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The world of medical technology never stands still, and at the heart of this relentless development is the indispensable need to continuously improve the safety and effectiveness of medical devices. A shining example of this progress is the usability lab designed by USE-Ing. at the STIMULATE research campus. This initiative is not only a testament to technological innovation but also to the fruitful collaboration between renowned institutions and companies.

Innovative collaboration for forward-looking solutions

The creation of the usability laboratory with a focus on iMRI (interventional magnetic resonance imaging) is the result of the joint efforts of Otto von Guericke University, USE-Ing. GmbH and Hannover Medical School. This specialized environment was developed with the aim of addressing the unique challenges and requirements of interventional radiology. Equipped with a simulated interventional room, an interactive MRI model, a control room and an observation room, the lab provides a comprehensive platform for studying clinical workflows, identifying challenges and improving the usability of medical equipment.

Success through partnership & technology

A recent interim evaluation as part of the BMBF-funded STIMULATE research project has proven the efficiency of the laboratory by demonstrating its ability to simulate MRI-assisted liver biopsy procedures as an exemplary use case. This success was made possible by the collaboration with renowned partners such as the University Medical Center Magdeburg, BEC GmbH, RAYDIAX GmbH and IGEA S.p.A.. Their expertise and dedication not only made this development possible, but also made it extraordinarily fruitful.

Our role as USE-Ing. & the importance of usability tests

We at USE-Ing. see ourselves as a key player in this project, as we were able to demonstrate our expertise in the field of human factors and usability engineering. The combination of quantitative measurement methods such as eye-tracking and motion-tracking, paired with classic usability test methods, significantly shaped the evaluation objective. The innovative character was additionally reinforced by the collaborative evaluation concept, whose true added value lies in the mapping of real workflows. Several test subjects, a radiologist and a radiology assistant, went through the usability test and their respective collaborative tasks in parallel. This orientation has a massive influence on the test design and the work of moderators and note-takers.

By providing comprehensive services ranging from context of use analysis, usage risk analysis, user interface design and user interface evaluations, we are compliant with relevant standards such as IEC 62366 and ISO 14971. These services are critical to ensuring the safety and effectiveness of medical devices, minimizing risks and ultimately improving patient care.

Future prospects & the potential for further innovations

The usability laboratory at the STIMULATE research campus and the involvement of USE-Ing. impressively demonstrate how research, development and practical application can go hand in hand. This project serves as a model for future research and development projects and offers a glimpse of what can be achieved through collaborative usability tests in the future.

The successful implementation of this milestone at the STIMULATE research campus underlines the importance of collaboration between science, industry and medical institutions. It is living proof that by combining expertise, commitment and innovative technologies, the boundaries of what is possible in medical technology can be constantly expanded. We would like to thank all our partners, especially VDI Technologiezentrum GmbH for their exemplary management, for their contribution to this success and look forward to continuing to work together to set new standards and drive innovation and report on this in the near future.

STANDARDS & REFERENCES

• Show Case Video: Collaborative Usability Testing
• IEC62366-1: Teil 1: Anwendung der Gebrauchstauglichkeit auf Medizinprodukte (IEC 62366-1:2015 + COR1:2016 + A1:2020); Deutsche Fassung EN 62366-1:2015 + AC:2015 + A1:2020
• DIN EN ISO14971: Medizinprodukte – Anwendung des Risikomanagements auf Medizinprodukte (ISO 14971:2019); Deutsche Fassung EN ISO 14971:2019 + A11:2021

IRNAS and USE-Ing. have officially announced their partnership to develop innovative and user-centric solutions for various industries. The two companies are pooling their resources to promote sustainable and long-lasting solutions that are tailored to the needs and workflows of users.

With a broad spectrum of industries and sectors, including consumer goods, medical technology, and security technology, USE-Ing. and IRNAS will jointly shape the future of the industry.

Experienced team develops user-centric solutions with IRNAS partnership

USE-Ing. is composed of an interdisciplinary research and design team of experienced usability engineers, psychologists, HMI, and UX designers. This team has developed a deep understanding of users and their needs in their professional everyday life and is capable of identifying and addressing technological challenges to ensure a better user experience.

