CLASSICAL-CONDITIONING IN PATIENTS WITH ALZHEIMERS-DISEASE - A MULTIDAY STUDY

Previous studies demonstrated that patients with Alzheimer's disease ( AD) do not acquire the classically conditioned eyeblink response. Thes e studies, however, were only tested over a single conditioning sessio n and, hence, raise the question of whether AD patients are capable of acquiring the response if sufficient training is given. This question may be of some importance because whether AD patients can ultimately acquire the response has implications for the underlying neurobiologic al deficit in disrupted conditioning in AD. This study tested AD patie nts and age-matched controls over 4 days. As in previous studies, AD p atients performed significantly worse than controls on Day 1, but by D ay 4, they were not significantly different from controls. Subsequent testing indicated that these effects were not due to nonassociative va riables such as changes in sensitivity to stimuli or disruption of the motor response. Also, it was reported that neither AD patients nor co ntrols showed any evidence of acquisition in an explicitly unpaired pa radigm, suggesting that neither pseudoconditioning nor sensitization i s contributory. Data are discussed in terms of the possible role of th e hippocampus in mediating conditioning deficits in AD patients.