Impliciture Processing after Right Hemisphere Damage

Abstract

Purpose: The purpose of this study was to determine whether individuals with right hemisphere damage (RHD) process impliciture sentences differently from matched controls. The research questions were: (a) Are participants with RHD less accurate than healthy controls in impliciture sentence processing? (b) Does the introduction of story context affect impliciture processing in participants with RHD? (c) Do participants with RHD demonstrate response time profiles that differ from controls?Method: Seven participants with RHD and 16 matched controls participated in two experiments. In Experiment 1, participants listened to 144 impliciture sentences, and verbally responded with the interpretation they thought best fit what the sentence meant. In Experiment 2, participants listened to 100 stories and verbally responded with their interpretation of what the final impliciture sentence meant. There were two story types for each sentence: one that facilitated the normally preferred interpretation, and one that negated that interpretation.Results: For Experiment 1, three participants were less accurate in impliciture comprehension when compared to controls. The results were significant for lexical, possessive, quantitative, and temporal implicitures. For Experiment 2, three participants demonstrated increased accuracy with context. The results were significant for hyperbole, possessive, quantitative, and temporal implicitures. However, item analysis showed that each participant with RHD had difficulty negating the preferred interpretation of the impliciture. For the response time analysis, the control group was significantly slower in the negating compared to the facilitating context condition (F<N>profile). In contrast, participants with RHD did not demonstrate a difference (F=N profile).Conclusions: These findings suggest that reduced accuracy in impliciture processing occurs in some individuals with RHD, although additional research is needed to determine what characteristics are related to poor impliciture comprehension. Participants also were unable to use story contexts as effectively as the control group, showing difficulty negating the normally-preferred interpretation. Because response time profiles differed between participants with RHD and the control group, it is likely that the integrity of the right hemisphere is required for normal processing of impliciture and use of contextual cues. The results suggest a number of additional avenues of research in both the normally aging and RHD populations.