The unique combination of in-house manufacturing and multidisciplinary engineering experts with comprehensive experience in building devices using rapid prototyping methods allows IRNAS to develop cost-effective and time-optimized solutions for various industries. The solution design that enables an intuitive user experience significantly increases satisfaction and product success.

Both our companies are based in Europe, but they offer their products and services on the global market, assisting some of the largest companies in the most demanding sectors in the introduction of innovative solutions.

About the companies USE-Ing. and IRNAS

USE-Ing. GmbH is a German human factors engineering and design service company with the mission to develop technology for and especially with users. Since 2018, USE-Ing. has become a renowned provider of professional services in the fields of human-centered product development, UX/UI design, ergonomics, usability optimization, and user-centered innovation. Involving real users at the right time and in the right way in the product development cycle is our distinguishing feature in the market. In the context of digitalization, automation, and demographic change, we support industrial companies from medical technology, aviation, and mechanical engineering in the user-friendly design of products. That’s why USE-Ing. recruits professional users who co-design and evaluate high-tech products throughout the entire development process, thus ensuring that “the right thing is built before it’s built.” 

IRNAS is a custom hardware development company based in Maribor, Slovenia. Since 2011, IRNAS has evolved into a visible, well-established design house covering many industrial areas. IRNAS offers electronics engineering, firmware development, software development, prototyping, and automated testing, as well as design for manufacturing and production management. With its constantly evolving in-house production capabilities, IRNAS ensures that it remains one of the fastest design and prototyping companies in this part of the world. IRNAS is one of the few EU-based design partners of Nordic Semiconductor and develops specialized solutions with BLE and mobile connectivity. In the past two years, IRNAS has also focused on becoming an expert in the integration of machine learning in devices. Their expertise in this area has been further advanced through a development partnership with Edge Impulse.

We are happy to support you holistically and user-centered in your development process. If you are interested, our experts are at your disposal with advice and action. Get in contact

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Since the introduction of the Medical Device Regulation (MDR), the examination of usability has become a focus for manufacturers of medical devices. At the heart of the so-called human factors or usability engineering process are user interface evaluations of medical products with medical professionals.

Medical progress and the innovative power of medical technology developers lead to an increasing number of interaction processes between people and technical, stationary, as well as ambulatory systems; from the perspective of the medical user as well as the treated patient. Here, the patient is usually not the user of the device, which is why medical devices typically have two interfaces to people. This interaction relationship represents the human-machine system, in which the system elements patient, doctor (or nurse), and machine are related to each other through interactions.

Due to the increasing use of innovative technical systems, new requirements arise from the user’s point of view in terms of safe, effective, efficient, and satisfactory operation of medical technology. The collection, implementation, and validation of these so-called usage requirements, alongside the design of user interfaces (User Interfaces) and their evaluation, are the focus of the “Usability Engineering Process”. In the development of medical devices, in addition to these components known from “User Centered Design,” the risk management of use-related risks (Use-related Risk Assessment) is an essential aspect.

Regulatory and standard requirements of the Usability Engineering Process

The establishment and implementation of a Usability Engineering Process and the documentation of all activities in a Human Factors or Usability Engineering File are part of the regulatory requirements for manufacturers of medical devices in the context of medical device approval. The normative references for usability engineering form, from a German perspective, DIN EN 62366-1:2021 and IEC/TR 62366-2:2016. The American Food and Drug Administration (FDA) raises additional regulatory requirements and presents them in its guideline document FDA-2011-D-0469 (Applying Human Factors and Usability Engineering to Medical Devices). Further requirements apply for China and the UK.

From the uss specification to user requirements engineering to use risk analysis

The specification of the application (Use Specification) represents the starting point of the Usability Engineering Process. This includes, among other things, the intended medical indication, the specification of user groups (User Profile), and the specification of all relevant usage environments. The specification of the application (Use Specification) already influences the later evaluation activities, for example, in the selection of representative test participants or test environments for the summative usability evaluation. The identification of user tasks and requirements in empirical studies of the usage context (User Research & Workflow Analyses) forms the bridge to the subsequent steps of use risk (Use-related Risk Assessment) and user requirements management (User Requirements Engineering). In the risk management process, use-related risks are analyzed and assessed based on task models. In the requirements management, the requirements necessary for the design of the human-machine interface (User Interfaces) are derived from the needs.

