A process evaluation of the new interventions for independence in dementia study family stream (NIDUS-Family)

The New Interventions for independence in Dementia Study (NIDUS)-Family is an effective Alzheimer’s Society funded manualised psychosocial intervention supporting people living with dementia and their family carers to attain goals they set towards living as independently and as well as possible at home for longer. The aim of this thesis was to conduct a process evaluation embedded into the intervention-arm population of the NIDUS-Family randomised controlled trial (RCT) to understand the causal pathways through which the intervention influenced change.

A systematic review of process evaluation methodology for this population informed the design of the NIDUS-Family process evaluation. The Medical Research Council (MRC) Guidance (Moore et al, 2015) recommendations and a theory-driven convergent mixed-method design were applied. Research questions interrogated the theoretical principles and hypothesised causal assumptions to understand how NIDUS-Family influenced goal attainment and wellbeing in practice through identifying core implementation, mechanisms of impact and contextual factors.

Overall, findings indicated participants positively experienced the NIDUS-Family intervention, describing it as being transformative, supportive, and having a positive impact on their wellbeing and dyadic relationship. Attrition, reach, adherence, delivery, and fidelity data demonstrated NIDUS-Family was delivered as intended against the protocol to its target audience. Core implementation factors were delivery from the facilitator of the NIDUS-Family approaches, strategies, and values. For dyads, mechanisms of impact were building a respectful, trusting, and impartial relationship with their facilitator which aided the development of meaningful goals and/or actions in which they could work through the modules towards finding manageable solutions. Core contextual factors impacting intervention implementation and mechanisms were dyadic participation and knowledge of dementia.

These findings will directly inform the NIDUS-Family implementation study in helping adapt and translate the intervention into practice and widen the knowledge of process evaluation design to ensure more robust applications of frameworks and methods to enable more generalisable outcomes.