All products designed for human use must account for the specifics of its users. Everything from physicality to emotional state can influence the success of a product or its failure. This is especially true in medical device design, where products are intended to save lives and treat debilitating illnesses. Considering the human element, utilizing the study of usability research and human factors is crucial to ensuring quality of care and preventing avoidable health and safety risks. In this series, we will take a deep dive into the intricacies of how Usability Research, Human Factors Engineering and User Interface Design impacts the development and performance of medical devices, from examination and implementation down to evaluation, usability, and regulatory requirements.
Human Factors: Definition and Importance
It is a common misconception that "human factors" refers exclusively to the physical characteristics of a device’s user. While anthropometry, the measurement of the human body's size, form, and function, is an essential ingredient of human factors, the principle itself includes the study of a wide range of factors that influence the usage ceremony of a device beyond the physical human machine interface (HMI). Numerous disciplines and methods are employed in the practice of usability research and human factors, assessing the psychological, intellectual, and environmental aspects of a device's user, as well as conditions of use, applications, and more. Overall, usability research and human factors engineering touches all aspects of the user and use environment of which impact the safety and efficiency of a medical device. MIDI applies this information to the design itself to encourage successful usage and mitigate potential safety risks and device failures. While this practice is crucial to producing an efficient, safe, and effective device for users, our quality methods also ensure that regulatory requirements set forth by bodies such as the FDA are adequately met.
A device that has successfully accounted for usability and human factors will be easier to use and possess more readily understood instructions, readings, controls, and displays. Such devices will also provide safer connections between the device components and accessories to guarantee successful periphery use and better evaluation of patients' current health status. Meanwhile, the device will also feature reduced risk of use errors, unforeseen adverse events, and product recalls. For example more effective alarm systems, adjusted to use environment and the user's physical capabilities, allow clinicians to recognize and respond to emergencies simply and quickly. Maintenance, repair, and operation are also made more comfortable by accounting properly for usability and human factors.
The Three Components of Usability Research & Human Factors Study:
But how are usability and human factors evaluated? The study of UI/UX and human factors when applied to medical devices has three primary components.
Component One: The Device and Device User
The first component to consider is the device user or users themselves. User groups of a particular device can vary significantly in capabilities, medical knowledge, and intellect. One group may consist of medical providers such as physicians, nurse practitioners, occupational therapists, social workers, home care aides, and nurses. Another group might include non-professional operators such as the patient themselves or their caregivers, who may be a family member or friend. In some cases, the user group might be consistent with children who operate the device under supervision or with a guardian's assistance. User groups may also include medical personnel like radiologists and lab technicians, and professionals who install, set up, clean, reprocess, or perform maintenance and repairs on the device.
Per the FDA, every user group of a particular device should use the device without risk of use errors that may compromise the quality of care or patients' and users' safety. Ensuring that this is the case means performing studies to determine a user group's ability to operate the device which addresses many factors. These factors include physical size, strength, stamina, dexterity, flexibility, coordination, sensory skills such as hearing, vision, tactile sensitivity, and cognitive abilities like memory. Also included are aspects such as the patient's general health status, the condition they are being treated for, and any comorbidities they may possess. Additional considerations can be literacy, language skills, level of education, health literacy and familiarity with the device or similar devices. It is also important to assess the ability, willingness, and motivation of a user to learn and adapt to a new device or system.
Component Two: Device Environment
The second consideration is the environment in which the device will be used. The device environment may possess several vital factors that could significantly impact operation and performance within clinical and/or non-clinical settings. In uncommon cases, a use environment may be an uncontrolled setting or even within a moving vehicle. One example of environmental condition that would be subject to study is lighting level. Low or high lighting can influence the ease of which a device's display or controls are viewed. Ambient noise is another example, impacting whether alarms and other operational feedback can be heard or distinguished from one another.
Another environmental example is the level of activity, clutter and equipment in a particular setting. All of these examples and more may influence the efficiency of user interaction, device maneuverability as well as the user's mental state, making them confused or unfocused. For example, an environment setting such as a moving vehicle, vibration and motion may impact a user's fine motor skills and visual ability to read and interact with a device's Graphical User Interface (GUI).
Component Three: Device User Interface
Finally, the third primary consideration of usability and human factors is the device user interface. As the main point of contact for essential interactions between the device, user and patient, the user interface is a natural manifestation of the observations and data collected in the Usability Research study of the previous two components. Usability considerations and HFE are collected and applied for device setup, including unpackaging, calibration, device maintenance, cleaning, battery or part replacement, and usage within the care setting. One aspect of the user interface that has a direct affect on HMI is the device's size and shape, particularly in handheld, wearable devices or disposables. Information delivery elements, such as indicator lights, displays, and auditory and visual alarms, are another example. Also included is the cognitive logic workflow of the overall user-system interaction, composed of how, when, and what form the information or feedback is delivered. Other factors include hardware control components like displays, switches and buttons, accessories, peripherals, and packing and labeling, including instructions for use (IFUs), training manuals, and other informational materials.
Methods of Evaluation and Implementation
Human factors engineering is an area that spans numerous disciplines and employs a wide range of techniques to evaluate usability and implement human factors engineering into a device’s design. Contextual immersion studies, voice of the customer capture, formative and summative evaluation studies, and cognitive walkthroughs are part of usability research and human factors engineering activities as related to user-related risk evaluation, analysis and control. Once teams have observed and documented the usability and human factors components necessary, they must take that content to reflect and direct into the device design implementation.
At MIDI, the study of how a design influences interactions, relationships, and usage ceremony is of utmost importance. Studies are performed by MIDI's Usability Research, Human Factors and Design teams who work in close support and collaboration with our software, engineering and IoT development groups. Using advanced Usability Research and HFE Methods supported by MIDI’s AGILE quality development process affords insight that leads to generating medical device innovation for our clients within rapid timelines, while meeting stringent regulatory requirements.
Look for the next part of our series, where we will discuss the regulatory guidelines and standards required.