The University of British Columbia

The low-frequency asynchronous switch design (LF-ASD) was introduced as a direct brain computer interface (BCI) technology for asynchronous control applications. The LF-ASD has the advantage that it is operational at any time and not only at specific defined periods. It is activated only when a user intends control, otherwise it maintains an inactive state output. The intended control results from a certain movement attempt such as finger flexion. This paper presents the evaluation of a modified LF-ASD design with data collected from individuals with high-level spinal cord injuries and able-bodied subjects. The modifications are related to incorporating into the system more knowledge about the movement attempt. Specifically, the past values of the features extracted from the EEG signal related to the movement attempts are used. The error characteristics of this new asynchronous brain switch design are significantly better than the previous LF-ASD design, with true positive rate increases of approximately 8.5% for false positive rates in the range of 1-2%