Evaluation of an audio-based monitoring system for detecting retching and vomiting in gastroparesis: an observational cohort study

This study aimed to evaluate a novel, audio-based digital monitoring system for detecting retching and vomiting (expulsion) events in a noninterventional, longitudinal study involving 25 participants with gastroparesis (GP). Participants used an audio-based system comprising an iOS device (iPhone) and Watch in their home environments for approximately 14 days. Retching and expulsion events were quantified using human-annotated counts from audio recordings and daily electronic patient-reported outcome (ePRO) counts. Device compliance was defined as the percentage of expected recording time successfully captured over the 14-day study period, calculated as recorded hours divided by the total expected hours (24 × 14). Compliance was high overall, with a mean rate of 83.4% for the iOS device and 69.4% for the Watch. Event timing analyses from the audio devices revealed elevated retching and expulsion activity in the morning, with symptoms persisting during nighttime hours. Strong correlations (r > 0.85) were observed between event counts from the Watch and iOS devices, although the agreement of device counts with ePRO counts was lower (r < 0.40). While ePRO-based expulsion counts showed a stronger within-participant correlation with patient global impression of frequency/severity (PGI-F/PGI-S) measures, device-based counts were better at distinguishing between participants across different PGI-F/PGI-S levels. Weekly averaging of event counts improved consistency across both audio-based and ePRO measures relative to daily event counts. These preliminary findings suggest that audio-based technologies offer an objective, sensitive, and scalable approach to detecting vomiting and retching in episodic disorders, with strong potential to support remote patient monitoring, real-world evidence generation, and earlier proof-of-concept evaluation in clinical trials for gastroparesis and other episodic vomiting disorders.