Microstructure and fluency in TBI discourse (Lundine & Barron, 2019)

Abstract

Purpose: The purpose of this exploratory study was to identify specific microstructural and fluency differences in expository and narrative summaries produced by students with a traumatic brain injury (TBI) compared to students with typical development (TD).Method: Five adolescents with TBI and 5 matched peers with TD verbally summarized 1 narrative and 2 expository (compare–contrast, cause–effect) lectures, creating 30 summaries. Researchers transcribed summaries and used paired t tests to analyze between-group differences in microstructural measures (productivity, lexical diversity, syntactic complexity), mazing behaviors, and pausing patterns.Results: Youth with TBI produced significantly fewer utterances than teens with TD in both expository contexts, whereas youth with TD produced a significantly greater mean length of C-unit than teens with TBI in the narrative summary only. Youth with TBI produced significantly fewer filled pauses per utterance than did youth with TD during the cause–effect summary only and significantly more pauses per utterance and within-clause pauses per utterance during the compare–contrast summary. Where findings were statistically significant, effect sizes were large. There were no statistically significant between-group differences in mazing or pausing behaviors during narrative summary production.Conclusions: This study is the 1st to compare microstructural and fluency characteristics in teens with TBI and those without when producing verbal summaries of a narrative and 2 types of expository passages. Findings from this study reinforce the need to expand research focusing on expository discourse tasks and identify variables that may be prone to disruption following TBI. Future work is needed to confirm whether identified differences correspond to true discourse difficulties.Supplemental Material S1. Summary and description of lecture stimuli.Supplemental Material S2. Pause & maze coding/counting instructions (adapted from Peach, 2013). Supplemental Material S3. Examples of compare–contrast summaries for included participants (mazes and abandoned/unanalyzed utterances removed). Supplemental Material S4. Participant-level data for outcome variables (bolding indicates statistically significant differences between groups). Lundine, J. P., & Barron, H. D. (2019). Microstructural and fluency characteristics of narrative and expository discourse in adolescents with traumatic brain injury. American Journal of Speech-Language Pathology, 28(4), 1638–1648. https://doi.org/10.1044/2019_AJSLP-19-0012