Functional Neuroimaging Approaches to the Changing Borders of Consciousness

The bedside diagnosis of vegetative and minimally conscious patients is extremely challenging, and prediction of individual
long-term outcome remains difficult. State-of the art neuroimaging methods could help disentangle complex cases and offer new prognostic
criteria. These methods can be divided into to three categories: First, new anatomical MRI neuroimaging methods, like diffusion
tensor imaging (DTI) or spectroscopy, and passive functional imaging methods (looking at the brain’s activation induced by external
stimuli), could provide new diagnostic and prognostic markers. Second, neuroimaging methods based on active collaboration from the
patient could help to detect clinically unnoticed signs of consciousness. Third, developments in brain-computer interfaces based on EEG,
functional MRI, or EMG offer communication possibilities in brain-damaged patients who can neither verbally nor nonverbally express
their thoughts or wishes. These new approaches raise important issues not only from a clinical and ethical perspective (i.e., patients’
diagnosis, prognosis and management) but also from a neuroscientific standpoint, as they enrich our current understanding of the emergence
and function of the conscious human mind.