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.

Temporal lobe epilepsy alters neural responses to human and avatar facial expressions in the face perception network.

BACKGROUND AND OBJECTIVE: Although avatars are now widely used in advertisement, entertainment, and business today, no study has investigated whether brain lesions in neurological patients interfere with brain activation in response to dynamic avatar facial expressions. The aim of our event-related fMRI study was to compare brain activation differences in people with epilepsy and controls during the processing of fearful and neutral dynamic expressions displayed by human or avatar faces. METHODS: Using functional magnetic resonance imaging (fMRI), we examined brain responses to dynamic facial expressions of trained actors and their avatar look-alikes in 16 people with temporal lobe epilepsy (TLE) and 26 controls. The actors' fearful and neutral expressions were recorded on video and conveyed onto their avatar look-alikes by face tracking. RESULTS: Our fMRI results show that people with TLE exhibited reduced response differences between fearful and neutral expressions displayed by humans in the right amygdala and the left superior temporal sulcus (STS). Further, TLE was associated with reduced response differences between human and avatar fearful expressions in the dorsal pathway of the face perception network (STS and inferior frontal gyrus) as well as in the medial prefrontal cortex. CONCLUSIONS: Taken together, these findings suggest that brain responses to dynamic facial expressions are altered in people with TLE compared to neurologically healthy individuals-regardless of whether the face is human or computer-generated. In TLE, areas sensitive to dynamic facial features and associated with processes relating to the self and others are particularly affected when processing dynamic human and avatar expressions. Our findings highlight that the impact of TLE on facial emotion processing must be extended to artificial faces and should be considered when applying dynamic avatars in the context of neurological conditions.