Extrapyramidal Signs by Dementia Severity in Alzheimer Disease and Dementia With Lewy Bodies

Alzheimer disease (AD) and dementia with Lewy bodies (DLB) are common etiologies of dementia with overlapping clinical features. Our objective was to determine which extrapyramidal signs (EPSs) are most helpful in identifying DLB. We analyzed data from the National Alzheimer's Coordinating Center, including demographics, Unified Parkinson's Disease Rating Scale (UPDRS) scores, Mini-Mental State Examination (MMSE) scores, and clinical diagnosis. The subjects were divided into 3 groups: AD, DLB, or Lewy body variant (LBV). The UPDRS motor scores were totaled and analyzed within and across the MMSE strata using regression techniques. Further, we divided UPDRS subscores into 9 EPSs, dichotomized as either present or absent. Logistic regression analysis was used to compare each of the EPS in the AD and Lewy body (DLB+LBV) groups. DLB subjects (n=130) were more likely to be male individuals, younger, and have higher MMSE scores (P<0.001) compared with that in AD (n=1826) or LBV (n=105) subjects. Differences were found for total UPDRS score and number of EPSs (P<0.001), after controlling for age, sex, and MMSE. Logistic regression models demonstrated that masked facies best differentiated AD from Lewy body (odds ratio=6.5, P<0.001, 95% confidence interval, 3.8-11.1). If these findings are neuropathologically validated, then the presence of specific EPS may help clinicians better differentiate AD and DLB.