User-Centered Design For Medical Devices

September 10, 2012

By Dean Hooper, Senior Human Factors Engineer

Excerpt taken from Dean’s article on MDDI Online:

The FDA and international standards bodies have long recognized that use error committed during interactions with medical devices negatively influences patient safety. In many cases, these errors are the result of poor design. The regulatory pressures are increasing to demonstrate that products are safe and easy to learn and use. Given the recent addition of the human factors discipline to the Office of Device Evaluation (ODE), the medical device industry is in a state of flux. For some devices, a development program may just be nearing transfer to manufacturing only to be halted by new, user centered design requirements for regulatory submission, i.e., a usability validation study. This article will provide solutions for meeting newer FDA requirements for validation studies without mandating that a client start anew or lose too much development time.

If user centered design activities have not been conducted during the development process, there is risk that the design is not conducive to consistently safe use. However a sound validation study is still possible if it includes the relevant users and testing scenarios to ensure the method follows FDA guidelines. Using the tools discussed here, some risk to the project can be reduced. The goal is to determine the prerequisites (e.g., user profiles, safety related functions and intended use environment) for a successful submission of a validation study.

This article will also cover good practices for meeting these requirements from the start of a program. That is, incorporating the user early and often in the design decision process. The objective is to ensure a user-centered design so that by the time you reach the validation study, all issues and concerns have been addressed. The design is sound so the risk associated with a validation study is minimized.

User Design Comes Full Circle

A high tech culture has a tendency to quickly implement technologies for the good of society and the bottom line. First to market is key; and first is defined as the latest gadget, not the latest, usable gadget. In this environment, knowing the customers (i.e., users) and how they might interact with a product takes a back seat to technology- and resource-centered factors. User-centered design is a remedy for this condition. Considering the users’ needs and abilities throughout the development cycle is the only way to ensure a product is easy to use and as safe as possible.

The popularity of user-centered design, whether it is due to safety or bottom-line concerns, has ebbed and flowed since its early days in the cockpit design of WWII aircraft. It typically lags just behind technology booms. In a way, the human factors discipline and user-centered product design have come full circle. They began as a necessary process in the design and development of safe machines as they became more and more sophisticated. Then usability research became relegated to offering a competitive edge to manufacturers of consumer products. Now, human factors are again on the front lines in ensuring use error is minimized and safety is maximized in the design of today’s high tech medical devices.

The lockheed p 38 Lightning aircraft from WWII demonstrates user-centered design.
Photo used with permission from

Human Factors and Regulation

Both large and small device manufacturers are being asked by ODE to provide evidence of use error analysis and user-centered design during premarket submissions. However, their respective development processes might not include sufficient human factors input. In many cases a development program may just be nearing transfer to manufacturing or introducing a new product in the U.S. market only to be halted by newly enforced, user-centered design requirements for regulatory submission.

Many device manufacturers share similar regulatory experiences. They have received a review of a premarket submission that states they need to conduct a usability validation study. Others are at the point of submission and need to fulfill the user-testing requirement but have not previously tested the product with actual users.

The only way to be completely sure a product meets the usability requirements for a successful submission is to employ a user-centered design process throughout the development cycle. However, there are strategies for reducing the risk of deficiencies by meeting many FDA guidelines and ISO requirements for usability validation studies without mandating that a client start anew or lose too much development time…