Attention and memory in the preclinical stage of dementia.

The aim of this study was to investigate whether attention may be specifically impaired in Alzheimer's disease from the early stages of the disease. Subgroups of patients with different types of mild cognitive impairment were selected according to standard criteria. Patients and controls were given tasks exploring various subcomponents of attention and executive functions. Only subgroups of mild cognitive impairment characterized by memory disorders obtained lower scores than controls on attention and executive tasks. On the basis of the scores obtained on the Clinical Dementia Rating at the 1-year follow-up, patients were redistributed into 2 groups: those who developed and those who did not develop dementia. Patients who presented evolution to dementia already had, at baseline, lower scores than patients who did not evolve on tasks exploring attention and executive functions. The results suggest that not only memory disorders but also attention/executive deficits may characterize dementia at the onset.