Usability engineering in practice: developing an intervention for post-stroke therapy during a global pandemic

Figures & data

Table 1. Relevant standards, regulations and recommendations related to usability engineering of medical devices.

Organisation	Role	Example recommendations
Medicines and Healthcare products Regulatory Agency (MHRA)	Responsible for ensuring the safety, quality and effectiveness of medicines, medical devices and blood components for transfusion in the UK	Recommendations on Human Factors and usability engineering during medical device development. Recommend submission of a Human Factors summary report and post-market surveillance for human factors and ergonomic issues [7].
International Organisation for Standardisation (ISO)	Develop and publish international standards.	ISO 14971 [8] relates to the application of risk management of medical devices and is the overarching standard to employ in developing safe and effective devices and, as such, infers an expectation to assess safe usability through the application of related usability standards. The current 2019 3rd edition, increases emphasis on defining the benefit and state- of-the-art of the device as it relates to residual risk, introduced a new definition of “reasonably foreseeable misuse” – (emphasizing the context of such use in assessing whether it can be used safely)- and increased focus on gathering post-market user feedback
International Electro-technical Commission (IEC)	Prepares and publishes international standards for all electrical, electronic and related technologies	IEC (or BS EN) 62366 specifies a process by which a manufacturer can analyse, specify, develop and evaluate the usability of a medical device to ensure safety and mitigate risks associated with correct use, and use errors, within the scope of normal use [9,10]. IEC (or BS EN) 62304 defines the “life cycle requirements” for medical device software and describes a set of processes, activities, and tasks to establish common framework for medical device software life cycle processes, when software is itself a medical device, or when software is an embedded or integral part of the final medical device [11]. IEC (or BS EN) 60601 refers a family of standards relating to the medical electrical equipment. Part 1 (60601-1) relates to the basic safety and essential performance for all medical electrical equipment. Part of the same family, IEC (or BS EN) 60601-1-6 is an updated collateral standard specifically intended to support the usability of medical electrical equipment. [12] Considering the context of usage, the collateral standard IEC 60601-1-11:2015 (or BS EN BS EN 60601-1-11:2015 + A1: 2021 for those in the UK/EU) considers the basic safety of medical electrical equipment when used in the home environment [13].
European Commission	The European regulatory framework ensures the safety and efficacy of medical devices and facilitates patient access to devices in the European market.	The EU Medical Device Regulation (2017/745) [14] increased focus on usability compared to the former EU Medical Device Directive (93/42/EEC) in recognition of safety issues arising related to usability and an increasing shift to more lay-user managed medical devices [15]. There is an emphasis on specifying the users of a device, and ensuring that the human factors issues that influence use and interactions are fully understood. It aims to ensure the medical device is designed with the end-users and that their cognitive and physical capabilities and limitations are understood and taken into account through the design. N.B. MHRA consultation on the future requirements for UKCA marking following the UK’s exit from the EU is underway.
American National Standards Institute (ANSI)	Promote and facilitate voluntary consensus standards and conformity assessment systems to enhance US global business competitiveness and US quality of life.	ANSI/AAMI HE 75:2009, [16]. Human factors engineering – design of medical devices. Provides detailed guidance on how to perform specific human factors analyses and provides a wealth of design principles

Figure 1. NIHR Devices for Dignity MIC innovation process [22].

Figure 2. Development pathway of SHAPES.

Figure 3. Illustration of the relative size and positioning of SHAPES system in order for the treatment to be administered (stimulator in yellow, electrode array in green, arm sleeve in blue).

Figure 4. Models created for pre-pandemic usability studies of showing different shapes and forms for the stimulator (A). Models incorporating different control options were later produced (B) [40].

Figure 5. (A–C) Illustrative components parts.

Figure 6. Push fit connector with additional grip as used in previous studies.

Figure 7. Electrode array mock-ups slotted into and secured in the model stimulator.

Figure 8. Options for stimulator control.

Table 2. A summary of challenges faced and strategies employed in response.

Challenge	Opportunity/solution
Prototype development
Working from home arrangements affected technical development with reduced access to labs, workshops, fabrication facilities on NHS and University sites Supply and logistical delays: electronic components became unavailable or with lead times of up to a year and other consumables more time-consuming to source. Procurement issues necessitated several unplanned engineering re-designs to accommodate the shortages. Design of non-functional prototypes is informed by the parallel design development of the actual device. Delays in either design or usability sessions impact upon each other.	Made and utilised “paperware” early on to demonstrate key concepts & created standardised video walk-throughs Team members utilised personal fabrication and high-performance computing facilities at home e.g., 3D printers, CAD modelling and simulation, industrial sewing machines and existing material swatches to create prototype functional models and arm-sleeves Team members with access to facilities undertook extra design work that would not usually have been their responsibility.
Preference and iterative usability testing of prototypes with end-users
Face to face user research was not possible due to travel restrictions, social distancing and the vulnerability of stroke survivors and of some team members Online data collection potentially reduced diversity of patients and may have limited inclusion for those without internet access or digital capabilities. Meeting participant needs while meeting and working online Infection control measures to be addressed to enable patients to handle prototypes Online meetings lack the social aspect that many stroke survivors enjoy	Online video platform such as MS Teams and Zoom were employed which enabled participants with internet access to join – who might otherwise might not have wished to attend a physical meeting due to fatigue or the stress of travel With participant consent, offered the opportunity to record and review usability sessions.
Staff resources, collaboration and team work
Team members ill and / or isolating Availability of, and pressure on NHS colleagues as collaborators and participants Necessary prioritisation of other work activities to meet competing organisational or patient needs Team members home working and home schooling Absence of face to face team meetings and team working due to travel restrictions and social distancing measures Uncertainty and changing national and local guidelines	Imbued a collective willingness to overcome adversity (often referred to in the UK as “Dunkirk spirit”). Team members went “the extra mile” to overcome difficulties. Made the most of the online facilities that were available Created bespoke demonstration videos, developed illustrated information sheets and aphasia-friendly versions of information provided.

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