Semantic priming in anomic aphasia: a focused investigation using cross-modal methodology

Background: Semantic priming in individuals with anomic aphasia has never been the primary focus of an investigation. To date, one study investigated the effects of semantic priming in individuals with fluent aphasia (including anomic aphasia), revealing an inconsistency in semantic priming in the anomic group. Parallels from Broca's aphasia and Wernicke's aphasia literature may be drawn. However, due to the heterogeneity of anomic aphasia, a focused investigation was necessary. Aims: Semantic priming effects were investigated using a cross-modal pairwise paradigm. It was hypothesised that participants with anomic aphasia would demonstrate priming patterns at a stimulus onset asynchrony (SOA) of 500ms with slower overall reaction times (RTs) than the control participants. It was further hypothesised that the participants with anomic aphasia might show less inhibition effects than the control participants. Methods & Procedures: Participants with anomic aphasia (n=11) and healthy control participants (n=16) completed a lexical decision task where prime-target pairs were present in equal proportions (related, unrelated, and nonwords). A neutral prime condition was also incorporated. Using a cross-modal pairwise paradigm, participants heard a spoken word 500ms later, a written word appeared on screen (for 4000ms). Participants were required to make a decision as to whether the written word was real, and RTs were recorded. Outcomes & Results: Linear mixed model analysis was undertaken and revealed no significant two-way interaction effect, indicating both groups showed priming patterns. A main effect of group was evident, showing faster RTs by the control participant group, confirming our hypothesis that people with anomic aphasia primed at an SOA of 500ms in a similar manner to the control participants, with slower RTs. Conclusions: Semantic priming effects were present in anomic aphasia at relatively short SOAs and may be contributed to by automatic processes. Several parameters are proposed that should be adopted for further investigation into semantic priming in anomic aphasia including electrophysiological measures and manipulation of SOAs and relatedness proportions (RPs) to more precisely measure the effects of controlled versus automatic processes. Such investigation has the potential to inform new assessment and management techniques.