question: How functional connectivity of the default mode network changes in patients with disorders of consciousness?
answer: Functional connectivity in the default mode network (DMN) is reduced in patients with different disorders of consciousness, and correlates with the level of consciousness. 
  Specifically, functional connectivity in the default mode network was shown to be absent in brain death patients, extremely low in vegetative state patients and slightly decreased in minimally conscious state patients when compared to healthy subjects. Therefore, functional connectivity in the default mode network was suggested to be valuable in differentiating patients with different disorders of consciousness. Clinically, functional connectivity in the default mode network was also shown to be an indicator of the extent of cortical disruption and predict reversible impairments in consciousness.