Is Information Transfer Rate a Suitable Performance Measure for Self-paced Brain Interface Systems?

Information transfer rate (ITR) is used as the primary metric in the evaluation of many synchronized brain interface (BI) systems. In this paper, the ITR of self-paced BI systems is formulated. It is shown that ITR by itself is NOT a suitable performance measure for self-paced evaluation. Only when there are additional conditions, ITR can be used as a suitable performance measure. Since ITR is achieved through the analysis of the outputs of BI systems, under specific conditions it can be used for comparison between different self-paced BI systems which use similar protocols