Extrapyramidal signs and cognitive abilities in Alzheimer's disease

OBJECTIVE: To evaluate whether the relationship between extrapyramidal signs (EPS) and cognitive disturbances in Alzheimer's disease (AD) is influenced by illness duration. METHODS: A multivariate regression analysis was used to study the relationships between EPS, illness duration and five cognitive ability areas based on the Mattis Dementia Rating Scale (DRS) in 89 clinically diagnosed AD patients with extrapyramidal motor involvement. RESULTS: Severity of EPS was statistically associated with performance on four cognitive ability areas from the DRS including: attention, initiation and perseveration, construction and memory. Age was a significant factor related to severity of EPS. However illness duration did not contribute to the strength of the association between EPS and cognitive disturbances in patients with AD. CONCLUSIONS: The findings of the present study support the notion that while neuropsychological and motor functions often coexist in patients with AD, their relationship seems to be unrelated to degenerative processes that accumulate throughout the illness.