Emotional experience and facial expression in Alzheimer's disease.

Emotional experiences and facial muscle activity of individuals with Alzheimer's Disease (AD) (n = 13) and healthy elderly control subjects (n = 21) were measured while viewing emotion-eliciting images. Alzheimer's disease and control groups rated their emotional experiences similarly and in the expected directions on dimensions of valence and arousal. Change in corrugator activity while viewing images, compared to baseline, was comparable across groups and was greatest while viewing negative images. Change in zygomatic activity, however, was significantly different between AD and control groups, with AD subjects demonstrating an inverted pattern of activity compared to controls. These findings are discussed as possible consequences of frontal cortical system involvement accompanying the disease process.