Damage to Areas Makes TBI Worse
How come people with traumatic brain injuries have such different neuropsychological outcomes — with some people gradually returning to normal (or near-normal) and others having very significant and permanent problems? For decades neurologist have used a measure of the severity of brain injury called the Glasgow Coma Scale (GCS) to predict outcomes. Although the GCS never explained the causes behind the different outcomes, it did offer roughly accurate predictions about neuropsychological outcome after TBI. The GCS did this based upon a statistical correlation between neuropsychological outcomes and observable factors such the length and depth of the patient’s coma along with the length of his period of post-traumatic amnesia (the amount of time before and after the brain injury he could never remember).
Now (thanks to combining a form of neuroimaging called fMRI with functional connectivity analyses, and graph theory) scientists the University of Iowa and the Washington University of St. Louis have actually found a causal explanation for why brain injury outcomes differ. Their research was just published in the September 15, 2014 Early Edition of the Proceedings of the National Academy of Sciences.
Their research shows that there are 6 “hub” areas in the brain that inter-connect with and integrate other parts of the brain to create the powerful networks responsible for the most important cognitive functions like attention, concept formation, memory, behavioral planning, decision-making, motor movement planning, and speech. When trauma causes focal damage to a brain hub the result will be much more severe than if the damage is diffused and misses all hubs. Think of it the way a major airline runs its business using a hub. If a fire, explosion or electric outage shut down the airline’s hub, the damage to the airline would be much greater than if a number of less important single airports went offline.