar] 

Abstract

Studies have shown that parkinsonian signs are related to cognitive function in aging. What remains unclear is whether this association is stronger for some cognitive domains than it is for others, and precisely how much variability in global and specific cognitive functions is explained by the motor signs. We examined the associations between four parkinsonian signs (gait, rigidity, bradykinesia, tremor) and five cognitive domains (episodic memory, semantic memory, working memory, perceptual speed, visuospatial ability) in a large cohort of older persons who were free of Parkinson's disease and dementia and were participating in the Rush Memory and Aging Project. In a series of regression equations that controlled for age, sex, and education, higher levels of three signs (gait, rigidity, and bradykinesia) were related to lower levels of cognitive function, but they accounted for less than 5% of the variance in most measures. The results did not change when the presence of depressive symptoms, diabetes, and hypertension were added to the models. The cross-sectional association between parkinsonian signs and cognitive function did not vary substantially across specific cognitive domains or specific cognitive tests. The results suggest that parkinsonian signs have a modest, but statistically reliable, association with level of cognitive function in old age. (JINS, 2005, 11, 591–597.)

(Received May 11 2004)
(Revised April 16 2005)
(Accepted April 16 2005)


Key Words: Parkinsonism; Parkinsonian signs; Aging; Cognition; Memory and Aging Project.

Correspondence:
c1 Address correspondence and reprint requests to: Debra A. Fleischman, Ph.D., Rush Alzheimer's Disease Center, Armour Academic Center Offices, 600 S. Paulina, Suite 1038, Chicago, IL. 60612. E-mail: Debra_Fleischman@rush.edu.