Abstract

The subjective experience of consciousness, a cornerstone of human existence, is profoundly disrupted in disorders of consciousness (DOC) arising from severe brain injuries, spanning-states from coma to the minimally conscious state. A significant challenge in clinical practice is the phenomenon of covert consciousness, in which individuals may retain awareness despite the absence of overt behavioral responsiveness. Diagnosis based solely on observable behavior is inherently limited by factors such as co-occurring motor impairments, the fluctuating nature of consciousness, and subjective interpretation, potentially leading to misclassification. To overcome these limitations, neuroscientific methodologies have advanced significantly. To address these limitations, neuroscientific methods have advanced considerably. Functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) provide objective evidence of preserved brain activity and cognitive processing, enabling detection of willful modulation and offering prognostic insight. Electrophysiological techniques—including electroencephalography (EEG), event-related potentials (ERPs), transcranial magnetic stimulation combined with EEG (TMS-EEG), and advanced downstate analysis—further reveal dynamic neural patterns indicative of residual awareness. The detection of covert consciousness has profound ethical, clinical, and societal implications. It necessitates a re-examination of patient rights, end-of-life decision-making, the use of brain-computer interfaces, and societal conceptions of personhood. This evolving understanding mandates a shift towards integrating objective neuroscientific assessments with compassionate, person-centered care, aiming to preserve dignity and navigate the complex ethical landscape of severe brain injury.

Key words: Covert consciousness, functional magnetic resonance imaging, positron emission tomography, electroencephalography, minimally conscious state, unresponsive wakefulness syndrome