Semantic Memory and Language in Dementia of the Alzheimer Type

Abstract

Dementia of the Alzheimer Type (DAT) is a degenerative, terminal illness that has a devastating effect not only on the individual, but also on their family and friends. Current research seems to indicate that neuropsychological tests of semantic memory through object naming can be helpful in identifying those who are entering the early stages of the disease, although it is unclear whether semantic memory disintegrates or if access routes are disrupted. Few studies provide comparisons between visual and tactile object identification skills in OAT patients. Little research exists comparing the performances of healthy adult controls to DAT patients, and even fewer studies investigate the utility of a nonverbal modality of response. In order to investigate these three areas, the performance of 18 patients with DAT was compared to the performance of 21 healthy adults aged 60 and over on several tasks. A set of household objects was presented one at a time for all participants to identify visually or by touch. Control and experimental participants tried to name these objects as quickly as possible, and the number of correct recognitions were compared. Results indicated that if patients were unable to state the name of the object they were attempting to identify they benefitted from having a selection of possible names to choose from, indicating that semantic information remains. Partipants also tended to respond verbally, even when given the choice of responding nonverbally. Finally, results indicated that the DAT patients performed significantly poorer overall on tactile and visual object identification compared to controls.