Mild cognitive impairment: focus on diagnosis.

Great interest is now devoted to elderly people with memory or other cognitive complaints who are not demented. The determination of this impairment from normality is difficult, because memory performance may decline slowly along the lifetime of the individual. On the other hand, the identification of dementia depends on the criteria used for dementia (DSM-IV or ICD-10). Furthermore, cognitive deterioration of the elderly appears to be heterogenous and may forerun not only Alzheimer's disease but also other forms of dementia. By applying a set of criteria for frontotemporal mild cognitive impairment, it was possible to identify, retrospectively, a series of patients with behavioral, affective, or speech symptoms suggestive of frontotemporal dysfunction and deficits in frontal lobe-dependent neuropsychological tests, but who have maintained activities of daily living and are not demented. These patients appear to have a high probability of progressing subsequently to dementia of the frontotemporal type. Several potential neuroprotective compounds are now being subjected to clinical trials. Should they be effective in delaying the progression to dementia, the need to detect and treat elderly people with cognitive impairment will become very important.