Progressive focal cortical atrophies.

Progressive focal cortical atrophies are degenerative conditions characteri sed by the insidious onset and gradual exacerbation of an impairment in a s ingle cognitive domain related to circumscribed cerebral atrophy Several fo cal cortical syndromes with deficits in the realm of cognition are reviewed : progressive impairment of language (primary progressive aphasia), speech (progressive anarthria), semantic memory (semantic dementia), episodic memo ry (pure progressive amnesia), vision (progressive perceptual or visuo-spat ial deficits) and gesture (progressive apraxia). These conditions are histologically heterogeneous and can be associated wit h focal non-specific neuronal loss and gliosis with some spongiform changes (non-specific lesions), pathological features of Pick's disease (inclusion bodies and swollen neurones) or Alzheimer's disease (AD) (senile plaques a nd neurofibrillary tangles). A relationship between neuropsychological profiles and lesional types emerg es from this review of the literature. Non-fluent primary progressive aphas ia, semantic dementia and progressive anarthria are usually associated with non-specific lesions and Pick-type pathology. Progressive disorders of epi sodic memory and progressive visuo-spatial deficits are more often related to AD. If adequate clinical characterisation can determine the underlying d isorder, it appears even more important to establish the neuropsychological profile in patients with cortical degenerative disease. Progressive deficits of only one domain of cognition may well be due to pre ferential involvement of anatomically and functionally defined neural syste ms and could therefore be considered as "system atrophies". There remains n o doubt that these syndromes are particularly well suited models for studie s on the relationship between cerebral functions and their neural substrate .