Patterns of cognitive decline, conversion rates, and predictive validity for 3 models of MCI

Our objective was to compare the predictive ability of different models of mild cognitive impairment (MCI) as a marker of incipient dementia in a longitudinal population-based Canadian sample. We examined the use of existing, well-documented MCI criteria using data from persons who underwent a clinical examination in the second wave of the Canadian Study of Health and Aging (CSHA). Demographic characteristics, average neuropsychological test performance, and sample frequencies and conversion rates were calculated for each classification. Receiver operating characteristic (ROC) analyses were employed to assess the predictive power of each cognitive classification. The highest sample frequencies and conversion rates were associated with case definitions of multiple-domain MCI. The only diagnostic criteria to significantly predict dementia 5 years later was the cognitive impairment no dementia (CIND)-2 case definition. More restrictive MCI case definitions fail to address the varying temporal increases in decline across different cognitive domains in the progression from normal cognitive functioning and dementia.