Is sentence ambiguity comprehension affected after mild traumatic brain injury? Results suggest cognitive control is more important than diagnosis.

Abstract

Individuals with mild traumatic brain injury (mTBI) may experience chronic cognitive-linguistic impairments that are difficult to evaluate with existing measures. Garden path sentences are linguistically complex sentences that lead readers down a path to an incorrect interpretation. Previous research indicates many individuals, with or without mTBI, may have difficulty fully resolving the ambiguity of garden path sentences, a skill which may require cognitive control. Evidence suggests cognitive control can be impacted by mTBI. Thus, impairments in cognitive control are expected to correlate with interpreting ambiguous sentences. To examine the relationship between cognitive control and the processing of ambiguous garden path sentences in adults with mTBI. We predict individuals with mTBI will perform more poorly on ambiguous sentence tasks compared with a control group. Further, we predict that performance on this task will correlate with measures of cognitive control and working memory. A total of 20 adults with mTBI history and 44 adults with no significant neurological history were recruited from the community. Participants completed a computerized, ambiguous sentence measure with carefully designed comprehension questions and an abbreviated neuropsychological battery of cognitive-linguistic tasks. Participants performed similarly on sentence ambiguity resolution measures across groups with a wide range in performance. A comprehension measure aimed at identifying full ambiguity resolution correlated with cognitive control across groups. A link between cognitive control and linguistic ambiguity is confirmed in a comprehension measure by the current findings. mTBI history did not appear to change the nature of the relationship between cognitive control and ambiguity resolution. High individual variability on sentence and cognitive control measures across groups suggest that if an impairment were present, it would affect both types of tasks. Thus, testing cognitive communication following mTBI should specifically examine complex cognitive and linguistic processing. What is already known on the subject Cognitive control and ambiguous sentence processing are known to be linked, but the circumstances and individual variability associated with when cognitive control is recruited to support sentence processing are not fully understood. Very little is known about sentence processing following TBI history, despite cognitive control commonly being impaired following mild TBI. Thus, our study was necessary to explore the theoretical and clinical relationships between cognitive control and ambiguous sentence processing in individuals with mild TBI history. What this paper adds to existing knowledge This study adds to our understanding of how cognitive control and ambiguous sentence processing are linked in those with mild TBI history, and similar to the few previous studies, there were no group differences in cognitive or sentence measures. The positive correlation between cognitive control on Stroop and a particular ambiguous sentence comprehension question targeting inhibitory control highlights that any relationship between abilities or assessment tasks must be very specific to tasks with overlapping requirements, such as inhibition. What are the potential or actual clinical implications of this work? The relationship between cognitive and ambiguous sentence measures highlights the need to assess all areas of cognition and communication in those with mild TBI history without assuming that impairments in cognitive performance will relate to communication. The overlap between abilities is highly specific and must be explored on a case-by-case basis in those with mild TBI. Evaluation and treatment should still be individualized based on the functional communication profile of the client.