Emotion processing deficits may have an important effect on the quality of life of Alzheimer's disease (AD) patients and their families, yet there are few studies in this area and little is known about the cause of such deficits in AD. This study sought to determine if some AD patients have a disruption in a specific right hemisphere emotion processing system, and to determine if the processing of emotional facial expression is more vulnerable to the pathology of AD than is the perception of emotional prosody. It was specifically hypothesized that patients with greater right hemisphere dysfunction (low spatial AD patients) would be impaired on emotion processing tasks relative to those with predominantly left hemisphere dysfunction (low verbal AD patients). Both groups showed impairment on emotion processing tasks but for different reasons. The low verbal patients performed poorly on the affect processing measures because they had difficulty comprehending and/or remembering the task instructions. In contrast, low spatial AD patients have emotion processing deficits that are independent of language and/or memory and may be due to a more general visuoperceptual deficit that affects the perception of static but not dynamic affective stimuli. (JINS, 1997, 3, 411–419.)