Consciousness revealed: new insights into the vegetative and minimally conscious states

PURPOSE OF REVIEW: In recent years, the results of neuroimaging studies have fundamentally changed the way we think about the vegetative and minimally conscious states.

RECENT FINDINGS: Functional MRI studies have demonstrated that some high-level cognitive functions, such as language comprehension and target detection, are preserved in a subset of patients with disorders of consciousness. Similar methods have even allowed a patient who was assumed to be in a vegetative state to communicate. PET has provided insights into similarities and differences in the ways in which pain is processed by this patient group, whereas electrophysiological methods have revealed further evidence of awareness as well as learning.

SUMMARY: The prognostic and diagnostic information provided by these new approaches clearly argues for their future use alongside conventional assessment techniques. By demonstrating that a behaviourally unresponsive patient could communicate by means of his/her thoughts using functional MRI, these new techniques open up a new direction of research into the development of more sophisticated communication devices that may be used more generally by these patients. In our opinion, such devices, employing electroencephalograph among other techniques, may soon allow for patients who retain sufficient cognitive abilities to communicate, to do so outside of an MRI scanner.