Awareness dimensions and associated factors in Alzheimer's disease

We recently reported the major role depression and apathy in awareness among Alzheimer patients, using the stage of the disease as an exposure factor and exploring different assessment methods. Using the same patient data, we aimed here to explore the different dimensions of awareness assessed by different sub-scales in awareness scales.

Sixty-one Alzheimer patients were examined using four awareness scales relating to three assessment methods: (a) patient-caregiver discrepancy; (b) clinical rating; and (c) prediction of performance discrepancy. Global cognition, executive functioning, autonomy, depression and apathy were also assessed. Multivariate logistic models were performed using disease stage as an exposure factor for awareness scales and sub-scales. Correlations across the different factors and patient and caregiver awareness ratings were computed.

The patient-caregiver discrepancy and clinical rating methods (a, b) both identified the factors associated with awareness in the overall scales and the sub-scales as being depression and/or apathy. Depression correlated with patient self-ratings while apathy correlated with caregiver ratings. The prediction of performance discrepancy method (c) identified different factors in the overall scale, executive factors in three sub-scales involving executive domains and the memory factor in a sub-scale involving the mnesic domain.

The awareness scales using a referential based on a human rating (a, b) suggest that awareness is unidimensional, with depression impacting self-reports and apathy influencing caregiver/clinical reports. Scales based on a test rating (c) appear to be more closely associated with the dimensions assessed. This highlights the role of the reference system for awareness assessment in Alzheimer's disease.