An open interface system for non-invasive brain-to-brain free communication between naive human participants

Abstract

Keywordsamyotrophic lateral sclerosis, anarthria, BCI speller, brain-machine interface, computer keyboards, electroencephalography (EEG), filter-bank canonical correlation analysis (CCA), hyperscanning, open science, neuroimaging, quadriplegia, steady-state visual evoked potential (SSVEP), virtual reality (VR), visual selective attention AbstractFree and open communication is fundamental to modern life. Brain-computer interfaces (BCIs), which translate measurements of the user's brain activity into computer commands, present emerging forms of hands-free communication. BCI communication systems have long been used in clinical settings for patients with paralysis and other motor disorders, and yet have not been implemented for free communication between healthy, BCI-naïve users.Here, in two studies, we developed and validated a high-performance non-invasive BCI communication system, and examined its feasibility for communication during free word association and unprompted free conversation. Our system, focusing on usability for free communication, produced information transfer rates sufficient and practical for free association and brain-to-brain conversation (~5.7 words/minute). Our findings suggest that performance appraisals for BCI systems should incorporate the free communication scenarios for which they are ultimately intended. To facilitate free and open communication in healthy users and patients, we have made our source code and data open access. OverviewFree and open communication is fundamental to modern life, scientific enterprise and democratic discourse. The rising prevalence of technologies such as virtual/augmented reality [1][2][3][4] and artificial intelligence [5; 6] has created new opportunities for hands-free communication and control. Brain-computer interfaces (BCI), which translate measurements of the user's brain activity into computer commands to control external devices [7][8][9][10][11] , present emerging forms of hands-free communication. BCI spellers are virtual keyboards that decode brain activity patterns allowing users to select characters in sequence to spell words and, ultimately, freely communicate [12] . BCI keyboards mimic manual keyboards, which extend the user by allowing them to physically manifest their real-time thoughts, interface with the internet and communicate remotely. BCI communication systems, including spellers, have long been used in clinical settings to facilitate communication in cases of quadriplegia, anarthria and amyotrophic lateral sclerosis [13][14][15] . These systems are often developed using electroencephalography (EEG), which allows for portable, flexible and affordable devices [16] . BCI has the potential to revolutionise communication, and yet its potential for creating free communication in healthy users is largely unexplored [17] . Here we introduce a new and efficient non-invasive system, using sparse-electrode electroencephalography (EEG), that allows free communication between individuals based on real-time brain activity decoding.Remarkable pro...