The heterogeneity of anosognosia for memory impairment in Alzheimer's disease: a review of the literature and a proposed model

Anosognosia for memory impairment is a phenomenon in Alzheimer's disease that has historically only been noted anecdotally. It is only recently that it has been investigated independently. Varying methodologies have been employed to examine the neuropsychological correlates of anosognosia in AD. There have been markedly discrepant results with severity of disease, extent of memory deficit and dysexecutive syndrome being those correlates most widely reported. A review of this literature is given and previously proposed models discussed critically in terms of three widely accepted phenomena: the variability in degree of anosognosia and the specificity with regard to cognitive domain and personal deficit as opposed to a generalized deficit in judgement. The case for heterogeneity of anosognosia for memory impairment is made and a comprehensive cognitive model is presented.