User Interface Design

The subsequent phases of design and evaluation are based on risk and requirement considerations. In the User Interface Design phase, all human-product interfaces (User Interfaces) are specified within the User Interface Specification and designed using prototyping methods. Depending on the nature of the medical device to be developed, various prototyping methods can be used. For example, 3D printing and laser cutting methods are suitable. The assurance of usability (Usability) of the developed User Interface prototypes is done using targeted usability evaluation methods.

User Interface / Usability Evaluationen

Usability evaluations form the heart of the Usability Engineering Process and must be planned early on. Here, the scope, type, and timing of the evaluation methods must be adapted to the complexity of the medical device to be evaluated, not only to prove the regulatory obligation of safe and effective handling but also to enable the actual added value, the desired optimization of human-product interaction. Usability evaluation methods can be divided into inspection and user test methods.

Inspection methods are carried out by usability professionals and mostly involve checking compliance with heuristics or design guidelines. Here, experienced experts check the user interfaces of the medical device for conformity or deviation with existing and recognized guidelines. In the context of medical device development, thinking through operating procedures (Cognitive Walkthrough) is also used as an inspection method.

In contrast, the second group of methods, the user test methods, follows an empirical, user-based approach. For this purpose, it is necessary to simulate the usage context sufficiently in the usability lab and to carry out observations and interviews with users representative of the respective medical device. The gold standard test method is the Usability Test, an evaluation of usability with users based on simulated task scenarios (Test Cases), usually with participant observation.

In the Usability Engineering Process for medical devices, methods from both groups are described in the normative references. Since inspection methods involve less implementation effort, they are recommended for early phases when the user interface is not yet sufficiently concrete for a Usability Test. When which method is used must be determined in the User Interface Evaluation Plan at the beginning of the design activities. Crucial are the early planning and methodically correct implementation of the evaluations.

If evaluations are carried out accompanying development, they are called formative evaluations. Here, the focus is on identifying optimization potentials of the human-medical product interaction and their design-technical reflection in the development process. The normative references recommend conducting several formative evaluations. Depending on the complexity, novelty, and risk profile of the user interface, two to three formative evaluations are advised.

At the end of the medical device development process, manufacturers are obliged to prove the safe and effective use of their medical device. This is done within the framework of summative usability validation or evaluation. The summative evaluation includes a normatively determined type of planning (Evaluation Plan) and documentation (Evaluation Report).

Conclusion

Medical Human Factors & Usability Engineering serves both to meet regulatory requirements and to identify market-differentiating optimization potentials. In this respect, the interlocking of usability evaluations with the application specification (Use Specification), risk management (Use-related Risk Assessment), and requirements management (User Requirements Engineering) is of the utmost importance and should be anchored interdisciplinary in the entire development team to maximize the benefits.

Do you need support in implementing your medical usability activities? Our USE-Ing. experts are ready for you.

Standards & References

Understanding and properly applying the principles of technical ergonomics and usability

The market for hand-operated tools, from electric leaf blowers to vacuum-mop devices to hand drills, is highly competitive. While German-speaking manufacturers could defend market shares through technical performance a decade ago, international competitors are increasingly catching up in this regard. One of the most promising market differentiation potentials for the future is the user-centered development and design of work tools.

The design of human-tool interfaces, such as handles, operating and display elements, and innovative interaction concepts in the form of gesture and voice controls, are the focus and crucially determine comfortable and intuitive handling. However, for this product class, it is also essential to ensure safe handling for users even in the most extreme working conditions, such as dirt, temperature, or moisture. Manufacturers face the fundamental challenge of systematically identifying user needs from the start, translating these into technically specifiable usage requirements (User Requirements), prototyping them in the form of suitable human-machine interfaces, and ultimately evaluating them with real and representative end-users. These basic steps of user-centered product development should be iterated as quickly as possible according to DIN EN ISO 9241-210. The targeted integration of these sub-processes into the overall technical product development process is also demanding. The basis of user-centered work tool technology is provided by technical ergonomics, the approaches of usability (Engl. Usability), and suitable methods of interface prototyping.

