Olfaction in elderly and patients with Alzheimer's disease: Differing feedback conditions

Objective: To determine the capability of patients with Alzheimer's disease (AD) and age-matched controls to discriminate and recognize odorants equilibrated for strength and familiarity, and to determine if immediate corrective-feedback can improve performance in either task. Major results: No significant differences between elderly controls (EC) and AD patients were apparent for the discrimination task regardless of feedback condition. The EC group outperformed the AD group on the recognition task. Feedback enhanced EC group performance but failed to benefit the AD group. Conclusions: Early in the disease process, AD subjects have a deficit in processing olfactory cues at levels beyond that necessary for discrimination. This deficit is specifically related to the olfactory system and is in addition to any general cognitive deficits they may have. Feedback is ineffective for AD subjects but can greatly enhance the performance of the intact elderly on tasks requiring the verbal mediation of olfactory cues.