Background: Emotions, with or without moral valence, appear to be altered in the behavioral variant of frontotemporal dementia (bvFTD) but the relative degree of moral emotion breakdown, which could be a marker of bvFTD diagnosis, remains unexplored.
Objective: To assess moral emotions in bvFTD, to differentiate bvFTD from typical Alzheimer's disease (AD) based on moral emotion processing, and to provide a sensitive and specific assessment tool contributing to bvFTD diagnosis.
Methods: We investigated moral emotions in 22 bvFTD patients, 15 patients with typical AD having positive CSF AD biomarkers, and 45 healthy controls. The 'Moral Emotions Assessment' task consisted in 42 scenarios exploring positive and negative moral emotions. To control for moral-specificity, we contrasted the 42 moral scenarios with 18 extra-moral scenarios eliciting the emotions without involving any inter-human moral context.
Results: bvFTD patients were more impaired in emotion processing than AD patients and healthy controls and had significantly poorer performance in the processing of moral emotions than of emotions without moral valence. ROC analyses of data on moral scenarios showed a high area under the curve (83%), and indicated a cut-off score (< 37/42) for differentiating bvFTD from AD with a sensitivity of 82% and specificity of 73%.
Conclusion: Our findings demonstrate that bvFTD patients have disorders in emotion processing which is mainly related to failure regarding moral emotions. They also show that this deficit is reliably detected by the 'Moral Emotions Assessment' which represents a sensitive and specific diagnostic tool detecting bvFTD and differentiating it from AD.
Keywords: Alzheimer’s disease; frontotemporal dementia; moral emotions.