EEG lexicality effect predicts clinical outcome in disorders of consciousness

This study aimed at probing covert language processing in patients with disorders of consciousness. An auditory paradigm contrasting words to pronounceable pseudowords was designed, while recording bedside electroencephalogram and computing the two main correlates of lexicality: N400 and late positive component (LPC). Healthy volunteers and 19 patients, 10 in a minimally conscious state and 9 in a vegetative state (also coined unresponsive wakefulness syndrome), were recorded. N400 was present in all groups, whereas LPC was only present in the healthy volunteers and minimally conscious state groups. At the individual level, an unprecedented detection rate of N400 and LPC was reached, and LPC predicted overt cognitive improvement at 6 months. ANN NEUROL 2023;93:762-767.