Concordance between observers in descriptions of personality change in Alzheimer's disease.

To evaluate observer bias and to estimate observer concordance for descriptions of personality changes in dementia, the authors examined the personality descriptions of dementia patients provided by 2 informants. Twenty-two patients with Alzheimer's disease were rated on the NEO-PI by each of 2 informants, the primary caregiver and another relative or friend. Each informant completed the NEO-PI to describe current behavior and premorbid behavior. Significant differences between premorbid and current descriptions were found for 4 of the 5 personality dimensions measured. There was substantial agreement between independent raters, as indicated by significant correlations between raters for 4 dimensions and the absence of significant differences between rater averages. These results suggest that both primary caregivers and others who know a patient well may serve as informants for studies of personality in dementia.