From December 29 last year, when former Formula One star Michael Schumacher crashed while skiing in France, to June 16 this year, when he finally came out of his medically-induced coma, his life — and his brain — have been in a most confounding state — silent but questioning; calm but uncertain; dead mostly, and yet, still alive. The workings of the brain is one of the most enduring mysteries
What is medically induced coma?
In the case of traumatic head injuries, doctors induce a coma, effectively shutting down brain function. This is done before the body reacts to the injury and shuts off blood flow to damaged sections. To induce a coma, doctors use drugs (propofol or barbiturates such as pentobarbital or thiopental) and then treat high intracranial pressure and slow down the brain’s metabolism so as to minimise swelling caused by the injury. Doctors regularly monitor the patient’s brain activity through a test — Electroencephalography (EEG) — and manually ascertain the amount of the drug’s infusion rate to check the level of consciousness.
The in-between period
In comatose period — a state of profound brain inactivation and unconsciousness — the more active regions (or high-traffic hubs) of the brain enter the dark phase while the quieter ones spring to life. This regional specificity can be understood by the flow of blood, measured using functional magnetic resonance imaging (fMRI) brain scans. Increase in blood flow in a specific region is sign of that region having become more active.
A 2012 study (involving 17 coma patients and 20 healthy ones) tracked 417 brain regions for changes in blood flow. The 40 regions that “lit-up” in healthy patients were “darkened” in coma patients whose peripheral regions (outside of the brain) had more signs of activeness.
Knowing the depth
The Glasgow Coma Scale (GCS) is used to measure the depth of coma, or the level of consciousness, undertaking three aspects — eye opening, verbal response and motor response — consideration.
from 3 to 15 with 3 marking deep coma or death and 15 suggestive of a fully awake person.
Waking up to life
In Kill Bill, Uma Thurman wakes up from a sleep-induced state after four years and all she needs to do before going out on a killing rampage is “wiggle he big toe”. But real life is just that much more complicated. Depending on the severity of the injury, the patient may slip into a persistent vegetative state, minimally conscious state and locked-in syndrome. While arousal (reactive to stimuli) is normal in all three, the difference is in the level of consciousness and motor function.