Longitudinal changes in awareness over 36 months in patients with mild Alzheimer's disease

Longitudinal changes in awareness in dementia have been studied with short follow-up time and mostly in small patient groups (including patients with moderate dementia). We investigated awareness in patients with mild Alzheimer's disease (AD) over 36 months and studied if a decline in awareness was associated with decline in cognition and increase in neuropsychiatric symptoms.

Awareness was measured on a categorical scale in 95 AD patients (age ≥50 years, Mini-Mental State Examination (MMSE) score ≥20). Awareness was rated at three time points (follow-up at 12 and 36 months) where MMSE, Neuropsychiatric Inventory (NPI-Q), and Cornell scale for Depression in Dementia also were applied.

At 12 months, 26% had lower awareness rating as compared to baseline and at 36 months lower awareness ratings were found in 39%. At both visits, 16% had higher awareness rating as compared to baseline. Patients with lower awareness at 36 months as compared to baseline had a more rapid increase in NPI-Q score (p = 0.002) over 36 months as compared to patients with stable or improved awareness over 36 months. A more rapid decline in MMSE score was observed for patients with lower awareness at 36 months (as compared to baseline) but only when compared to patients in whom awareness improved over time.

The results show essentially no clear relationship between cognitive decline over three years and awareness. In some cases, awareness remained stable or even improved despite significant cognitive decline. In the subgroup where awareness declined over time, overall ratings of neuropsychiatric symptoms declined more rapidly than in the remaining patients.