'I think I'd get a lot out of something where my views count and I could help other people' - co-designing a family project-based intervention with people with lived experience of traumatic brain injury.

Background Meaningful engagement with families who have lived experience of traumatic brain injury (TBI) is essential if interventions are to more closely align with their needs. The aim of this study was to co-design a family project-based intervention including people with lived experience of TBI and explore participant experience. Methods People with cognitive-communication disorders following severe TBI, and their family members, were recruited from three Scottish brain injury services. The co-design teams participated in Microsoft Teams focus groups (October 2022 to January 2023). A range of adapted communication tools were developed to facilitate the co-design process, and e-surveys about the co-design experience were completed. Qualitative data arising from the focus groups were analysed thematically, and survey data were analysed descriptively. Results Thirteen participants (6 people following TBI and 7 family members) attended the co-design groups. The concept of a family project-based intervention was positively received and adaptions to content identified: inclusion of real-life examples, family support resources and a toolkit of strategies. A range of perceived personal benefits of being involved in the co-design groups was also reported; peer support, feeling heard and helping others. Conclusion People with cognitive-communication disorders following severe TBI, and their families, can make a valuable contribution to co-design research and benefit from the process. Following development of the adapted content, progression to the next design stage will involve feasibility testing of the co-designed family project-based intervention.