Visual rating scales of atrophy differentiate sporadic behavioral variant frontotemporal dementia from primary psychiatric disorder: DIPPA study

: Sporadic behavioral variant frontotemporal dementia (bvFTD) is often misdiagnosed as late-onset primary psychiatric disorder (PPD) due to overlapping symptoms and lack of disease-specific biomarkers. This multicenter pilot study aimed to identify brain atrophy patterns using visual rating scales (VRS) that distinguish between groups, and to compare VRS performance with standard clinical assessment. Magnetic resonance images from bvFTD and PPD patients across five centers were retrospectively reviewed. One rater, blinded for the clinical diagnosis, applied eight VRS. Group differences were assessed, the most predictive scales were identified and combined into a composite score, and the predictivity compared. 297 bvFTD and 92 PPD patients were analysed. All VRS yielded higher atrophy in bvFTD than in PPD patients. The Orbitofrontal, the Anterior-Temporal, and the Fronto-Insula scales were the strongest discriminators, and their composite score outperformed any individual scale. VRS may provide useful diagnostic support for distinguishing bvFTD from PPD.