Aphasia in dementia of the Alzheimer type.

Speech and language assessment in 30 patients with dementia of the Alzheimer type and in 70 normal controls revealed that all Alzheimer patients were aphasic. Throughout most of the course, the language disorder resembled transcortical sensory aphasia, and increasing language impairment correlated with increasing severity of dementia. Aphasia was present regardless of age of onset or family history of dementia. Aphasia is an important diagnostic criterion of dementia of the Alzheimer type.