Ergonomic fundamentals of work tool design

According to Schmidtke, “ergonomics is a scientific discipline whose object is the study of human interaction with technical systems”. This also implies the design and development of methods necessary for this research. Technical ergonomics, as further divided by Maier and Schmid, can be divided into macro and micro ergonomics. Macro ergonomics is based on a spatial ergonomics and height grid corresponding to body sizes, defining areas of visual and grasping spaces. Micro ergonomic content concerns the shape, color, graphic, and material design of control elements and graphical user interfaces. The ergonomic design of human-work tool interfaces is based on user-centered measures of anthropometry and the doctrine of comfort angles.

Anthropometric measurement conception

According to Schmidtke, anthropometry is the sub-discipline of anthropology that measures and statistically processes body measurements and proportions, as well as gender-, age-, region-, and socio-specific differences, and interprets them application-oriented if necessary. [2] Percentiles are mostly used for anthropometric data. This information indicates the percentage of the population group studied that falls below or exceeds a certain measurement. The 50th percentile corresponds to the median. For ergonomic designs of human-machine interfaces of hand-operated tools, besides the 50th percentile of the relevant body measure, usually the 5th percentile (female) and the 95th percentile (male) are used. It can be assumed that all users whose body measurements fall between these boundary percentiles can use the resulting product ergonomically satisfactorily.

Comfort angle doctrine

Comfort can be defined as subjectively experienced well-being in a given environment or simply through the absence of discomfort. The measure of comfort or discomfort is especially relevant in the user-centered design of hand-operated tools concerning body posture and the position of body parts or joints during operation. [2] From this, the definition of comfort angles as the angles between body parts that are subjectively perceived as pleasant arises.

Failure to maintain comfort angles results in forced postures in the form of unphysiological body postures forced by working conditions. These lead to fatigue and muscle pain after a longer duration due to static holding work. In addition, the perceived level of strain increases, which is the result of psychophysiological reactions of humans to external stresses.

For the design of an ergonomic gripping and operating posture of hand-held devices, the joint chain from the clavicle joint through the shoulder joint and elbow joint to the wrist joint is particularly relevant. In addition to the maximum movement angles, the comfort areas for the upper body and the hand-arm system are important features for a user-friendly design of hand-held products.

Rapid prototyping of physical human-machine interfaces of hand-operated devices

Once the human-machine interfaces have been analyzed and conceptualized using ergonomic methods, the next step is to realize them in prototype form to make the handling and operation tangible for users. Depending on the type of interface to be designed (Engl. Interface), different methods are effective. For example, modular or plug-in systems are suitable for manipulation elements such as guide handles to estimate the basic grip and grasping surface layout. For controls and detailing of handles, plastiline or clay can be used to approximate a suitable shape. To enable test users to experience a product close to series production in the early phases of product development, the use of 3D printing techniques becomes sensible. Once this state is reached, it is necessary to evaluate the usability of the prototype.

Fundamentals of usability evaluation

According to the DIN EN ISO 9241 standard series, usability (Engl. Usability) is the extent to which a product can be used by specific users in a specific usage context to achieve specific goals effectively, efficiently, and satisfactorily. Thus, effectiveness, efficiency, and user satisfaction are quantifiable metrics of usability that can be collected during the operation of the tool, i.e., during interaction with it. Evaluation methods are available for collecting these measurement parameters.

Usability evaluation methods can be divided into inspection and test methods according to Nielsen. Inspection methods are conducted by usability professionals and mostly involve checking compliance with heuristics or design guidelines. Here, an experienced usability expert analyzes the human-work tool interface of the technical product for conformity or deviation from existing and recognized guidelines. For hand-operated tools, this usually includes geometric specifications such as grip diameter or grip materials, as well as application-appropriate grip orientations and courses. In addition, the societal compatibilities recognized in the respective cultural circle and the affordance, the so-called offer character, of the design must be checked. For example, in the Western cultural circle, the green design of a control element is usually associated with the start of a process, while a red color marks the end of a process. The same applies to widespread symbols and icons, which should be considered accordingly in the design.

In contrast to these analytical methods, the second group of methods, the test methods, involves an empirical approach. It is necessary to enter the usage context and conduct observations and interviews with real users. The gold standard test method is the Usability Test, an evaluation of usability with users based on defined task processing, usually through participant observation.

Do you want to develop future-oriented and innovative work tools and devices and are looking for a reliable partner? Our experts in user-centered technology development and design are ready to assist you in this challenge.

STANDARDS / REFERENCES