Patterns of impairment in decision-making capacity in Alzheimer's disease and its relationship with cognitive and clinical variables

Objectives: To investigate the patterns of impairment in decision-making abilities and their relationship with cognitive and clinical symptoms in people with Alzheimer's disease. We hypothesized that decision-making abilities would not be impaired at the same level and would be related to impairment of global cognition and other clinical symptoms of the disease. Methods: Using a cross-sectional design, we included a consecutive sample of 102 people with Alzheimer's disease and their respective caregivers. We investigated the relationship between decision-making capacity and quality of life (QoL), disease awareness, mood, functionality, neuropsychiatric symptoms, and cognition. Results: Different levels of impairment were observed in the participants' decision-making abilities. Understanding, appreciation, and reasoning were correlated, but expressing a choice was only correlated with appreciation. Deficits in understanding were related to impaired disease awareness, lower self-reported QoL, and lower comprehension of spoken language. Better appreciation was related to better orientation and lower age. Better reasoning was related to better orientation and better self-reported QoL. Deficits in expressing a choice were related to lower self-reported QoL. Conclusion: The pattern of impairment in decision-making abilities was not linear. Each decision-making ability was related to different cognitive and clinical deficits. Therefore, cognitive functioning is an insufficient criterion for judging an individual's decision-making ability.