Determined the exact energy level of brain metabolism, which is necessary to restore consciousness

Accurate diagnosis and prognosis for recovering patients after severe brain damage is a difficult clinical task, as some patients maintain a certain level of consciousness, although they do not respond to stimuli. Whether to leave a relative in this state? Is there a chance for recovery?
A team of researchers from Denmark and Belgium
developed a test that answers this question. The test determines the current state of consciousness and allows you to make a fairly accurate prediction of whether the patient will come out of a coma within a year.
The state of consciousness is well diagnosed by conventional positron emission tomography using 18F-fluorodeoxyglucose (PET-FDG). Diagnosis shows the level of glucose metabolism in brain cells.
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"In almost all cases, the energy consumption in the entire brain directly predicts either the current level of consciousness or its subsequent recovery,"
said Ron Coopers (Ron Kupers) from the University of Copenhagen and Yale University, one of the authors of the scientific work. “In short, our work shows that there is a certain minimum energy level for consciousness to recover from brain damage.”
The researchers set the task to develop more reliable diagnostic markers to assess current and future levels of consciousness in addition to standard clinical examinations. They measured and documented the level of cerebral glucose metabolism in 131 patients with complete or partial loss of consciousness.
The study showed that brain metabolism correlates well with the level of consciousness in patients.

Recovery of consciousness after a year in patients with different levels of metabolism: in a vegetative state (UWS) and with minimal consciousness (MCS, EMCS)The energy level of metabolism (42% of normal) was determined, which is critical. Virtually no patients with metabolism below this level regained consciousness during the year after the survey. On the other hand, 94% of patients with metabolism above this energy level showed signs of consciousness during the examination or began to respond to stimuli within a year after receiving the injury.
Discovery means that there is a clear energy level in the brain, below which irreversible changes occur, and the recovery of consciousness becomes impossible. The “magical” level of 42% can be compared to a spark capable of igniting the flame of consciousness in the living brain.
But the most important thing is that the discovery gives hope to patients who are in a vegetative state (UWS on the chart). It turns out that even from such a state, the brain is able to recover if a sufficiently high glucose metabolism is preserved in it.
The scientific work was
published in the journal
Current Biology (doi: 10.1016 / j.cub.2016.04.024,
pdf ).