Age-associated memory impairment. Normal aging or warning of dementia?
Aging causes deterioration in various aspects of memory performance in healthy adults. Different diagnostic classifications have been proposed for use in the characterisation of mild cognitive disorders associated with aging. One of the best established of these classifications is age-associated memory impairment (AAMI). Epidemiological data suggest that AAMI is a phenomenon of normal aging rather than a sign of progression from normal aging to a pathological state such as Alzheimer's disease. A number of studies that have combined neuropsychological, neuroradiological and neurophysiological data have provided evidence of distinct characteristics in individuals with AAMI. At present, however, AAMI does not appear to describe any homogeneous group of individuals. Moreover, the neuropsychological methods used to diagnose AAMI appear to be ambiguous. Thus, AAMI appears to occur in a highly heterogeneous group of individuals, and is of questionable clinical or theoretical significance. More reliable diagnostic approaches are needed for use in studies that are attempting to identify the risk factors for dementia or to find a treatment for very early dementia.