Connected By Music: Research on music interventions with adults with intellectual disabilities

Summary This thesis investigates the effects and feasibility of active music interventions for adults with intellectual disabilities (ID), particularly those with challenging behaviour (CB), in Dutch residential care. People with ID often face CB, poor executive functioning (EF), mental health issues, and social isolation, all of which impact quality of life (QoL) for both individuals and caregivers. Music interventions have shown potential to address these issues, but evidence in the ID population is limited and methodologically weak. Using a mixed-methods approach, this thesis explores different music formats (group vs. individual; in-person vs. digital), assessing their impact on CB, EF, mental health, self-esteem, and well-being. It includes three parts: 1. A pilot cluster-RCT comparing group music to leisure activities, 2. A COVID-era pilot testing a partly online music intervention, 3. A full cluster-RCT evaluating individual music sessions versus care-as-usual (CAU). Part 1 – Pilot Cluster-RCT Involving 29 adults with mild to moderate ID, this study compared weekly music group sessions to leisure activities. Both groups improved on well-being and EF, but the leisure group showed stronger effects on internalizing behaviour and inhibitory control, especially in younger participants. The music group showed slightly higher self-esteem and reduced frustration, but these differences were not significant. Feasibility testing revealed high enjoyment of the music sessions, though caregiver involvement varied, and EF assessments were often too difficult. The RCT design proved burdensome for both staff and participants. Recommendations included simplifying protocols, tailoring assessments to cognitive level, and using CAU as a comparison group. Part 2 – COVID Study Due to pandemic restrictions, a pilot study tested partially online, individual music sessions. Ten participants received 16 sessions over 10 weeks. While overall feasible, technical issues, caregiver availability, and impairments like poor vision limited online participation. In-person sessions were preferred, offering stronger emotional and musical connection. Still, CB decreased across both formats, suggesting some benefit from even modified interventions. Part 3 – Full Cluster-RCT This study included 97 adults with mild or moderate ID and CB. The intervention group received 16 individual music sessions over 8–10 weeks; the control group received CAU. The music group showed significant reductions in CB, anxiety, and depression, with effects stronger in those with higher baseline CB. No significant differences were found in well-being or self-esteem, and extending sessions beyond 16 did not enhance outcomes. EF assessments showed no intervention effect, and many participants struggled with the tablet-based tasks. Results suggest existing EF tools may not be suitable for this population, especially those with moderate ID. A process evaluation confirmed that sessions were delivered as intended, were well-received, and led to short-term behavioural and emotional benefits. The relationship with the music worker and session personalization were key facilitators. However, sustainability was limited by caregiver workload, lack of role clarity, and minimal post-intervention support. General Discussion The thesis concludes that individual active music interventions are effective and feasible for reducing CB and improving emotional well-being in adults with ID. However, it remains unclear if music is superior to other enjoyable activities. Key success factors include individual delivery, adequate intensity, face-to-face contact, and clear structure. For long-term implementation, caregiver training, time, and organizational support are essential. Future research should refine assessment tools, compare music to other interventions, and explore mechanisms of change, including physiological data and observational methods.