What matters in semantic feature processing for persons with stroke-aphasia: Evidence from an auditory concept-feature verification task.

BACKGROUND: The relationship between object concept domains (living vs. nonliving) and their underlying feature structures is a frequent area of investigation regarding semantic processing in healthy individuals and some individuals with neuropsychological impairment resulting from herpes simplex encephalitis, semantic dementia and Alzheimer's disease. However, this relationship has been less well-investigated in persons with stroke-aphasia (PWA), even though many treatments for anomia following stroke are predicated on the use of semantic feature cues. AIMS: As part of a larger investigation into the influence of semantic feature processing on naming for PWA, this study examined the ability of PWA to confirm the relations between object concepts and associated semantic features. METHODS & PROCEDURES: 15 native English-speaking, right handed individuals with post-stroke-aphasia responded yes or no via button press to feature-verification questions designed to probe the relationships between concept domain and feature type and distinctiveness. OUTCOMES &
RESULTS: PWA were more accurate and quicker to confirm concept-feature relationships when features contained function/action, rather than visual-perceptual, information about concepts and when features were distinctive to concepts rather than shared. The truthfulness (i.e., veracity) of concept-feature pairings was demonstrated to differentially affect living versus nonliving concepts. Within domain, only nonliving concepts were verified more accurately and more quickly when pairings were true (rather than false). Between domains, true nonliving concept-feature pairings were more accurately and more quickly verified than true living concept-feature pairings. Also with respect to veracity, correlations were observed between aphasia severity and accuracy and speed of response to false concept-feature pairings.
CONCLUSIONS: Findings have implications for the way in which semantic processing is probed with PWA, as well as providing preliminary information regarding responsivity of PWA to differing types of semantic information for living versus nonliving concepts. The fact that PWA demonstrated disproportionate difficulty responding to certain types of semantic information also suggests preliminary implications for the utility of different types of semantic cues in semantically-based treatments for word retrieval impairment.