ATTENTION-DEFICIT IN ALZHEIMERS-DISEASE IS NOT SIMULATED BY AN ANTICHOLINERGIC ANTIHISTAMINERGIC DRUG AND IS DISTINCT FROM DEFICITS IN HEALTHY AGING/

Objective. To evaluate attention deficit in Alzheimer's disease (AD) a nd its relationship to attention deficits associated with aging and wi th medications altering alertness. Methods, Ten patients with probable AD, 10 healthy old controls, and 15 young controls performed a covert orienting of spatial attention task. Young controls performed the tas k an additional time after ingestion of diphenhydramine 1 mg/kg. React ion times were obtained following valid, neutral, and invalid cues. Re sults. In all groups, the reaction times were shortest for the validly cued stimuli and longest for the invalidly cued stimuli. Additionally , the AD patients performed disproportionately worse following the inv alid cue than did the control groups. Young controls given diphenhydra mine had decreased subjective alertness, performed worse than they did before drug but better than the old controls or AD patients, and had no disproportionate impairment with the invalid cue. Conclusions, AD p atients have disproportionate problems shifting spatial attention comp ared with age-matched controls. Impaired attentional performance in AD cannot be simulated in young subjects by ingestion of a combined anti histamine/anticholinergic agent at a dose sufficient to produce signif icant changes in alertness.