Identifying Electrophysiological Components of Covert Awareness in Patients with Disorders of Consciousness

Naturalistic stimuli evoke synchronous patterns of neural activity between individuals in sensory and higher cognitive, “executive” networks of the brain. fMRI paradigms developed to measure this inter-subject synchronization have been extended to test for executive processing in behaviourally non-responsive patients as a neural marker of awareness. This thesis adapted one such paradigm for use in EEG, a low-cost, portable neuroimaging technique that can be administered at a patient’s bedside. Healthy participants listened to a suspenseful auditory narrative during EEG recording. Significant inter-subject synchronization was found throughout the audio but was significantly reduced during a scrambled control condition. This paradigm was then used to evaluate executive processing in a cohort of patients. One locked-in patient and one patient in a vegetative state were significantly synchronized to healthy controls during the audio. EEG is a suitable tool to detect executive processing, a proxy measure of awareness, in patients who are behaviourally non-responsive