Summary of findings for version 1.0 of the GUI and usability

Version 1.0 of the GUI proved to be a useful starting point for guiding users through the setup process for the UL FES Rehab Tool. However, the findings from phase two of the usability evaluation highlighted a number of areas that warranted design revisions. As a result of the user walk-throughs and feedback, 23 design revisions were made to the GUI. All 10 priority 3 problems, 11 out of 12 priority 2 problems and 2 out of 12 priority 1 problems were addressed. Only a priority 2 problem that related to how to deal with ramp times was omitted, as the design team wanted to determine how this worked in practice once stimulation was applied. The 12 priority 1 problems were deemed to have a low impact on users and did not affect the functionality of the software. Hence, only 2 of these problems were addressed. The most significant revisions have been summarised below (referred to as P# plus number, to correspond with the list in Appendix 8), along with direct quotes from users in order to illustrate the point.

Ai) FES and state machine functionality that generalized across the GUI

One of the main design changes related to the functionality of the GUI was the inclusion of the option to use a keyboard button press to adjust stimulation settings as an alternative to using the mouse (P#2 & 3, Appendix 8). During the usability ‘walkthrough’ two users [Users 1 & 2] reported that the mouse was difficult to use for setting stimulation levels in stage two, whilst a further user reported that adjusting stimulation levels in stage three was ...“Definitely not a 1 person job!” [User 5, post- test questionnaire]. User feedback suggested that that an alternative method would make it easier to interact with the GUI whilst handling a patients’ limb “Adjusting stimulation levels not suitable using mouse - would prefer a dial e.g. hifi volume dial.” [User 5, post-test questionnaire]. Often patients require assistance from the therapist in order to move their hemiplegic arm, particularly when moving against gravity. The option of using the keyboard to adjust stimulation levels meant that the therapist could concentrate on observing and interacting with the patient, rather than needing to accurately position the mouse cursor on the stimulation slider bar. Similarly, keyboard input for moving between transitions and stopping stimulation was implemented.

102 Four users (‘walkthrough data’) felt that the slider that adjusted stimulation responded too slowly in stages two and three (P#1). More importantly, there was no maximum stimulation level imposed on the system for stage two. Due to the lag in stimulation adjustment displayed by the GUI, hypothetically this could have allowed the user to inadvertently adjust the stimulation to an uncomfortable level without realising. As a result, a maximum stimulation level was imposed in stage two. In addition, a safety block was added as a final safety feature. The safety block was the final gateway for stimulation before it passed to the patient. Introducing a safety block at this stage meant that it was not possible for stimulation levels to exceed a critical comfort threshold, whether this was due to a software ‘bug’ or user error (Sun, 2014). Another example of a comfort/safety-related problem with v1.0 that was raised by the users was the absence of a timeout function. During the usability ‘walkthrough’ in both stages two and three, all six users left stimulation on without realising it. In addition [User 5] in the post-test questionnaire commented……“I did feel I was stimulating the patient (hypothetically) rather a lot and this could be uncomfortable.” A timeout function could, in the eventuality that stimulation was left on for too long sound a buzzer to alert users that stimulation was still on (P#4 & 5).

Although software ‘bugs’ did not appear to be critical to the safety of the device, they were very irritating to the user and twice during the usability ‘walkthrough’ result in the system ‘crashing’. Four software ‘bugs’ were identified from the user ‘walkthroughs’ and subsequently resolved (P#34). In order to ensure that any remaining software ‘bugs’ could not affect the level of stimulation provided to patients, a safety block was implemented as an additional safety mechanism (Sun, 2014).

Opinion on the length of time it took to setup the device was divided. However, none of the users rated the setup time better than acceptable. One novice user (User 5) rated the setup as excessively long, one expert and one novice user (User 2 & User 4) rated the setup time as quite lengthy, whilst the remainder, two expert and one novice user (Users 1, 3 & 6), rated it as acceptable. [User 6] stated setup time should be “10 mins max to setup and adjust stimulation. 20 mins for a new patient.”

103 Aii) Ergonomics

Changes that fell into category Aii) were predominantly design revision that would make navigation around the GUI more intuitive e.g. renaming of buttons (P#10), inclusion of a save button (P#6), and avoiding errors in navigation (P#8) e.g. error message when users attempt to move to the next stage of the setup process without completing the existing stage. Where changes required little effort to amend the design, even if listed as a low priority, they were implemented. An example of a simple change was listing the muscles in alphabetical order to make finding suitable muscles easier and quicker (P#12).