Young football players who suffer a concussion can show signs of reduced blood flow in the brain, even after their symptoms have subsided, a new, preliminary study suggests. Using an advanced form of MRI, researchers found that concussed football players typically showed lower blood flow in the brain eight days after the injury. That was despite the fact that their symptoms had usually gone away by that point. However, the study involved just 18 athletes and it’s too early to know what the findings might mean, experts said. “Does the decreased blood flow indicate a window of cerebral [brain] vulnerability? Nobody has shown that yet,” said Kenneth Podell, co-director of the Methodist Concussion Center in Houston. According to Podell, who was not involved in the study, it’s remarkable that the athletes’ brain blood flow actually declined as their concussion symptoms improved, since that’s counterintuitive on the surface.
The current findings are based on 18 football players, with an average age of 18, who’d suffered a concussion. Each athlete had their symptoms evaluated and underwent brain scans one day after the injury, and again one week later. The researchers used an advanced MRI method that can measure blood flow in the brain. On average, the study found, the athletes’ symptoms had faded by the second evaluation. But their brain blood flow had actually declined. No such change was seen in a comparison group of 19 uninjured players. According to Podell, larger, longer-term studies are needed to know how long the reduced blood flow lasts — and, even more importantly, what it means.
But Podell also cautioned against getting overly alarmed by the concussion risk that comes with sports. “Sports, including contact sports, have a lot of value,” he said. “And keeping kids out of contact sports won’t eliminate their concussion risk.” Falls and car crashes are actually the leading causes of hospitalization for concussion among children and teenagers, according to the CDC.