MINNEAPOLIS - It has been exactly one week since a deadly explosion destroyed part of Minnehaha Academy in Minneapolis.

Two people were killed, and several hurt.

Those injuries were visible. But others are still being monitored for possible injuries that can't be seen – concussions.

Staff and athletes experienced something that could be compared to what those in the military have experienced at war.

Doctor Uzma Samalani, a neurosurgeon at the VA hospital, has studied blasts like what happened at Minnehaha Academy and the affects those blasts have on the brain.

“So what we know, looking at the military experience, is that being in the vicinity of a blast has the potential to cause changes in the brain," she said. "It’s thought that the shock waves can travel through the skull, through the eyes, the ears, potentially affect the blood pressure in the body and cause changes in pulse pressure going to the brain."

She said many people who have a blast injury don’t even know it.

“There are people who had a blast injury and were not knocked over and not knocked unconscious," she said. "They sometimes feel the blast hit them and they feel the exposure to the shock wave but they don’t necessarily realize it’s caused problems to their brain. They may notice things later. The thing about blast and that’s complex, it may not cause immediate symptoms."

If a person doesn't feel immediate symptoms like headache, nausea, vomiting and vision problems, that doesn’t mean they shouldn’t get checked out.

“I think the most important thing for someone who’s been exposed to a blast is to take it seriously and to get checked because the danger is in not knowing," Samalani said. "As long as you know, you can understand what’s going on and then you can treat it."

Samalani also said a majority of people with concussions, whether due to an impact to the head or blast exposure, do recover fully.

But that recovery involves receiving the proper treatment from a specialist.

“It’s a small percentage, between 3 and 10 percent that don’t recover fully," Samalani said. "Some component of that is genetics, because we know certain genes help you recover; and some component is environmental, we know being in a resilient family helps, socioeconomic status and education help people with recovery, so there are factors that play a role in recovery."