Visual attention impairments in Alzheimer's disease

Background: Impaired attention can hinder information processing at multipl e levels and may explain aspects of functional decline in aging and dementi a. Impairments of attention in early AD may contribute to performance reduc tions in other cognitive domains, including memory and executive functions, Method: The authors analyzed the scores on a battery of tests of attention and cognitive abilities in 64 older individuals: 42 with mild AD and 22 co ntrol subjects without dementia. The authors tested the hypotheses that pat ients with AD would have impairments of visual attention, and that these im pairments would correlate with dysfunction in other key cognitive domains. Results: Patients with AD performed significantly worse than control subjec ts on measures of sustained attention, divided attention, selective attenti on, and visual processing speed. The differences were not due to difference s in age, education, or basic visual function. Strong relationships were id entified between reduced attention skills and overall cognitive impairment. Conclusions: Deterioration of attention abilities occurs in early stages o f AD, and likely contributes to functional decline in these patients. More routine assessment of visual attention deficits could give a more accurate measure of functionally useful perception in patients with AD who show norm al visual acuity and visual fields, perhaps providing useful clues to diagn osis and staging.