New functional and imaging-based diagnostic tests that measure communication and signaling between different brain regions may provide valuable information about consciousness in patients unable to communicate.

The new tests, described in an open-access survey article, are functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation (TMS) combined with electroencephalograpy (EEG), and response to neuronal perturbation, measuring, for example, sensory evoked potentials (ERP).

Disorders of consciousness such as coma or a vegetative state caused by severe brain injury are currently poorly understood and their diagnosis has relied mainly on patient responses and measures of brain activity.

Ref.: Mélanie Boly et al., Brain Connectivity in Disorders of Consciousness, Brain Connectivity, 2012, DOI: 10.1089/brain.2011.0049 (open access)