Cocreation of Digital Outcome Measures for Dravet Syndrome: Multistage Co-Design Feasibility Study.

Background: Dravet syndrome is a complex developmental and epileptic encephalopathy characterized by treatment-resistant seizures and multiple comorbidities that significantly affect quality of life. Traditional clinic-based assessments often fail to capture real-world functional abilities and behavioral changes. Objective: This study aimed to (1) identify caregiver-prioritized meaningful aspects of health, (2) co-design digital assessment modalities for home use, and (3) generate preliminary usability and implementation insights to inform future clinical research. Methods: A multistage patient and public involvement activity was conducted between November 2023 and October 2025 in Spain, in collaboration with a patient advocacy organization and a digital health company. Participants were recruited through the Fundación Síndrome de Dravet using a convenience opt-in sampling approach. The process included a caregiver survey to identify meaningful aspects of health, a design workshop to refine priorities and technology preferences, and a 2-week usability testing of a prototype app, followed by a feedback workshop. Data were analyzed descriptively to inform iterative cocreation; no hypothesis testing was performed. Results: Fifty caregivers completed the survey. Neuropsychiatric symptoms (17/48, 35%), independence (16/48, 33%), and social or leisure activities (15/48, 31%) were the most commonly reported affected domains. Eight caregivers participated in the design workshop, emphasizing flexibility, age-appropriate tasks, and reduced reporting burden. Usability testing was conducted with 5 caregivers over 2 weeks, with 4 of 5 caregivers providing feedback. Participants reported a generally positive reception of the digital tools, particularly customizable task selection and open-text fields, while identifying challenges related to video-recording logistics and questionnaire repetition. Feedback underscored the need for simplified workflows and individualized approaches to maintain engagement. Conclusions: Cocreation with caregivers is feasible and appears essential for developing meaningful digital outcome measures for Dravet syndrome. Video-based tasks and remote reporting tools show promise for capturing motor, cognitive, and behavioral domains beyond seizure frequency. Future work should focus on iterative refinement and formal validation of these measures as end points in clinical trials, ensuring that they reflect outcomes that matter most to patients and families.