Heuristic Evaluation of a Medical Device Prototype

Usability principles are often secondary to clinical effectiveness when assessing medical devices. However, the majority of medical device incidents are linked to user error. Greater attention to usability evaluation during the development of a medical device can prevent patient-endangering errors. In this study, the usability of a medical device prototype is assessed through heuristic evaluation. The aim was to carry out an evaluation and to assess heuristic evaluation as a method to improve medical device usability. The evaluated prototype is a mobile eye blink pacemaker aimed at patients with unilateral facial palsy. Facial palsy impairs the muscles responsible for producing the eye blink. Lack of blinking can result in complications such as dry eye disease and corneal ulceration. The purpose of the studied prototype is to evoke the eye blink with electrical stimulation. The device could be a simple and cost-effective alternative for more invasive methods. Heuristics targeted particularly for medical devices are yet to be developed. Heuristic applied in this study are a combination of heuristics formerly used in other studies analyzing medical devices. The majority of usability problems detected concerned the user’s control and physical effort. The most severe problems were related to error situations. Most of the heuristic violations were rated as minor problems; no catastrophic problems were found. The most problematic part of the prototype was the adjustment of the stimulation level. The heuristic evaluation is a quick and resource-efficient method to identify usability problems and their severities in medical devices. However, more research is needed to create a standard set of heuristics aimed especially at medical devices