A comparative study of social cognition in epilepsy, brain injury, and Parkinson's disease

The brain regions involved in social cognition and the regulation of social behavior form a widely distributed cortico-subcortical network. Therefore, many neurological disorders could affect social cognition and behavior. A persistent lack of valid tests and a rigid neuropsychological focus on language, attention, executive function, and memory have contributed to a long-standing neglect of social cognition in clinical diagnostics, although the DSM-5 recognizes it as one of the six core dimensions in neurocognitive disorders. To assess for the first time the diagnostic yield of a comprehensive social cognition battery (Networks of Emotion Processing [NEmo]), we administered several emotion recognition and theory of mind tests to three incidental clinical samples with different neurological conditions: temporal lobe epilepsy (n = 30), acquired brain injury (n = 24), Parkinson's disease (n = 19), and a healthy control group (n = 67). A multivariate analysis of covariance was performed to test the effect of group on subscales of the NEmo test battery, controlling for age and performance IQ. The results showed statistically significant differences between clinical groups and healthy controls. No differences were found for gender and lateralization of the predominant lesion side. In our incidental samples, 86% of individuals with temporal lobe epilepsy, 57% of individuals with acquired brain lesion, and 14% of individuals with Parkinson's disease underperformed on tests of social cognition compared with controls. These findings suggest a differential impact of neurological disorders on the risk of impaired social cognition and highlight the need to consider social cognition in diagnostics, counselling, therapy, and rehabilitation.