Objective: To identify which aspects of prosody are negatively affected subsequent to right hemisphere brain damage (RHD) and to evaluate the methodological quality of the constituent studies.
Method: Twenty-one electronic databases were searched to identify articles from 1970 to February 2020 by entering keywords. Eligibility criteria for articles included a focus on adults with acquired RHD, prosody as the primary research topic, and publication in a peer-reviewed journal. A quality appraisal was conducted using a rubric adapted from Downs and Black (1998).
Results: Of the 113 articles appraised as eligible and appropriate for inclusion, 71 articles were selected to undergo data extraction for both meta-analyses of population effect size estimates and qualitative synthesis. Across all domains of prosody, the effect estimate was g = 2.51 [95% CI (1.94, 3.09), t = 8.66, p < 0.0001], based on 129 contrasts between RHD and non-brain-damaged healthy controls (NBD), indicating a significant random effects model. This effect size was driven by findings in emotional prosody, g = 2.48 [95% CI (1.76, 3.20), t = 6.88, p < 0.0001]. Overall, studies of higher quality (rpb = 0.18, p < 0.001) and higher sample size/contrast ratio (rpb = 0.25, p < 0.001) were more likely to report significant differences between RHD and NBD participants.
Conclusions: The results confirm consistent evidence for emotional prosody deficits in the RHD population. Inconsistent evidence was observed across linguistic prosody domains and pervasive methodological issues were identified across studies, regardless of their prosody focus. These findings highlight the need for more rigorous and sufficiently high-powered designs to examine prosody subsequent to RHD, particularly within the linguistic prosody domain.
Keywords: Comprehension; Emotion; Language disorders; Linguistics; Speech; Stroke.