Neuropsychological features of mild cognitive impairment and preclinical Alzheimer's disease.

Recent research has identified a transitional state between the cognitive changes of normal aging and Alzheimer's disease (AD), known as mild cognitive impairment (MCI). MCI patients experience memory loss to a greater extent than one would expect for age, yet they do not meet currently accepted criteria for clinically probable AD. An issue currently under investigation is whether MCI represents the preclinical stages of AD or a distinct and static cognitive aetiology. In an attempt to address this issue, the present investigations are adopting a convergent approach to the detection of preclinical AD, where multiple risk factors are considered when making a diagnosis. Currently, one of the most important tools when assessing early cognitive changes is neuropsychological evaluation. MCI subjects typically record neuropsychological performance between that of healthy older individuals and demented patients. Tests assessing new learning, delayed recall and attention/executive function seem to provide valuable information for screening and diagnosis of MCI and early AD if interpreted properly. Recommendations concerning methodological issues and the early management of neuropsychological MCI studies were made.