Medical Devices: Evidence and Research (Jul 2024)
Quantifying Patient Capabilities and Setting the Stage for Future Development: Insights from a Sensor-Augmented Simulated Use Study with Pen Injectors
Abstract
Jakob Lange, Andreas E Schneider, Christoph Jordi Ypsomed AG, Burgdorf, SwitzerlandCorrespondence: Jakob Lange, Email [email protected]: While formative and summative usability testing is essential to confirm safe and effective product use, it may not be sufficient to comprehensively understand user capabilities and limitations in device interactions. Therefore, this research aims to quantify user handling forces for different device handling steps of pen injectors through sensor-augmented simulated use studies.Research Design and methods: The study involved 46 participants who were divided into two groups: a healthy control group and a group of users with dexterity impairments. All participants were instructed to perform simulated handling steps using non-functional dummy devices equipped with force and torque sensors. Each handling step was performed twice: first at what participants considered a comfortable force level and then at their maximum force. The study then analyzed force data to investigate the impact of user characteristics and device geometry on force exertion during the different handling steps.Results: The study demonstrates differences in the perceived comfortable and maximum force levels between the control and patient groups. These force levels decrease slightly with the user’s age and level of dexterity impairment. Furthermore, the forces applied by the users are dependent on the geometry of the device and the holding pattern.Conclusion: The results highlight the significance of sensor-augmented simulated use studies as a tool for providing quantitative insights into users’ ability to exert force while handling self-injection devices. These data offer comprehensive insights that inform the definition of performance requirements and specifications for injection device design, thereby supporting the advancement of future self-injection devices.Plain Language Summary: This study explores how people interact with pen injectors; devices commonly used for self-injections. Traditional usability tests are vital for ensuring safe product use, but they may not fully capture users’ capabilities and limitations. To address this gap, the research measures the forces exerted by users during different handling steps of pen injectors through a simulated use study with sensors.Forty-five participants, including a healthy control group and individuals with dexterity impairments, engaged in handling non-functional dummy devices with force and torque sensors. Each participant performed handling steps twice, first at a comfortable force level and then at their maximum force. The study analyzed force data to understand how user characteristics and device geometry affect force exertion.Results revealed differences in force levels between control and patient groups, with applied force levels decreasing slightly with age and dexterity impairment. The study emphasized the impact of device geometry and holding patterns on applied forces. Overall, the findings show the usefulness of sensor-augmented simulated use studies in quantifying users’ force exertion, providing insights for designing future self-injection devices.Keywords: subcutaneous drug delivery, pen injector, simulated use, handling force, user capability, force sensor, torque sensor, user impairment
