Aims: The aims of this study were to assess the sensitivity of the International Behavioural Variant FTD Criteria Consortium (FTDC) revised criteria of behavioural variant frontotemporal dementia (bvFTD) in a pathological cohort and to determine their predictive values in a clinical context suggestive of bvFTD. In addition, the study aimed to assess the influence of the age at onset and underlying pathology in the clinicopathological correlations.
Methods: Retrospective, blinded review of the clinical and neuropathological data from the Neurological Tissue Bank of the Biobank Hospital Clinic-IDIBAPS, Barcelona (Spain) was conducted, assessing the fulfilment of the diagnostic criteria on a case-by-case basis. Two separate nonexclusive cohorts were selected: Cohort 1 (n = 58) subjects with pathological diagnosis of frontotemporal lobar degeneration (FTLD) and Cohort 2 (n = 66) subjects with the premortem diagnosis of bvFTD.
Results: The FTDC criteria reached a sensitivity of 93% for possible and 80% for probable bvFTD. Early-onset cases displayed significantly more disinhibition, loss of empathy and compulsive behaviour with respect to late-onset bvFTD, leading to a slightly higher sensitivity of the diagnostic criteria (97% vs. 91%). There were no differences in the diagnostic performance between tau-positive and tau-negative cases. In subjects clinically diagnosed as bvFTD, a 'possible bvFTD' diagnosis reached a positive predictive value for FTLD pathology of 90%, irrespective of underlying proteinopathy. False-positive clinical diagnoses were mainly Alzheimer's disease. These cases were significantly older, had less family history of dementia and had a predominantly apathetic clinical picture.
Conclusions: The revised bvFTD criteria present good sensitivity and positive predictive value in both early- and late-onset cases and regardless of the underlying FTLD pathology.
Keywords: behavioural variant; diagnostic criteria; frontotemporal dementia.
© 2014 British Neuropathological Society.