Expression of propositional attitudes in conversation by adults with traumatic brain injury: A relevance theoretic approach.

Background: Impairments in social communication are ubiquitous after moderate to severe traumatic brain injury (TBI). Most attempts to quantify these impairments have been descriptive rather than theoretically motivated. We propose that Relevance Theory provides a framework for characterizing social communication limitations after TBI and linking these problems to underlying cognitive impairments.

Aims: This study asked how adult speakers with and without TBI used specific linguistic forms in social communication. We selected three linguistic markers that convey thoughts and feelings of the speaker and which are intended to influence the same in the listener: propositional attitude verbs, the discourse marker like and the quotative like.

Methods & Procedures: Ten adults with moderate to severe TBI and 12 healthy adults completed 5-min casual conversations with student researcher partners as part of a larger research study. Conversations were transcribed and analysed for the frequency of the three linguistic markers, corrected for total words in the transcript.

Outcomes & Results: Participants in the TBI group used discourse marker like significantly less than participants in the healthy comparison group (0.75% and 2.06% of total words, respectively; p = 0.05, d = -0.43) and showed less variety in functions of like. The use of propositional attitude verbs and quotative like was not affected by TBI.

Conclusions & Implications: Expression of propositional attitude seems largely preserved after TBI. Relevance Theory may provide a helpful framework (1) to interpret subtle quantitative and qualitative differences that contribute to social conversation problems of adults with TBI; and (2) to elucidate relations among the social communication signs and symptoms and underlying cognitive impairments. What this paper adds What are the potential or actual clinical implications of this work? More awareness and understanding of how social cognition may look in everyday conversations, may help SLPs who treat patients with such difficulties as a result of TBI.