Usability and adherence evaluation of a smartphone app for home-based symptom monitoring of cervical dystonia

Background: Cervical dystonia (CD) is a movement disorder that is characterized by involuntary muscle contractions causing abnormal head postures. Current assessments rely primarily on infrequent clinical evaluations and subjective patient-reported outcomes (about every 3 to 4 months), limiting detailed understanding of symptom progression between treatments. Objective: Improved understanding of symptom progression would enhance personalized treatment with Botulinum toxin A therapy. For this purpose, we introduce Move2Screen, a smartphone application designed for frequent home-based, asynchronous video monitoring of symptom progression for CD patients. We evaluate the usability and adherence of Move2Screen. Methods: Adherence was assessed in a longitudinal home-based observational study involving eight from initially 11 patients with CD who continued participation after the initial on-site acquisition. Usability was measured using the German mHealth App Usability Questionnaire (G-MAUQ) after the two-week mark, which evaluates ease-of-use, interface satisfaction, and usefulness. Adherence was analyzed by tracking the frequency and timing of recorded videos. Results: The app showed good overall usability scores on the G-MAUQ and a high adherence rate, with participants completing 74% of the intended video recordings. However, usability evaluations highlighted some challenges in perceived usefulness and minor technical issues reported by users. Conclusion: The Move2Screen app demonstrates promising usability and adherence for home-based symptom monitoring in CD. However, addressing technical limitations, expanding participant cohorts, and integrating clinical decision support are essential next steps. These developments may enhance individualized care by enabling more informed therapeutic adjustments and improving long-term disease management.