Activities of daily living and global functioning.

Disability is a major negative consequence of aging, with impact on several domains of individual, familial, and social life, and a major source of expenditure for social systems. Preventing or delaying disability in the elderly depends not only on understanding the etiology of pathological processes causing disability, but also on the identification of the early stages of disability (preclinical disability). Vascular dementia may have an impact on disability with variable severity and patterns compared to nonvascular forms of dementia. Vascular cognitive impairment is consistent with a preclinical disability status in which cognitive impairment, already manifested, might not interfere substantially with everyday life activities, but might still cause subtle difficulties in selective performances, like those linked with executive functions. Instruments comprehensive and sensitive enough to describe global function in such a context should be specifically designed and validated.