As doctors re-examine many of the basic assumptions and long-held understandings about concussions, research by Children’s Hospital Boston neurologist Alexander Rotenberg, MD, PhD, is shedding light on what happens on a molecular level during brain injuries. For one of his many research studies, his laboratory is working with the Department of Defense on a project designed to help wounded veterans who have suffered from head trauma. As it turns out, a huge percentage of them go on to develop epilepsy; around half of Vietnam veterans developed seizures a few months after severely injuring their heads.
Working first with rats, Rotenberg and his team of scientists are examining the chemical changes that accompany brain injury. They’re starting with rats that have had severe head injuries (which are easier to measure) and will gradually lower the threshold to milder and milder head injuries, like concussions. So far, Rotenberg is finding that brain cells often become abnormally active after head trauma in a way that’s similar to the over-activity of cells that cause epileptic seizures. “What we need to answer is, ‘What is the biology going on here?” he says.
Taking it to the next level, Rotenberg is also trying to find out whether he can ward off the negative effects of head injuries—including seizures. Using a method that was recently cleared by the FDA to treat patients with major depression called transcranial magnetic stimulation (TMS), he stimulates rats’ brains through short bursts of electrical energy generated through a powerful magnetic field that passes through the rats’ skin and skulls. This painless, noninvasive brain stimulation can have a regulating effect on the neurons of depressed people, and often leads to dramatic recoveries. “There’s a region in the brain that’s a culprit for mood disorders that gets stimulated by TMS,” Rotenberg says. “Somehow this area is susceptible to TMS, so the treatment affects many different brain disorders. But we have no idea how it works yet.”
It’s clear to Rotenberg that any kind of brain stimulation that causes a lasting change in a patient, from lifting them from a depression to stopping their seizures—has to have somehow changed her brain chemistry. In working to solve the puzzle, he’s detecting changes in the brain that are clearly linked to learning and memory. “We might be able to explain why, of all the many possible symptoms someone could have, memory loss and trouble with attention and learning are among the more prevalent ones after someone hurts her head,” he says. “It could be that they’re related to these changes that we’re seeing.”
While Rotenberg is working exploring what kind of chemical changes he’s inducing with electrical brain stimulation in animal experiments, he’s also using TMS to treat a handful of human patients with epilepsy (read a story and watch a video about one of these patients). So far, he’s found that about half of them respond to the treatment. Sometimes, patients’ seizures have stopped completely and, with regular TMS treatment, haven’t returned. While Rotenberg acknowledges that this is very good news for people with epilepsy, he hopes to close the loop on the perplexing circle of head injuries and epilepsy. “Whether this technique can prevent people with head injuries from developing epilepsy remains to be seen,” he says. “I hope so, but I think we’re just scratching the surface.”