Differentiation of dementia of the Alzheimer's type from depression with cognitive impairment on the basis of a cortical versus subcortical pattern of cognitive deficit

This study compared 15 "mildly" cognitively impaired participants with Deme ntia of the Alzheimer Type (DAT), 15 depressed cognitively impaired partici pants (DCI), and 15 normal participants. The participants were matched for age, and reading ability, and were rested on a series of cognitive instrume nts selected on the basis of their ability to distinguish a cortical versus subcortical pattern of deficit. The DAT group demonstrated impaired perfor mances on tests of language, praxis and gnosis. Deficits in these areas wer e absent from DCI group. There were differences between all of the groups o n the California Verbal Learning Test, but after this effect was controlled using an analysis of covariance procedure, the differences in tests of gno sis, praxis and language function between the DCI and the DAT participants still remained. These findings support the clinical usefulness of the corti cal-subcortical distinction in differentiating DCI from DAT. (C) 1999 Natio nal Academy of Neuropsychology. Published by Elsevier Science Ltd.