Social reasoning, emotion and empathy in frontotemporal dementia

Introduction: Social cognition is crucial for human interaction, and is markedly impaired in the frontal variant of frontotemporal dementia (fvFTD). The relationship of various aspects of social functioning, however, remains controversial in this group. Methods: Patients with fvFTD (n = 18), and matched controls (n = 13), were tested using tasks designed to assess their Theory of Mind (ToM), moral reasoning, emotion recognition and executive function. Caregivers documented changes in empathy compared to premorbid functioning. Results: We found marked impairments in the abilities of fvFTD patients, relative to controls, in ability to mentalise (ToM), which was evident on a cartoon test, but not on a story-based ToM task. Knowledge of social rules was intact, but moral reasoning was defective, and was due, in part, to an inability to rate the seriousness of moral and conventional transgressions appropriately. Executive function was impaired in this group, and compromised aspects of moral reasoning, but ToM performance was independent of this. Emotion recognition was globally impaired in fvFTD, but was particularly so for anger and disgust which may partly explain the difficulty these patients have with identifying social violations. Empathy, as rated by carers, was also shown to be abnormal. Conclusion: It appears that social reasoning is disrupted in a number of ways in fvFTD, and the findings provide a basis for the understanding and further study of abnormal behaviour in this disease. The results are discussed in light of neuroimaging findings in studies of social cognition and the locus of pathology in fvFTD.