Determining best-in-practice dyadic discrete choice experiments to enable persons with dementia and informal caregivers to participate in health care decision-making: a feasibility study

Background: Discrete choice experiments (DCEs) are a powerful tool that potentially offer a method to quantify individual and joint care preferences of persons with dementia and their informal caregivers. DCE studies that have included persons with dementia revealed that choice task complexity is a serious challenge to this population, which can lead to heuristic decision making. This feasibility study aims to determine best-in-practice dyadic DCE design to enable both persons with dementia and informal caregivers to participate in health care decision-making. Method: This study included three DCE rounds: (1) persons with dementia alone, (2) informal caregiver only, and (3) persons with dementia and their informal caregivers in dyads. A flexible DCE design was employed, in which choice task complexity was increased systematically to explore individual cognitive limitations in DCE decision making. Choice tasks were presented by illustrations and simplified language to decrease cognitive burden on persons with dementia. A think aloud approach of survey administration was used to provide insights into individual and joint decision-making processes. The Telephone Interview for Cognitive Status was used for cognitive screening. Results: 15 persons with dementia, 15 informal caregivers, and 14 dyadic discrete choice experiments were conducted. The majority of persons with dementia (53.3%) was able to complete choice tasks including two scenarios characterized by three attributes and completed on average 6.4 (SD 4.1) choice tasks before dropping out. The dyadic DCEs enabled persons with dementia to complete surveys that were somewhat more complex, and on average a higher number of choice tasks (7.9, SD 3.9). In the dyadic DCEs, informal caregivers assisted the person with dementia to understand the choice task, elicited choice motivation, and provided the means to discuss each other’s preferences. Conclusion: Persons with dementia that have a mild to severe cognitive impairment can use discrete choice experiments with low choice task complexity. Dyadic DCEs can enable greater empowerment of the person with dementia while promoting joint decision making. Future work should further explore the mapping of severity of dementia and feasible choice task complexity, to enhance our understanding about designing choice elicitation tasks.