Brain computer interfaces (BCIs) translate basic mental commands into computer-mediated actions. BCIs allow the user to bypass the peripheral motor system and to interact with the world directly via brain activity. These systems are being developed to aid users with motor deficits stemming from neurodegenerative disease, injury, or even environmental restrictions which make movement difficult or impossible. One popular class of EEG-driven BCI systems is based on imagined movement. In these systems the user interacts with a computer through motor imagery such as the imagination of hand vs. tongue movement. But the ability of users to control such a BCI is very variable, and all the factors involved are not fully understood. For example, EEG signals can change drastically from offline training to online use. Unfortunately, drift in EEG can lead to loss of control of the BCI, which leads to user frustration and further drift of EEG signals from their training baselines.
The PI's goal in this project is to create a more robust BCI system by specifically addressing loss of control and system drift. Her hypothesis is that explicitly training on a signal that incorporates a user's satisfaction and, more importantly, dissatisfaction with the current performance may result in a more natural interface, and thereby lead to a reduction in loss of control and improved system usability and performance. The research will be carried out in three stages. First, active and passive EEG signals of dissatisfaction and satisfaction will be analyzed in a simulated online setting. Next, a real-time online system that recognizes dissatisfaction vs. satisfaction to control 1-D cursor movement will be constructed and system performance compared to that of a standard left/right motor imagery system. Finally, the best working parts of the dissatisfaction/satisfaction system will be integrated with the more standard left/right system, to create a better hybrid system. The (dis)satisfaction signals will be based on actively controlled motor imagery signals, interpreted emotion, and detection of error-like signals.
Broader Impacts: This project has the potential to vastly improve the robustness of EEG-based BCI systems, by responding to natural signals of satisfaction and dissatisfaction, by being resistant to drift, and by naturally taking advantage of frustration which is a common cause of loss of control. By training the BCI to recognize frustration the PI expects to turn this typically negative trait into a positive. The project will support and train an under-represented minority graduate student and a post-doc in this important interdisciplinary area, and it will create projects for under-represented REU participants as well as for high school students through the PI's partnerships with the NSF Temporal Dynamics of Learning Center (TDLC, where she is a member of the faculty governing and admissions committee for the REU program) and the Preuss School (a charter school for low income students with no college educated parent). All software written for EEG signal processing and analysis, as well as data from the experiments, will be made available as add-ons to EEGLAB which is distributed by co-PI Makeig.
