Chronic physical impairment of the hemiplegic upper limb (UL) is seen in an estimated 50-70% of stroke patients, who place a high priority on regaining upper limb function. Current therapy is insufficiently intensive, often not task-oriented and hence poorly aligned with the evidence base.
Functional electrical stimulation (FES) has the potential to not only increase the intensity of task-focused therapy, but also provide certain unique features, notably direct excitation of lower motor neurons. However, current FES systems are limited in their functionality and/or difficult to use. Systems are also poorly aligned to therapists’ ways of working and uptake remains limited.
To address these problems, a novel FES technology (UL FES Rehab Tool) has been developed. The control system design is reported in Sun, (2014). The aims of my thesis were to:
- 1) design a Graphical User Interface (GUI) that would enable therapists to quickly and easily set up an individually tailored library of FES tasks for each patient;
- 2) evaluate the usability and functionality of the UL FES Rehab Tool (software and hardware) in both laboratory (lab) and clinical settings.
An iterative, mixed methods, five-phase usability engineering approach was used to design and evaluate the UL FES Rehab Tool. Phases one to three incorporated identification of therapists’ requirements, a user ‘assisted walkthrough’ of the software with expert and novice FES users and ‘rapid prototyping’ of the full system, using healthy participants. Further usability testing of the software & hardware was conducted in phase four with 1 physiotherapist and 6 patients, (total of 24 visits), in the chronic stage post-stroke. The work demonstrated in detail, for the first time, the impact of therapist involvement in the design of novel rehabilitation technology.
To address therapists’ focus on setup time, using the phase four data set, a novel model to predict setup time was devised. This model was able to explain 51% of the variance in setup time based on two parameters, task complexity and patient impairment. Finally, in phase five, a summative usability evaluation of the final prototype was carried out in 2 sub-acute stroke units. Four therapists and 1 rehabilitation assistant used the UL FES Rehab Tool with 6 patients in the acute stage post-stroke. The UL FES Rehab Tool enabled all therapists and one therapy assistant to effectively deliver FES assisted upper limb task-oriented therapy to a range of stroke patients (Fugl-Meyer scores 8–65). The usability methods effectively captured objective and subjective feedback from therapists and patients. However the previous setup time model was unable to predict setup time, suggesting other factors were important in a clinical setting.
Although participant numbers were low, the results suggested therapists’ predisposition to using technology and post-training confidence in using the technology may influence their willingness to engage with novel rehabilitation technologies.
This study is the first to describe in detail the impact of a usability engineering approach on the design of a complex upper limb rehabilitation technology from early stage design to clinical evaluation. These methods can be generalised to other studies seeking to explore the usability of new forms of rehabilitation technologies.