Vegetative state and the outer world

Persistent vegetative state patients (PVS) cases reflect the only circumstance in which an apparent dissociation of both components of consciousness is found. The recent description of the MCS highlights the crucial role of unexpected and well documented recoveries of cognitive functions. Functional neuroimaging has provided new insights for assessing neuropathology and cerebral activity in these patients, providing information on the presence, degree, and location of any residual brain function in PVS or MCS cases. The main finding in PVS is preservation of wakefulness with apparent loss of awareness. Hence, by definition, subjects in PVS with no recognizable behavioral responses to external stimuli, are isolated from the outer world, and they cannot experience pain and suffering. Nonetheless, our results, suggest recognition of the mom’s voice with an emotional content, indicating high-level residual linguistic processing, and brain activation after Zolpidem administration. These results differ with the current concept that by definition, subjects in PVS with no recognizable behavioral responses to external stimuli, are isolated from the outer world, and they cannot experience pain and suffering.These findings launch new medical, ethical and practical implications for the diagnosis and management of PVS and MCS patients.