Measures of Awareness in Alzheimer's Disease and Clinical Differences Between Groups with Preserved, Impaired, and Absent Awareness.

Background: Awareness is a heterogeneous construct that requires accurate assessment. There is no consensus on the best methodology for capturing the phenomenon, thus leading to inconsistent results in this area. Objective: We aim to evaluate the reliability of clinicians' ratings and a discrepancy assessment method, examining groups of people with Alzheimer's disease (PwAD) according to their degree of awareness and demographic and clinical aspects. Methods: We cross-sectionally assessed 134 PwAD and their caregivers. Individuals' level of awareness was assessed with two methods: clinicians' ratings identified three groups (preserved awareness, impaired awareness, and absent awareness), while discrepancy assessment identified four groups (preserved awareness, mildly impaired awareness, moderately impaired awareness, and absent awareness). Results: Clinicians' ratings showed significant differences between PwAD with preserved, impaired, and absent awareness groups in cognition, functionality, and neuropsychiatric symptoms. There was a significant difference in caregivers' anxiety between the impaired and absent awareness groups. Discrepancy assessment showed no clinical differences between the preserved and mildly impaired awareness groups or between the absent and moderately impaired awareness groups. A significant difference in functionality was observed between the other groups. Conclusions: Clinical aspects of each measure tended to differ between the chosen methods. Impairments in awareness fluctuate despite disease progression. Cognition and severity of disease cannot explain deficits in awareness.