Designing Digital Therapeutics: How the User Experience Can Impact Real-World Adoption?

The method is quite similar, but what makes it different are the users themselves. Our users are patients. Some might have dexterity issues that make it difficult to hold and manipulate a smartphone. Others might have treatment-related side effects such as fatigue, memory or concentration issues, pain or nausea. Because a patient’s condition will impact their use of the solution, we have to use these “characteristics” as an input for the design of the solution.

Another difference relates to the formalization of the activities we conduct with the end users to address regulatory requirements. In fact, the human factors activities conducted all along the design and development of the solution must be tracked and presented to health authorities before the device is commercialized.

There are three main ways to collect information on users’ needs:

• Conducting interviews or focus groups with the intended users will give you a deep understanding of how a disease impact their life, as well as the difficulties they might experience or have experienced. You begin to understand what really matters for them – and what solutions they might have found themselves in the face of these difficulties.
• Patient experts and Key Opinion Leaders also bring valuable feedback. Both are interested in sharing their experience to help research, science and any other initiative that aims to improve the patient’s quality of life.
• Finally, a literature analysis can help identify unmet needs and learn about challenges encountered by other researchers or patients who have designed or used similar solutions.

The IEC 62366 medical devices standard describes two main evaluation activities: formative studies and summative studies (also called Human Factors Validation Testing). Both play an important role in ensuring that a DTx product is both useful and usable.

A formative study happens at key milestones throughout the software development lifecycle. The solution doesn’t need to be finalized for a study to take place; it can be conducted on wireframes, screen mock-ups or prototypes. It enables the manufacturer to identify the strengths and weaknesses of the current solution and to identify design changes that would enhance its overall usability.

Formative studies can rely on the expertise of human factors specialists who conduct expert reviews of the device’s user interface, based on ergonomics criteria. The manufacturer may also decide to conduct a user test where a small panel of intended users are invited to use the device during individual test sessions and provide their feedback. In particular, the manufacturer will want to know any difficulties they experience when using the device.

The summative study is a key validation step in the development of a digital therapeutic. It aims to provide clear evidence of the effectiveness and safe use of the solution. It takes place once the product is finalized and before a file is submitted for regulatory clearance.

The summative study is conducted like a user test. There should be at least 15 participants per intended user group, such as 15 patients or 15 healthcare professionals in our case. While the formative studies can be conducted on any features of the device, the summative study must focus on critical tasks that could lead to a serious harm for the user. These tasks are defined according to the results of the risk analysis. The manufacturer delegates the organization of the summative study to a human factors company specializing in the evaluation of medical devices. Depending on the finding, the manufacturer might need to make design changes and then conduct a supplemental validation testing to assess the efficiency of these design changes.

If you want your device to be used, you must ensure two things: First, it must be useful, meaning that it answers users’ needs. Secondly, you have to make sure that it is usable, meaning that it is easy to use. If you create a device that is useful but that nobody knows how to use, well, nobody will use it. If you create a device that is super easy to use but does not meet users’ needs, again, nobody will use it. User satisfaction is key, and you really have to pay attention to the user experience!