Enhancing Adherence to Home-Based Expiratory Muscle Strength Training in Parkinson Disease: Randomized Controlled Trial of an mHealth Intervention.

Background: Aspiration pneumonia is a leading cause of death in Parkinson disease (PD). Expiratory muscle strength training (EMST) is a promising intervention for respiratory and swallowing dysfunction. However, long-term EMST adherence is frequently poor in PD. Objective: This study aims to determine whether mobile health (mHealth)-assisted EMST with the SpiroGym app (Czech Technical University) improves long-term adherence and physiological outcomes versus conventional EMST among participants at risk for nonadherence. Methods: In this single-center, parallel, phase 2 randomized controlled trial, 75 individuals with PD were randomized 1:1 to conventional EMST (control; n=38) or the same protocol enhanced with the SpiroGym app (experimental; n=37), using a simple computer-generated randomization sequence. The SpiroGym is an mHealth app that provides real-time performance monitoring, direct visual feedback, and longitudinal progress tracking. All participants completed 8 weeks of semisupervised intensive EMST with biweekly in-person reassessments, followed by 16 weeks of unsupervised maintenance training. The primary outcome was adherence during weeks 8 to 24 among participants at risk for nonadherence, defined a priori at week 8 as Self-Efficacy for Home Exercise Program Scale (SEHEPS) less than 59. Because risk status was determined at week 8 and all participants subsequently entered the unsupervised phase, individuals not classified as at-risk were not excluded. Their data from week 8 onward were reported alongside the at-risk group. Secondary outcomes were changes in maximum expiratory pressure and SEHEPS. Results: No study-related adverse events occurred. Groups were well matched at baseline (control vs experimental: mean disease duration 7.0 (SD 5.7) vs 7.3 SD 4.7) y; mean Hoehn-Yahr 1.97 (SD 0.6) vs 2.0 (SD 0.5)). The mixed-effects model showed no significant 3-way interaction (group×interval×SEHEPS risk; P=.14). At week 24, the at-risk category for the nonadherence cohort comprised 34 participants (control, n=17; experimental, n=17). In this at-risk cohort, the experimental group demonstrated a smaller decline in adherence during weeks 8 to 24 than controls (β=496.9, 95% CI 130.7-863.3; P=.008), completing 1073 (95% CI 643-1502) expiratory maneuvers versus 525 (95% CI 358-692). Maximum expiratory pressure increased in both groups from weeks 0 to 24, with larger gains in the experimental group (+43.1, 95% CI 32.4-53.8 cmH₂O) than in controls (+22.8, 95% CI 13.8-31.8 cmH₂O; P=.006; Cohen d=0.74). SEHEPS improved after intensive training in both groups, but only the experimental group exceeded the 12-point minimal detectable change at the 95% confidence limit. Conclusions: This is the first randomized controlled trial to integrate mHealth with EMST. Unlike prior studies in the EMST field, we focused on sustaining long-term exercise adherence. SpiroGym-assisted EMST resulted in higher long-term adherence and greater gains in expiratory muscle strength than conventional EMST. In real-world PD care, assessing self-efficacy after the supervised EMST phase may help identify individuals who would benefit from digital support, making mHealth-assisted EMST a practical approach for maintaining exercise adherence.