Table 3 Non-invasive EEG-based brain-computer interfaces in patients with disorders of consciousness – the review of reported studies

Belgium – Lule et al. [14], N = 34

Four training trials and 10–12 questions “yes-no” showed functional communication in patients with locked-in syndrome and other patients with altered states of consciousness

BCI approaches have to be simplified to increase their sensitivity

UK - Kübler and Birbaumer [17], N = 35

Basic communication (yes/no) was restored in locked-in patients, bit not in any of the CLIS patients

BCIs application in CLIS patients still remains an open scientific problem

Italy – Cavinato et al. [20], N = 34

P300 was the only factor contributing to prediction of conscious recovery in patients in post-traumatic VS

Italy - Risetti et al. [24], N = 11

High value of ERPs monitoring in DOC patients aiming at investigation of preserved conscious cognitive function

Belgium, Lugo et al. [25], N = 6

P300 response to vibrotactile stimulation in patients with LIS.

Germany, Steppacher et al. [28], N = 92

Significant relationship between N400 presence and subsequent recovery

Austria, Pokorny et al. [30], N = 22

P300 accuracies were were insufficient for communication purposes in MCS patients

Further investigations are needed

UK, Chennu et al. [32], N = 29

Early, bottom-up P3a and the late, top-down P3b components in response to a pair of word stimuli may be regarded as signs of preserved attention

Further investigations are needed

Canada, Cruse et al. [41]

N20 and N35 somatosensory evoked potential (SSEP) show significant predictive value in patiens in coma

Research on etiology of the predictive power of these SSEP measures is needed