Evaluation of Emotional Blunting in Behavioral Variant Frontotemporal Dementia Compared to Alzheimer's Disease

Background: Emotional blunting is a major clinical feature of behavioral variant frontotemporal dementia (bvFTD). Assessing the change in emotional blunting may facilitate the differential diagnosis of this disorder and can quantify a major source of distress for the patients' caregivers and families. Methods: We evaluated investigator ratings on the Scale for Emotional Blunting (SEB) for 13 patients with bvFTD versus 18 patients with early-onset Alzheimer's disease (AD). The caregivers also performed SEB ratings for both the patients' premorbid behavior (before dementia onset) and the patients' behavior on clinical presentation (after dementia onset). Results: Before the onset of dementia, the caregivers reported normal SEB scores for both dementia groups. After the onset of dementia, both caregivers and investigators reported greater SEB scores for the bvFTD patients compared to the AD patients. The patients were rated to be much more emotionally blunted by the bvFTD caregivers than by the investigators. A change of >= 15 in the caregiver SEB ratings suggests bvFTD. The change in caregiver SEB ratings was positively correlated with bifrontal hypometabolism on FDG-PET scans. Conclusions: Changes in the caregiver assessment of emotional blunting with dementia onset can distinguish patients with bvFTD from those with AD, and they may better reflect the impact of emotional blunting than similar assessments made by clinicians/investigators. (C) 2014 S. Karger AG, Basel