Improved comprehension of irony and indirect requests following a severe traumatic brain injury: two case studies

Background: Following a traumatic brain injury (TBI), people frequently have difficulty understanding nonliteral language, including irony and indirect requests. Despite the handicap that these disorders can represent in daily life, they are rarely treated clinically, and remediation studies are scarce.
Aims: The present study thus aimed to evaluate the effectiveness of an explicit metapragmatic therapy targeting nonliteral language comprehension and taking into account cognitive processes likely to underlie this comprehension (i.e., contextual processing, theory of mind, and executive functions).
Methods & Procedure: This study was registered on the ClinicalTrials.gov system (ID: NCT04708561) before participant recruitment. Two adults with severe TBI took part in the study. An ABA design with multiple baselines was used to assess the evolution of treated and non-treated written literal and nonliteral story comprehension, as well as ecological tasks and tasks assessing the cognitive processes of interest (theory of mind and executive functions). An interview was also conducted at the end of treatment to assess participant satisfaction.
Outcomes & results: Therapy resulted in significant improvement in treated items, with one-month maintenance of gains and generalisation to untreated items in both participants. The generalisation to a working memory task was also observed in one participant. Finally, participant satisfaction with the treatment was high.
Conclusions & implications: Our study demonstrated for the first time the potential of a therapy targeting irony and indirect request comprehension in TBI individuals. Clinically, it offers concrete therapeutic avenues and fills a critical gap in the TBI population’s evidence for the remediation of nonliteral language comprehension.