Abstract. A Brain Computer Interface (BCI) is a control and/or communication system in which the user’s commands and messages do not depend on muscular control. If BCIs were to be considered and evaluated as assistive technology facilitating daily activities, they could avoid dissatisfaction and prevent abandonment. Approaches such as “User-centered design”, “User interfaces for all” and the most recent “Integrated model of usability” already highlight the importance of a complete and full evaluation of the interaction. The tradition of Human Computer Interaction (HCI) has already given us most of the tools we need to analyse and evaluate technology. In a series of studies, we assessed the usability of two BCI prototypes by measuring interaction with the systems in context, considering the performance, cognitive workload and satisfaction of non-disabled users in order to better understand how the interface affects these parameters. We tested two keyboard-controlled Java BCI prototypes based on the Thought Translation Device and the P300 Speller (P3S). In the first evaluation, we tested the learnability of BCIs on 6 healthy users through the Thinking Aloud technique, which showed that while all users easily learned how the system worked with Language Support Program (LSP), they failed with P3S. We then tested BCI efficiency on 30 participants (15 with LSP and 15 with P3S) through the Copy Spelling Task (CST) and administered the System Usability Scale (SUS) to measure usability and the Survey of Technology Use (SOTU) scale of the Matching Person and Technology (MPT) to measure predisposition to the use of technology. With the CST, we found that P3S users were more accurate in selecting and recognising letters on the screen. Both SUS and SOTU did not show any significant effects. After modifying our testing paradigm, we tested again using 61 participants with different computer skills, and administered usability and cognitive workload questionnaires. The results showed significant differences in the number of performed errors as well as in user satisfaction and the cognitive workload invested in the task. We found that the Thought Translation Device was more error-resistant, less stressful and more satisfactory for the users compared to the P3S.
Usability of Brain Computer Interfaces
FEDERICI, Stefano;
2011
Abstract
Abstract. A Brain Computer Interface (BCI) is a control and/or communication system in which the user’s commands and messages do not depend on muscular control. If BCIs were to be considered and evaluated as assistive technology facilitating daily activities, they could avoid dissatisfaction and prevent abandonment. Approaches such as “User-centered design”, “User interfaces for all” and the most recent “Integrated model of usability” already highlight the importance of a complete and full evaluation of the interaction. The tradition of Human Computer Interaction (HCI) has already given us most of the tools we need to analyse and evaluate technology. In a series of studies, we assessed the usability of two BCI prototypes by measuring interaction with the systems in context, considering the performance, cognitive workload and satisfaction of non-disabled users in order to better understand how the interface affects these parameters. We tested two keyboard-controlled Java BCI prototypes based on the Thought Translation Device and the P300 Speller (P3S). In the first evaluation, we tested the learnability of BCIs on 6 healthy users through the Thinking Aloud technique, which showed that while all users easily learned how the system worked with Language Support Program (LSP), they failed with P3S. We then tested BCI efficiency on 30 participants (15 with LSP and 15 with P3S) through the Copy Spelling Task (CST) and administered the System Usability Scale (SUS) to measure usability and the Survey of Technology Use (SOTU) scale of the Matching Person and Technology (MPT) to measure predisposition to the use of technology. With the CST, we found that P3S users were more accurate in selecting and recognising letters on the screen. Both SUS and SOTU did not show any significant effects. After modifying our testing paradigm, we tested again using 61 participants with different computer skills, and administered usability and cognitive workload questionnaires. The results showed significant differences in the number of performed errors as well as in user satisfaction and the cognitive workload invested in the task. We found that the Thought Translation Device was more error-resistant, less stressful and more satisfactory for the users compared to the P3S.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
