The Duchenne muscular dystrophy (DMD) Video Assessment requires a caregiver to record six videos of their ambulatory child performing physical activities using a smartphone application (app). Innovative assessments that combine a performance measure, technology, and an observer require new approaches to content validation studies. This study presents a novel approach to establish the feasibility and content validity of the Video Assessment and usability of the app.


Interviews used concept elicitation and an adapted cognitive debriefing approach. Interviews were conducted with 8 clinicians who reviewed training materials prior to the interview and provided feedback on the appropriateness and usefulness of the DMD Video Assessment and the relevance of the physical activities. Four caregivers reviewed training materials and used the app to record their child performing the physical activities prior to the interview. Researchers reviewed the recordings against a checklist to identify discrepancies in caregivers’ understanding of the training materials prior to an interview. During the interview, caregivers commented on comprehension of the materials, appropriateness of the activities, and feasibility of recording the videos.


Clinicians found the DMD Video Assessment and materials appropriate and useful for assessing disease progression and treatment response. Caregivers found the activities appropriate and the training materials and app easy to understand and use. Feedback resulted in changes to the training materials, but not the activities or videotaping procedure.


Researchers used an innovative methodological approach that adapted traditional methods of content validation for the purpose of evaluating a technology-based performance measure in its totality. While future studies should be conducted with a larger, more diverse sample, these study findings add to our understanding of the content validity of the DMD Video Assessment.