Contextual influences on auditory comprehension of reversible passive sentences in aphasia

Stimuli reported by Hough et al. (1989) were employed to assess aphasic subjects' auditory comprehension of reversible passive sentences presented in isolation, and at the ends of narrative paragraphs that either strongly predicted or did not predict the specific subject-object relationships portrayed in the target sentences. Verbal stimuli were presented under two pictorial conditions, wherein pictured response choices were exposed either before or after presentation of the auditory stimuli. Results indicated no significant effect of pictorial condition; however, a significant advantage was observed for sentences following predictive paragraphs. Absence of a facilitative effect for non-predictive paragraphs disagreed with previous findings of Hough et al. (1989). Retrospective analysis of the combined data from the present and previous studies demonstrated that contextual facilitation for both types of paragraphs increased as a positive function of stage of recovery from aphasia. Subjects in the early stage of recovery (< 1 month) demonstrated no advantage for predictive or non-predictive narratives; subjects in the intermediate stage of recovery (1-6 months) demonstrated an advantage only for predictive narratives; and chronically aphasic subjects (>6 months) exhibited facilitative effects of both predictive and non-predictive narrative contexts. Findings are interpreted in light of semantic memory and resource allocation theories.