Shortly before the coronavirus crisis restricted our public life, two of our employees from the Industrial Design and UI / UX Design departments were able to undergo further training in the field of usability engineering in medical technology in Tuttlingen, the "world capital of medical technology". In the Innovation and Research Center building on the IFC university campus, our employees were able to deepen their existing knowledge in lectures and exercises and gain new insights for our daily work on medical products for our customers. The active exchange with other experts from various areas of medical technology on current standards and developments as well as personal experience in development projects is also always valuable for our daily work.
The human-centered design process from DIN 9241 has been an integral part of our UI / UX development process for years. For good usability, it is important that users can achieve their goals effectively, efficiently and satisfactorily while using a product. The user experience also considers the areas before and after use. Application errors can be avoided through good design.
A medical device often has several different human-machine interfaces, such as manipulation elements (actuators), display elements (e.g. displays) and presentation elements (e.g. supports); they are operated by different personnel with sometimes different tasks and objectives, are intended to be distributed and used internationally and are subject to strict legal requirements as part of the approval process.
An error in the use of a medical device, e.g. in a clinical context, can have serious consequences and, in the worst case, lead to the death of the patient. The usability engineering process is therefore rightly of particular importance here.
From a regulatory perspective, the creation of a usability file has been necessary for CE approval since 2007. Since 2015, with the introduction of IEC 62366-1:2015, proof must be provided that the usability engineering process has been carried out. IEC 62366-1 describes the mandatory minimum with a focus on effectiveness and safety, while IEC 62366-2 describes the recommended usability with the addition of efficiency and satisfaction. The human factors engineering process is prescribed for approval by the FDA. The EU Medical Device Regulation 2017/745 (MDR) replaces the Medical Device Directive (MDD) Directive 93/42/EEC and Active Implantable Medical Devices (AIMD) Directive 90/385/EEC. For usability engineering, this means an increased focus on post-market surveillance, more detailed requirements for the usability engineering file, changes to the classification rules, increased testing of the usability engineering process for all medical device classes and increased transparency and traceability.
In addition to compliance with legal requirements, usability is a differentiator from the competition and improves customer satisfaction and customer loyalty and can also reduce costs in the area of service and user training, for example.
Development process according to the usability engineering process
The usability engineering process includes the specification of the application (use specification), requirements management (requirements engineering), risk management (risk management) and the user interface design and its evaluation.
In our product development process, we first deal with the use specification and analyze the context of use and record users and user groups (from primary, secondary and indirect users to various stakeholders) with their context of use, tasks and goals. In use cases, we record the various work tasks of the users, broken down into core and subtasks, and create use cases with an actio/reactio approach that also include the system response. On request, we can also create usage scenarios with PCA analysis (perception-cognition-action analysis) to identify potential interaction problems. These usage scenarios can then serve as the basis for risk management. The risk assessment is based on the probability of a specific use error occurring and on the severity of the consequences (e.g. from temporary minor patient discomfort to death). Potential problems can already be identified on the basis of the user scenarios and risk-minimizing measures can be developed (risk control measures).
By specifying the application and analyzing it, we can formulate requirements, known as user needs, and usage requirements, known as user requirements, for requirements management. User requirements must always be formulated in such a way that the focus is on the user and their needs. They should generally be formulated without a solution. Only system requirements may be formulated in a solution-oriented manner. While system requirements can be verified relatively easily, user requirements for medical approval must be validated via a usability test.
In the formative test series, testing and validation can still be carried out very freely. We recommend iterative testing early on in the development process in order to identify potential problems as early as possible and develop appropriate solutions and risk-minimizing measures. Especially at the beginning of product development, necessary adjustments can be implemented much more cost-effectively than at a later stage. We also support our customers in the preparation, implementation and documentation of usability tests and produce the necessary physical and digital prototypes.
While the first prototypes are still simple and can, for example, be limited to their basic functionalities, the product designs at Busse Design + Engineering become more and more detailed during the development process and are optimized based on the test results.
As a professional service provider in the fields of industrial design, UI/UX design, construction and prototyping, we examine the product not only from a regulatory perspective, but also primarily from the perspective of the target group, the market, the brand and production. The result is not only well thought out from a regulatory perspective, but also innovative and forward-looking.
Through our creative design development, we set new design trends, shape the brand image and create a high recognition value. We increase the value of products and can simultaneously save costs in production, training, assembly and service by optimizing user interfaces, components, tools and production processes.
We also map the design development from industrial design and UI/UX design, as well as the constructive development in our physical and digital prototypes, check them in the formative tests and can continue to optimize and refine them.
The summative test at the end of product development is where things get serious. Test cases are derived from the existing user scenarios and acceptance criteria are defined. Hazard-related user scenarios must then be tested with representative users and a close-to-production prototype. The acceptance criteria must be met.
We are also happy to support you in the development of your medical products with our expertise in industrial design, construction, UI/ UX design and prototyping.