The production of discourse by patients with right hemisphere-damage (RHD) will be analyzed to assess the relationship between discourse production and attentional capacity in patients with primarily anterior or posterior lesions. Ten subjects with primarily anterior and ten with primarily posterior atherothrombotic brain infarction in the right hemisphere, and ten matched control subjects will participate. Lesion location will be determined from brain CT scans given at a uniform time from stroke onset. Expository, narrative, and procedural discourse will be elicited through four tasks that are randomly administered to control for practice and fatigue effects. Responses will be tape recorded, transcribed verbatim, and analyzed for informational content and cohesion. The informational content analysis will include measures of the ability to convey essential, elaborative, irrelevant, redundant, off-topic and incorrect information. Additional measures will include rate of speech (words per minute) and a communicative efficiency index derived from the ratio of number of essential units to the total number of works produced. The cohesion analysis will include measures of structural cohesion (filler words and phrases), and reference (pronouns without referents, indefinite words, deictic terms). Attentional capacity will be determined by performance on standardized tests designed to assess attentional skills and unilateral visual neglect. Multivariate analyses with planned comparisons will be applied to the informational content variables, to the cohesion variables, and to the attentional test battery scores to compare the primarily anterior and posterior RHD groups and to contrast the pooled data obtained from these two groups with that of the control subjects. Pearson-product moment correlations will be conducted between the discourse variables and the scores obtained on the attentional tasks. Data also will be analyzed to identify task differences that affect discourse production. It is hypothesized that the subjects with posterior right hemisphere dysfunction will perform more poorly on the discourse tasks than the patients with anterior lesions, and the discourse performance will correlate with attentional test scores.
