Detectability and acceptability of continuous pulse signals for the MemoPatch® device, an electronic skin patch intended to deliver tactile medication reminder signals

BACKGROUND Unintended forgetfulness is the most common cause of medication nonadherence. MemoPatch(®) is an electronic skin patch intended to deliver discreet tactile medication reminder stimuli. This study aimed 1) to evaluate, within an experimental setup, the detectability and acceptability of fifteen continuous bipolar pulse signals; 2) to identify variables, if any, associated with differential perception of the candidate reminder signals; and 3) to collect safety data as reported by subjects or observed by staff. METHODS This was a laboratory experiment involving 147 healthy adult volunteers (55.1% female, 98.0% Caucasian, with age 41.8±16.0 years, body mass index [BMI] 24.7±4.4, upper body adiposity 28.5%±8.3% body fat, and skin impedance 367.6±140.8 Ω) and using an experimental version of the MemoPatch(®). Following four training signals administered in fixed order, subjects were exposed to a set of fifteen randomly sequenced signals varying in rise and fall time, width, and current, to be rated in terms of detectability ("too weak", "appropriate", or "too strong") and acceptability. RESULTS Ratings of "appropriate" were virtually independent of such variables as sex, BMI, upper body adiposity, and skin impedance at the patch location. Five signals were rated as "appropriate" by ≥67% of subjects and acceptable by ≥95% of subjects, virtually independently of the indicators of interest, and were retained as candidate signals for use in next stages of development and commercialization. Nine adverse events, none serious, were observed in six subjects. CONCLUSION This study yielded five effective and safe candidate signals for potential use in the MemoPatch(®) device, all equally considered to be of appropriate detectability and high acceptability, in an experimental context. The signals were independent from, and therefore highly robust relative to, sex, BMI, upper body adiposity, and skin impedance at the patch site, lending additional generalizability to the signals and hence their potential relevance to broad commercial application.