Frontotemporal Lobar Degeneration from the Perspective of the New Clinical-Pathological Correlations

The disease currently known as Frontotemporal Lobar Degeneration (FTLD) underwent a complicated development. From its first description by Arnold Pick and Alois Alzheimer, through the first clinical and pathological criteria introduced by David Neary and David Mann to the current perception of the disease as a complex clinical and pathological entity. At present, the Frontotemporal Lobar Degeneration is understood to be a heterogeneous clinical syndrome caused by degeneration of the frontal and temporal lobes. FTLD can manifest as any of the three clinical syndromes of frontotemporal dementia (behavioural variant of frontotemporal dementia, progressive non-fluent aphasia and semantic dementia) as well as so called overlap syndromes encompassing corticobasal dementia and progressive supranuclear palsy. FTLD represents approximately 10% of all cases of dementia but 40% of cases of early onset dementia (between the age of 45 and 65 years). Although FTLD subtypes differ in their clinical manifestation, common denominators include behavioural disturbances and impairment of fatic, gnostic and executive functions. Mnestic and visual-spatial functions are preserved until advanced stages of the disease. Compared to Alzheimer's disease, the FTLD usually onsets at an earlier age and causes more devastating impairment of cognitive domains. Persons affected by FTLD become more quickly dependent on the help of other person or an institution. In our paper, we provide an overview of this complex entity, focusing mainly on frontotemporal dementia syndromes.