Executive Decline and Dysfunction Precedes Declines in Memory: The Women's Health and Aging Study II

Background Understanding preclinical transitions to impairment in cognitive abilities associated with risks for functional difficulty and dementia. This study characterized in the Women's Health and Aging Study (WHAS) II 9-year declines and transitions to impairment across domains of cognition.Methods The WHAS II is an observational study of initially high-functioning, community-dwelling women aged 70-80 years at baseline. Random-effects models jointly compared rates of decline, and discrete-time Cox models estimated hierarchies of incident clinical impairment on measures of psychomotor speed and executive function (EF) using the Trail Making Test and in immediate and delayed verbal recall using the Hopkins Verbal Learning Test. Patterns of transition were related to incidence of global cognitive impairment on the Mini-Mental State Exam (MMSE).Results Mean decline and impairment occurred first in EF and preceded declines in memory by about 3 years. Thereafter, memory decline was equivalent to that for EF. Over 9 years, 49% developed domain-specific impairments. Risk of incident EF impairment occurred in 37% of the sample and was often the first impairment observed (23.7%), at triple the rate for psychomotor speed (p Conclusions Executive dysfunction developed first among nearly one quarter of older women and was associated with elevated risk for global cognitive impairment. Because EF declines preceded memory declines and are important to efficient storage and retrieval EF represents an important target for interventions to prevent declines in memory and MMSE both of which are associated with progression to dementia.