Awareness, apathy, and depression in Alzheimer's disease and mild cognitive impairment

Results from studies on awareness disorders in Alzheimer's disease (AD) are controversial because the methodologies, the "objects" of awareness, and the patients' pathologic stage all vary. Our study aimed to compare scores and correlates of awareness according to the stage of the disease and the assessment method.

We compared 20 mild AD patients to 20 mild cognitive impairment (MCI) patients, using the Patient Competency Rating Scale (PCRS; patient vs. caregiver report) and the Self-Consciousness Scale (rating scale). All patients underwent cognitive, psycho-affective and behavioral assessments (global cognition, executive functions, episodic memory, anxiety-depression, and apathy measures).

Groups were matched for age, education, and gender. They were comparable on the depression, anxiety, apathy and awareness scales (ps > .05), and differed for all cognitive variables (p < .05). Using the median split approach, greater apathy and lower depression were associated with poorer awareness on the Self-Consciousness Scale (respectively: odds ratio [OR] = 4.8, p = .03; OR = 4.84, p = .04), and the PCRS (only apathy: OR = 9.3, p = .003). Greater apathy plus lower depression were associated with poorer awareness in both scales (PCRS: OR = 40.5, p = .005; Self-consciousness scale: OR = 28, p = .012).

These results evidence comparable awareness between AD and MCI patients. The correlates were more affective and behavioral than cognitive, independently from assessment method.