Medical Devices: User-centered Design for More Safety

Photo: Alexander Steffen

Alexander Steffen; © User
Interface Design GmbH

A person’s health depends on medical devices, which is why their usability has to be as intuitive and risk-free as possible. This is particularly important when patients or family members use the equipment at home. In the user-centered design process, which is at the heart of usability engineering, users are intimately involved in the development of a product. spoke with Alexander Steffen from the User Interface Design GmbH. As Director of Medical & Pharma Solutions, he oversees projects pertaining to the design of medical device user interfaces. Mr. Steffen, what is usability engineering?

Alexander Steffen: Usability engineering is a user-centered design process aimed at product usability. When we design a product, meaning when we provide a user interface and an operating concept for an innovation, we first define the usability requirements: what user groups are there and what main operating functions do they perform? What training and motivation do they have? How much do they use the device on a daily basis?

After this analysis phase, we think about the interaction concepts that being the operating procedures of the device during the design phase. Based on usability requirements, we determine for instance where the operating controls should be. We implement this during the third phase, the prototype build. Usability testing is done during the fourth phase. The usability engineering process is specified in ISO 9241210, but there are also specific regulatory guidelines for medical device design of course. What is the medical safety design process that your company developed?

Steffen: The development of medical devices was and is driven by risk reduction, risk control and risk avoidance. In the past, medical device manufacturers have only seen the product through risk management glasses. If you weren’t able to harm a patient with the product, it was fine. However, sometimes the result wasn’t usable. Today, a medical device has to be both: risk avoiding and usable. The medical safety design process brings risk management and the usability process together. How can users, health care personnel as well as patients, be practically incorporated into the design process?

Steffen: By now, patients and their family members are also users. Since they are not trained, you need to create very safe usability concepts that also provide the user with a sense of security. We include the user at different points in the process by visiting physician practices, hospitals, nursing homes and patients at home for instance and by looking at how the device is being used. During these location visits, we create a so-called usability context analysis.

During the design phase, we then apply a method called cognitive walkthrough. We present a user with the rough draft of a design. This does not need to be a functional prototype; a printout of a screen or a 3D model is enough with which you can already ask the user what response he/she expects if he/she presses a specific button. With the help of this usability method, you can find out a lot about the first draft at an early stage in the design phase without actually having to first finish the design.

Photo: MeMo Tray

The MeMo Tray supports people with early forms of dementia in their daily routines. The screen reminds about appointments, the tray is designed to hold important items like wallet or keys; © User Interface Design GmbH Your company has developed the MeMoTray with a user-centered process, which is designed to support dementia patients in their daily routines.

Alexander Steffen: The MeMoTray is currently still a prototype and not a finished product. For the design and development, we have visited people with early forms of dementia in their homes and watched how things look there. We found notes as reminders for instance, which were pasted somewhere by relatives as well as a central spot in the home where important items such as wallets or keys are being placed. The MeMoTray is a technical aid that ideally links the components and equipment in the home and structures the daily routines by providing calendar information and by reminding people about appointments. The front door will not close for instance, if the key is still in the MeMoTray. This system assists people with early forms of dementia in their daily routines. How did the users directly influence the development?

Steffen: We have worked with an association and a member of the Dementia Competence Network, who has provided many useful contacts and explained a lot about usability requirements. During the home visits, we noticed for instance that nobody wants to use a so-called age-appropriate phone. This is why we decided on a universal design that is suitable for all users. It merely especially supports dementia patients in specific usability contexts. This is less stigmatizing and does not ostracize the patients. What advice do you give researchers and manufacturers who want to design a user-centered medical device?

Steffen: The single most important factor is to consider usability early on at the beginning of the product development. You need to define the main operating functions very early on and know the application specifications, meaning the details about the user groups and usability contexts.

The interview was conducted by Timo Roth and translated by Elena O'Meara.