ABSTRACT
This chapter addresses two of the most diagnosed disorders of adulthood, aphasia, and Alzheimer’s dementia (AD), and examines how problems with semantic memory may be contributing to clinical communication problems. The chapter explores the hypothesis that what is going on in both disorders may be partially explained not only by problems with the representation of semantic information but also by problems with the allocation of attention to the concepts. It begins with a brief presentation of a Center-Surround Model (CSM) to account for the attentional selection of semantic concepts, followed by some evidence about the nature of the language disturbance in aphasia, and whether or not it can be classified as semantic. It then discusses how the CSM may be used to explain aphasic language behavior. The second addition now includes new Event-related Potentials studies, as well as updated conceptual models that explain the interplay between inward-directed attention and memory.
