Validation of the Cognitive-Emotional Perspective Taking test in patients with neurodegeneration

Background: Theory of mind (ToM) is crucial for socioemotional interaction. ToM deficits may explain behavioral changes in dementia, especially Alzheimer's disease (AD) and frontotemporal dementia (FTD). Objective: This study examined the psychometrics of a new ToM test in healthy adults, identified ToM differences in dementia syndromes, and assessed if ToM scores predict neuropsychiatric function and real-life behavior. Methods: The UCSF Cognitive and Emotional Perspective Taking Test (CEPT) was evaluated in 195 healthy adults (age: 42.69 ± 16.20) and in a clinic cohort of 304 participants (age: 64.07 ± 9.2). Participants included healthy controls, AD, behavioral-variant frontotemporal dementia (bvFTD), semantic variant primary progressive aphasia (svPPA), non-fluent PPA (nfvPPA), and progressive supranuclear palsy (PSP) patients. CEPT's psychometrics were assessed, and ToM differences and predictions of neuropsychiatric symptoms were analyzed using regression models. Results: In controls, CEPT showed good validity and reliability. In patients, CEPT scores correlated with executive and emotional measures, but not language measures, showing good construct validity. Cognitive ToM was most impaired in AD and bvFTD, with less impairment in svPPA and PSP, and all patient groups showed impaired emotional ToM. ToM performance predicted real-life neuropsychiatric behavior, including anxiety, apathy, disinhibition, and aberrant motor behaviors. Conclusions: ToM deficits appear early in dementia syndromes and predict neuropsychiatric behavior. Assessing ToM and social cognition with ecologically valid tasks may help identify altered social cognition in early neurodegeneration.