Awareness dimensions and associated factors in Alzheimer's disease

An Update on Apathy in Alzheimer's Disease

Apathy is a complex multi-dimensional syndrome that affects up to 70% of individuals with Alzheimer's disease (AD). Whilst many frameworks to define apathy in AD exist, most include loss of motivation or goal-directed behaviour as the central feature. Apathy is associated with significant impact on persons living with AD and their caregivers and is also associated with accelerated cognitive decline across the AD spectrum. Neuroimaging studies have highlighted a key role of fronto-striatial circuitry including the anterior cingulate cortex (ACC), orbito-frontal cortex (OFC) and associated subcortical structures. Importantly, the presence and severity of apathy strongly correlates with AD stage and neuropathological biomarkers of amyloid and tau pathology. Following from neurochemistry studies demonstrating a central role of biogenic amine neurotransmission in apathy syndrome in AD, recent clinical trial data suggest that apathy symptoms may improve following treatment with agents such as methylphenidate-which may have an important role alongside emerging non-pharmacological treatment strategies. Here, we review the diagnostic criteria, rating scales, prevalence, and risk factors for apathy in AD. The underlying neurobiology, neuropsychology and associated neuroimaging findings are reviewed in detail. Finally, we discuss current treatment approaches and strategies aimed at targeting apathy syndrome in AD, highlighting areas for future research and clinical trials in patient cohorts.

Apathy Is the Best Dimension to Consider for Awareness Assessment in Alzheimer’s Disease

Previous studies have reported the major role of apathy in awareness assessment among Alzheimer’s patients using the patient-caregiver discrepancy method, whatever the awareness dimension assessed. Using the Apathy Evaluation Scales among other awareness scales, we report that apathy is the sole awareness dimension distinguishing healthy controls (25), mild (57) and moderate-to-moderately-severe (11) Alzheimer’s patients. A linear regression showed that the Mini-Mental State Examination score used as a risk factor for non-awareness was the only factor associated with awareness of apathy and was the best predictor. This suggests that apathy is the most discriminant dimension for awareness assessment in Alzheimer’s disease.