The rationale of the published paper in Brain is clear. bvFTD is a frequent cause of early-onset dementia. The diagnosis remains challenging because of the limited accuracy of neuroimaging in the early disease stages and the absence of molecular biomarkers, and therefore relies predominantly on clinical assessment. Moreover, bvFTD shows significant symptomatic overlap with non-degenerative primary psychiatric disorders including major depressive disorder, bipolar disorder, schizophrenia, obsessive-compulsive disorder, autism spectrum disorders and even personality disorders.

With the international NIC-FTD consortium the researchers wanted to review the existing literature on the diagnosis of bvFTD and its differential diagnosis with PPD. They came up with new recommendations for the assessment of bvFTD in patients with late-onset behavioral changes.These recommendations include performing at least one formal social cognition test in the standard neuropsychological battery for bvFTD. The authors emphasize the importance of 3D-T1 brain MRI with a standardized review protocol including validated visual atrophy rating scales, and to consider volumetric analyses if available. The role of 18F-fluorodeoxyglucose PET for the exclusion of bvFTD when normal, whereas non-specific regional metabolism abnormalities should not be over-interpreted in the case of a psychiatric differential diagnosis. They highlight the potential role of serum or CSF neurofilament light chain to differentiate bvFTD from primary psychiatric disorders. Finally, based on the increasing literature and clinical experience, the consortium determined that screening for C9orf72 mutation should be performed in all possible/probable bvFTD cases or suspected cases with strong psychiatric features.

Read the publication in Brain Recommendations to distinguish behavioural variant frontotemporal dementia from psychiatric disorders.