Functional connectivity between two regions of the brain may help predict which comatose patients will regain consciousness, according to research published in Neurology.

Previous research has indicated that resting-state functional connectivity with the posteromedial cortex is correlated with the degree of clinical consciousness impairment in healthy controls, those with locked-in syndrome, and those who are in a minimally-conscious or vegetative state. In this study, Stein Silva, MD, PhD, of the French national research institute, INSERM U825, and colleagues explored whether the breakdown of neuronal connectivity with the precuneus and posterior cingulated cortex (PCC) affected prognosis of comatose patients.

Twenty-seven comatose patients with severe brain injury (14 traumatic, 13 anoxic cases) and 14 age-matched health controls underwent functional MRI to assess resting-state connectivity. In comatose patients, the MRI was conducted after withdrawal of sedation (4 +/- 2 days). Patient outcomes were assessed at 3 months using the Coma Recovery Scale-Revised (CRS-R).

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At follow-up, 4 comatose patients had regained consciousness, while the others remained in a minimally-conscious or vegetative state. Patients who were comatose showed significant disruptions of functional connectivity in brain areas spontaneously synchronized with the PCC. Functional connectivity strength between the PCC and media prefrontal cortex (mPFC) was significantly different in comatose patients who went on to recover compared to those with an unfavorable outcome at 3-month follow-up (Kruskal-Wallis test, P=0.001; linear regression between CRS-R and PCC-mPFC activity coupling at rest, Spearman r, 5 0.93, P=0.003). The coordination of activity between the PCC and mPFC was the same for healthy controls and patients who regained consciousness, suggesting that spared functional connectivity may help predict patient outcome.  

“We need to do more studies with larger numbers of patients to substantiate these results, but the findings are promising,” Dr. Silva said. “We could be able to predict better who is more likely to recover from a coma and eventually develop innovative networks-based personalized treatments for people with brain injuries.”


  1. Silva S, de Pasquale F, Vuillaume C, et al. Disruption of posteromedial large-scale neural communication predicts recovery from coma. Neurology. 2015; doi: 10.1212/WNL.0000000000002196.