Exploring fixation patterns and social cognition after traumatic brain injury

Objectives: Social cognition (SC) impairments after traumatic brain injury (TBI) are pervasive. The movie for the assessment of social cognition (MASC) measures different facets of social interactions over the three stages of SC; social perception, social knowledge retrieval and response selection. The mechanisms underpinning SC deficits after TBI are poorly understood but aberrant eye fixation patterns could play a role. The present research explored fixations across social interactions to determine group differences and correlations between eye tracking and behavioural data. Design: Group differences in response selection during the MASC and fixation duration/count to areas of interest (eyes, nose and mouth) were examined. Methods: 18 TBI participants were recruited from the NHS and age/gender matched controls were recruited using stratified opportunity sampling. The MASC allows for quantification of incorrect answers; excessive theory of mind (ToM), reduced ToM and absence of ToM errors. The MASC was presented on a Tobii T120 eye tracker monitor. Results: TBI participants had significantly lower correct scores on the MASC and higher excessive/reduced errors compared to controls. There was no significant interaction between automated optical inspection (AOI) and group. However, significant main effects of group for fixation duration/count indicated that if AOI was ignored, controls displayed longer/more fixations overall suggesting a difference in visual scanning patterns between TBI and control groups. No significant correlations were established. Conclusions: TBI and controls exhibited disparate visual strategies during the MASC and this effect could underpin some SC impairments displayed by TBI participants. TBI participants also displayed insufficient and over-interpretative mental state reasoning compared to controls but it is unclear why. The present research outlines the multifaceted nature of SC impairments after TBI and highlights potential areas for SC intervention post-TBI