The effect of perceived auditory feedback on speech Brain-Computer Interface decoding performance

Objective: Brain-Computer Interfaces (BCI) provide alternative means of communication for individuals with severe motor impairment. Implantable speech BCIs have shown great potential, particularly in individuals who could still produce some speech-related movements and/or sounds. As perception of auditory feedback is important for correct speech sound production in able-bodied people, it is conceivable that a complete absence of such feedback in individuals who lost all ability to produce audible speech affects BCI performance. The current study therefore set out to investigate to what extent perception of auditory feedback of self-produced speech contributes to speech decoding performance. Methods: In three able-bodied participants, patterns of 65–95 Hz power over sensorimotor cortex were compared between normal speech and speech in which auditory feedback was masked by noise. In addition, decoding accuracy was compared between feedback situations. Results & Conclusions: We found subtle differences in brain activity patterns associated with speech production between situations in which participants could versus could not perceive their produced speech. Importantly, absence of such auditory feedback led to lower speech decoding performance in all participants. Significance: These results underline the need to validate speech BCI efficacy with fully paralyzed individuals, as perceived feedback can influence the attainable speech decoding accuracy.