# An Agile Approach to Improve the Usability of a Physical Telechabilitation Platform
## 4 Results and Discussion
### Fourth Iteration
This result does not necessarily mean that patients experience the same level of workload since there are several studies on patients' satisfaction with teletreatment that show patients were satisfied with the use of the technology [37], as long as an acceptable level of usability is reached during the operation of the platform. The results show that users in the fourth iteration showed a higher degree of dissatisfaction with their level of performance when carrying out the three proposed tasks. The results showed a variation in the score, passing from a mean of 23.33 (third iteration) to 50.66 (fourth iteration). Conversely, in five of the six remaining dimensions, the scores decreased, which means a lower contribution in the workload. This variation could be due to two factors: (1) The difference of criteria because it was a different group of users; (2) The redesign of the interfaces to reduce the time and effort requirement (third iteration), which affected the performance dimension of NASA-TLX in the fourth iteration. The most convenient solution for the second factor seemed to be using the agile methodology, because of the great diversity of patients using the platform makes it impossible to carry out refinements for each particular case. The results obtained from the heuristic evaluation, the cognitive walkthrough, and the assessments of the NASA-TLX were used as a guide to develop the functional prototype for the ePHoRT platform in this first development cycle. The interfaces' questionnaire and exercises, shown as an example in Figures 12 and 13, are part of the functional prototype. The questionnaire interface allows the assessment of the patient's current situation before performing the exercises. This evaluation is based on three parameters: (1) Pain level; (2) Condition of the skin at the operation site; and (3) State of oedema. This information is sent to the therapists for their evaluation and allows them to decide whether or not a specific set of exercises can be provided to the patient. The exercise interface provides the patient with instructions/recommendations to start the exercise. The instructions can be in video, audio, or text. The patient is authorized to perform the physical exercises following the results of the questionnaire (Figure 12). Figure 11: Distribution of global workload of the six dimensions of NASA-TLX. Applying NASA-TLX provided an additional level of usability testing besides the normal method of observing a user interacting with the platform [38]. For this analysis, the contribution of applying NASA-TLX to a prototype is to predict the minimum workload that a patient will have when using the interfaces and the identification of the interfaces that generate a large workload, thus being able to refine them before the platform is tested on real patients. Usability experts shared their recommendations for the improvement of the interfaces as follows:  
* Increase help tools that describe the operation of the controls of each interface. * Improve the contrast of colors used in the interfaces. * Implement error messages for invalid data entry. * With the text that already appears at the top of each window, add a hypertext menu that informs the user where he/she is located. * The messaging interface should allow attachment of images of the current state of the patient. * There should be some indications whether the username and/or the password are correct or not. * For special users, there should be an alternative way to log in and enter the password. * For visually impaired people, there should be a way either to vocally access the interface or to increase the size of fields and labels on demand. * For future evaluation, it is recommended to use task-based usability inspection. Figure 12: Questionnaire interface improved. Figure 13: Exercise interface improved.