Cognitive impairment with no dementia (CIND): Longitudinal studies, the findings, and the issues

Identification of persons at risk for developing dementia is of increasing importance as the proportion of persons over the age of 65 years grows glob ally. This review examines the neuropsychological literature specifically a ddressing the concept of impaired cognitive functioning of insufficient mag nitude to warrant a diagnosis of dementia and its meaning with respect to t he development of dementia. Although the most obvious finding in the litera ture is that persons with impaired cognitive functioning have varied outcom es, it is clear that a significant proportion of persons with mild cognitiv e impairment progress to dementia over a 1- to 2-year interval and approxim ately 50% progress to dementia by 5 years. The best and most commonly ident ified predictors of decline to dementia include age and lower baseline perf ormance on neuropsychological measures (e.g., measures of memory). In discu ssing these findings, issues related to sample definition, sample selection , and methodology are identified and recommendations for future research ar e provided.