[Progressive focal cortical atrophies].

Progressive focal cortical atrophies are degenerative conditions characterised by the insidious onset and gradual exacerbation of an impairment in a single cognitive domain related to circumscribed cerebral atrophy. Several focal 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 memory (pure progressive amnesia), vision (progressive perceptual or visuo-spatial deficits) and gesture (progressive apraxia). These conditions are histologically heterogeneous and can be associated with 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 and neurofibrillary tangles). A relationship between neuropsychological profiles and lesional types emerges from this review of the literature. Non-fluent primary progressive aphasia, semantic dementia and progressive anarthria are usually associated with non-specific lesions and Pick-type pathology. Progressive disorders of episodic memory and progressive visuo-spatial deficits are more often related to AD. If adequate clinical characterisation can determine the underlying disorder, 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 preferential involvement of anatomically and functionally defined neural systems and could therefore be considered as "system atrophies". There remains no doubt that these syndromes are particularly well suited models for studies on the relationship between cerebral functions and their neural substrate.