Unawareness of cognitive deficit in Alzheimer disease and related dementias.

The objective of this study was to determine whether unawareness of cognitive deficit is disease-specific. One hundred thirty-two patients were studied, grouped according to diagnosis of definite or probable Alzheimer disease, vascular dementia, geropsychiatric control, or geriatric control. Diagnosis was the independent variable, and unawareness of cognitive deficit was the dependent variable. The Mini-Mental State Examination score was used as a dementia severity covariate. Analysis of covariance was significant (F = 8.0, p < 0.0001). Follow-up mean comparisons showed the Alzheimer disease group to have significantly greater unawareness of cognitive deficit than all other groups. The vascular dementia group had significantly greater unawareness of cognitive deficit than the two control groups. These results support the premise that, independent of dementia severity, unawareness of cognitive deficit is disease specific.