The behavioral variant of frontotemporal dementia: linking neuropathology to social cognition.

The behavioral variant of frontotemporal dementia (bvFTD) is one of the most frequent neurodegenerative disorders with a presenile onset. It is characterized by a long phase of subclinical behavioral changes and social conduct disorders, associated with a progressive modification of personality. Recently, an international consortium of experts developed revised guidelines for its clinical diagnosis, which highlight the supportive role of biomarkers in the diagnostic process. According to new criteria, bvFTD can be classified in "possible" (requiring three of six specific clinical features), "probable" (in the presence of functional disability and typical neuroimaging features), and "with definite frontotemporal lobar degeneration" (requiring the presence of a known causal mutation or a histopathological confirmation). Familial aggregation is frequently reported in bvFTD and frontotemporal lobar degeneration in general, with an autosomal dominant transmission in about 10 % cases. The aim of this paper is to review and discuss recent advances in the knowledge of clinical, neuropsychological, and imaging features of bvFTD. We also briefly summarize the available genetic information about the frontotemporal lobar degeneration spectrum.