Article

For the rehabilitation process, the treatment of patients surviving brain injury
in a vegetative state is still a serious challenge. The aim of this study was to
investigate patients exhibiting severely disturbed consciousness using functional
magnetic resonance imaging. Five cases of posttraumatic vegetative state and one
with minimal consciousness close to the vegetative state were studied clinically,
electrophysiologically, and by means of functional magnetic resonance imaging.
Visual, sensory, and acoustic paradigms were used for stimulation. In three
patients examined less than 2 months after trauma, a consistent decrease in blood
oxygen level dependent (BOLD) signal ('negative activation') was observed for
visual stimulation; one case even showed a decrease in BOLD activation for all
three activation paradigms. In the remaining three cases examined more than 6
months after trauma, visual stimulation yielded positive BOLD contrast or no
activation. In all cases, sensory stimulation was followed by a decrease in BOLD
signal or no activation, whereas auditory stimulation failed to elicit any
activation with the exception of one case. Functional magnetic resonance imaging
in the vegetative state indicates retained yet abnormal brain function; this
abnormality can be attributed to the impairment of cerebral vascular
autoregulation or an increase in the energy consumption of activated neocortex in
severe traumatic brain injury.

Langue : ANGLAIS