I have never read anything that says the concussed brain processes glucose differently. I have seen that for some people, they are more sensitive to food energy levels. The brain only gets energy from glucose or ketones when glucose is not available. If the orange juice solves the jitters, it shows that your brain is processing glucose.

There may be a quickness for the concussed brain to start an adrenaline reaction. Many experience a heightened adrenaline reaction after a concussion. It is the adrenaline that causes the jitters. I can get the jitters from stress as stress can cause the adrenaline reaction.

Either way, it is not good for you to stress your brain by not eating unless you are doing a planned fast and are in a safe period, no driving, no operating machinery, no making important decisions.