arxiv.orgpaper

A Common Measure of Communication for Speech Brain-Computer Interfaces

This arXiv paper introduces open-vocabulary mutual information (OVMI), an information-theoretic metric for evaluating speech brain-computer interfaces (BCIs) that decode neural activity into language. OVMI addresses the field's lack of a common progress measure by scoring decoders against a reference distribution over words a user may want to communicate, rather than only over a system's supported vocabulary, exposing how standard metrics like accuracy and WER can overstate real communicative capability. The authors show that selecting a vocabulary to maximize OVMI yields up to 16.3% relative accuracy improvement across three speech domains.