Unawareness of deficits in Alzheimer's disease and other dementias: operational definitions and empirical findings.

Individuals with dementia frequently demonstrate decreased awareness of their cognitive difficulties. Empirical research examining this phenomenon has addressed a number of aspects of unawareness in Alzheimer's disease and other dementias, including occurrence in various disorders; possible neuroanatomical substrates; relationship to general cognitive functioning, executive functioning, and psychiatric symptomatology; and progression over time and across cognitive domains. Limitations of the current research literature are discussed, particularly issues surrounding operational definitions of unawareness and the current limited understanding of the role of the frontal lobes. A number of conclusions regarding unawareness that appear to be supported by the current body of empirical research and possible future directions are discussed.