Longitudinal assessment of awareness in early-stage Alzheimer's disease using comparable questionnaire-based and performance-based measures: a prospective one-year follow-up study.

Few studies of awareness in dementia have taken a longitudinal perspective, yet exploring the ways in which awareness changes over time may offer important information about the processes involved and the relationship between awareness and other variables. The present study explored in detail the patterns of change in awareness scores over time for a group of 12 participants with early-stage Alzheimer's disease using a multi-dimensional measure giving comparable participant-carer and post diction-performance discrepancy scores. There were small, non-significant increases in mean discrepancy scores for each of these components of the assessment, with similar patterns for questionnaire-based and performance-based ratings. The small changes that were observed reflected both participant and informant factors. The majority of participants showed only very minor changes; others showed changes in the direction of either reduced or increased awareness. There was no significant association between change in mean discrepancy score and change in MMSE score over time, although there was a significant decline in MMSE scores at follow-up. The observation of different longitudinal trajectories for awareness scores, reflecting increased or decreased awareness or no change, may indicate the operation of different processes affecting the expression of explicit awareness that can be understood within a biopsychosocial formulation of this complex construct.