[Pick and focal brain atrophy].

In 1892 Arnold Pick presented the case of an elderly demented patient with severe aphasia and global brain atrophy most accentuated at the left temporal lobe. Picks main interest was the relationship between focally accentuated brain degeneration and focally accentuated neuropsychological deficits, and this was what he wanted to demonstrate. He made no effort to describe a new form of dementia. The term "Pick's disease" which was introduced 30 years later implies the existence of a nosological entity with characteristic clinical features, localisation and histology. The neuropathological causes of focally accentuated brain atrophies are varied. Neocortical pyramidal cell loss with or without spongiform changes, cortical and subcortical gliosis have commonly been described. Achromatic neuronal ballooning ("Pick's cells") and intraneuronal argentophilic inclusion bodies ("Pick's bodies"), Alzheimer type plaques and tangles and other features were found in a smaller number of cases. Several authors confirmed an association between the localisation of brain atrophy and its clinical manifestations, but no convincing relationship has been demonstrated between the clinical symptoms and the underlying histology. In several studies frontal lobe degeneration was found in 10% to 20% of the demented patients, whereas aphasia, apraxia and other pronounced deficits in the context of focally accentuated brain atrophy were described less frequently. An early clinical distinction between atypical early stages of Alzheimer's disease and other forms of slowly progressive dementing disorders is virtually impossible in these cases. Prospective studies documenting the clinical and anatomical findings are needed to examine the reliability of these surmised brain-behaviour relationships in degenerative brain diseases more reliably. A descriptive approach offers a better basis for data collection than the premature diagnosis of a poorly defined disease like "Pick's".