Diagnostic Performance of Socio-Emotional Informant-Based Questionnaires for the Clinical Detection of the Behavioral Variant of Frontotemporal Dementia

Background: Although social cognitive dysfunction is a major feature of the behavioral variant of frontotemporal dementia (bvFTD), quantitative measurement of social behavior changes is poorly available in clinical settings. Objective: The aim of the study is to evaluate diagnostic accuracy of social-emotional questionnaires in distinguishing bvFTD from healthy control (HC) subjects and Alzheimer's disease (AD) patients. Methods: We enrolled 29 bvFTD, 24 AD, and 18 HC subjects matched for age, sex, and education. Two informant-based measures of socio-emotional sensitivity and empathy (i.e., revised Self-Monitoring Scale (rSMS) and Interpersonal Reactivity Index (IRI)) were administered. One-way ANOVA was performed to compare groups, whereas Receiver Operating Characteristics (ROC) curve analysis tested questionnaire ability in distinguishing groups. A short version of IRI (sIRI) was obtained by excluding the non-contributing subscale (i.e., personal distress). Results: Compared to HC and AD, bvFTD showed significantly lower scores in rSMS and IRI scores, except for IRI personal distress subscale. The sIRI showed an excellent performance in early diagnosis (bvFTD versus HC = AUC 0.95). Both sIRI and rSMS showed good performance in distinguishing bvFTD from AD (AUC 0.83). Conclusions: ROC analyses support the usefulness of informant social questionnaires in memory clinics and their potential value in screening procedures for research eligibility in forthcoming trials. In the timely diagnosis of bvFTD patients, IRI and rSMS may supply crucial information for the early detection of signs and symptoms affecting social-emotional skills, which might otherwise be underrecognized.