High-speed spelling with a noninvasive brain–computer interface

TLDR

BCI technology offers a new communication channel but is limited by low speed. The study aims to develop a high‑speed BCI speller using joint frequency‑phase modulation of steady‑state visual evoked potentials and a user‑specific decoding algorithm, with potential applications for patients with motor disabilities and healthy users. The authors used joint frequency‑phase modulation of single‑trial steady‑state visual evoked potentials and a user‑specific decoding algorithm to synchronously modulate and demodulate EEG signals. The noninvasive speller achieved a multifold increase in information transfer rate, reaching up to 60 characters (≈12 words) per minute.

Abstract

Significance Brain–computer interface (BCI) technology provides a new communication channel. However, current applications have been severely limited by low communication speed. This study reports a noninvasive brain speller that achieved a multifold increase in information transfer rate compared with other existing systems. Based on extremely precise coding of frequency and phase in single-trial steady-state visual evoked potentials, this study developed a new joint frequency-phase modulation method and a user-specific decoding algorithm to implement synchronous modulation and demodulation of electroencephalograms. The resulting speller obtained high spelling rates up to 60 characters (∼12 words) per minute. The proposed methodological framework of high-speed BCI can lead to numerous applications in both patients with motor disabilities and healthy people.