Examining the Wearability and Implementation of Knitted Sensor Garments for Long Term Monitoring of Breathing Health: Thematic Analysis and Sensor Performance Characterization (Preprint)

Abstract

BACKGROUND Long term unobtrusive monitoring of breathing patterns can potentially give a more realistic insight into the respiratory health of people with asthma or chronic obstructive pulmonary disease than brief tests performed in medical environments. However, it is uncertain whether users would be willing to wear these sensor garments long term. OBJECTIVE Our objective was to explore whether users would wear knitted garments with knitted-in breathing sensors long term to monitor their lung health and under what conditions. METHODS Multiple knitted breathing sensor garments, developed and fabricated by the research team, were presented during a demonstration. Participants were encouraged to touch and feel the garments and ask questions. This was followed by two semi-structured, independently led focus groups with a total of 16 participants of which 4 had asthma. The focus group conversations were recorded and transcribed. Thematic analysis was carried out by three independent researchers in three phases consisting of: familiarization with the data, independent coding and overarching theme definition. Participants also completed a web-based questionnaire to probe opinion about wearability and functionality of the garments. Quantitative analysis of the sensors’ performance was mapped to participants’ garment preference to support the feasibility of the technology for long term wear. RESULTS Key points extracted from the qualitative data were: 1) garments more likely to be worn if medically prescribed, 2) cotton vest as underwear was preferred, and 3) a breathing crisis warning system was seen as a promising application. The qualitative analysis showed a preference for loose short sleeved T-shirts with a 81% acceptability rate, a 69% acceptability rate for snug fitting garments and 0% for tight-fitting garments. 62% of the participants would wear the knit for the whole day and 81% only during the night if not too hot. The sensitivity demands on the knitted wearable sensors can be aligned with users’ garment preferences. CONCLUSIONS There is an overall positive opinion about wearing a knitted sensor garment over a long period of time for monitoring of respiratory health. The knit cannot be tight but should be able to be worn as a vest as underwear in a breathable material. These requirements can be fulfilled with the proposed garments. Participants with asthma supported using it as a sensor garment connected to an asthma attack alert system.