Hybrid asynchronous brain–computer interface for yes/no communication in patients with disorders of consciousness

Abstract

Objective. For patients with disorders of consciousness (DOC), such as vegetative state (VS) and minimally conscious state (MCS), communication is challenging. Currently, the communication methods of DOC patients are limited to behavioral responses. However, patients with DOC cannot provide sufficient behavioral responses due to motor impairments and limited attention. In this study, we proposed a hybrid asynchronous brain–computer interface (BCI) system that provides a new communication channel for patients with DOC. Approach. Seven patients with DOC (3 VS and 4 MCS) and eleven healthy subjects participated in our experiment. Each subject was instructed to focus on the square with the Chinese words ‘Yes’ and ‘No’. Then, the BCI system determined the target square with both P300 and steady-state visual evoked potential (SSVEP) detections. For the healthy group, we tested the performance of the hybrid system and the single-modality BCI system. Main results. All healthy subjects achieved significant accuracy (ranging from 72% to 100%) in both the hybrid system and the single modality system. The hybrid asynchronous BCI system outperformed the P300-only and SSVEP-only systems. Furthermore, we employed the asynchronous approach to dynamically collect the electroencephalography signal. Compared with the synchronous system, there was a 21% reduction in the average required rounds and a reduction of 105 s in the online experiment time. This asynchronous system was applied to detect the ‘yes/no’ communication function of seven patients with DOC, and the results showed that three of the patients (3 MCS) not only showed significant accuracies (67 ± 3%) in the online experiment, and their Coma Recovery Scale-Revised scores were also improved compared with the scores before the experiment. This result demonstrated that 3 of 7 patients were able to communicate using our hybrid asynchronous BCI system. Significance. This hybrid asynchronous BCI system can be used as a useful auxiliary bedside tool for simple communication with DOC patients.

EEG-based Brain-Computer Interfaces for people with Disorders of Consciousness: Features and applications. A systematic review

“…Five of the 11 patients enrolled (2 VS/UWS, 2 MCS, 1 EMCS; 45.5%) reached a significant classification accuracy both in a task of number recognition and number comparison and 3 out of 5 patients (1 VS/UWS, 1 MCS, 1 EMCS) reached a significant classification accuracy also in a mental calculation task. Finally, Huang et al ( 2021b ) implemented a hybrid asynchronous BCI as a communication channel and 3 MCS patients out of 7 DoC patients tested (42.9%) gained accuracies higher than the chance level.…”

Pain assessment during physiotherapy and noxious stimuli in patients with disorders of consciousness: A preliminary study

“…According to recent research, these patients could be diagnosed with MCS star with covert consciousness (diagnosed as UWS based on CRS-R assessment but with minimal preservation of brain metabolism) ( Thibaut et al, 2021 ) or cognitive motor dissociation (CMD, patients show no detectable command-following behaviors, but there is clear evidence of command-following brain activity) ( Egbebike et al, 2022 ). One research study found that three out of seven DOC patients could communicate using the asynchronous brain-computer interface (BCI), suggesting that BCI can be a helpful tool for bedside communication with DOC patients ( Huang et al, 2021 ). In addition, another study found that 83.33% of patients with CMD diagnosed with BCI were able to regain consciousness, indicating that clinicians can recognize the awareness of BCI-based clinical diagnosis in DOC patients ( Pan et al, 2020 ).…”

Brain–Computer Interfaces for Awareness Detection, Auxiliary Diagnosis, Prognosis, and Rehabilitation in Patients with Disorders of Consciousness

“…Several representative works on BCI-based awareness detection in patients with DoC are shown in Table 1 . 17 18 19 20 21 22 23 24 25 26…”

“…1. [17][18][19][20][21][22][23][24][25][26] As the vision of most patients with DoC is commonly limited, researchers naturally considered using an auditory paradigm to detect awareness. Lulé et al first used an auditory P300 paradigm to detect awareness in patients with DoC.…”