Neural correlates of empathic impairment in the behavioral variant of frontotemporal dementia

Objective: Loss of empathy is a symptom of the behavioral variant of frontotemporal dementia (bvFTD), constituting a clue for early diagnosis. In this study, we directly compared two empathy components (intention attribution [IA] and emotion attribution [EA]), correlating them with possible specific patterns of gray-matter density reduction within the mentalizing network. Methods: We evaluated IA and EA in 18 mild bvFTD patients compared with 36 healthy controls (HCs) using a single nonverbal test. A subgroup entered a voxel-based morphometry study. Results: Compared with HC, bvFTD patients showed IA and EA impairments. EA performance correlated with gray-matter reduction in the right amygdala, left insula, and posterior-superior temporal sulcus extending into the temporoparietal junction. Conclusion: We proved an empathic impairment, with the ability to infer emotional states showing the most severe deficit. These results provide further evidence of selective disease-specific vulnerability of the limbic and frontoinsular network in bvFTD and highlight the usefulness of empathy assessment in early patients. (C) 2014 The Alzheimer's Association. All rights reserved.