Language and dementia: a review.

In the literature on dementia the presence or absence of language deficits has come to occupy a pivotal position with respect to certain nosological and nosographical issues. These are reviewed critically, together with the results of experimental investigations which have sought to elucidate the nature of the language deficit(s) in patients with dementia, especially that of the Alzheimer type. Attention is drawn to important gaps in current knowledge and suggestions are made regarding the direction of future research.