As the Green Bay Packers and the Pittsburgh Steelers prepare to take the field for Super Bowl XLV, many football fans are wondering if there are any lingering effects from multiple concussions that sidelined Green Bay's quarterback, Aaron Rodgers this season.
It's no secret Rodgers has had a rough season when it comes to taking hits. His first concussion came on October 10 in a game against the Washington Redskins, but he returned to the field the following week.
Two months later, Rodgers took another hit from Detroit Lions linebacker, Landon Johnson, that left him seemingly disoriented on the field. It was later announced that Rodgers had suffered his second concussion of the season, and he was sidelined for the next game while he recovered.
Dr. Mitchel Berger, a member the National Football League's Head, Neck and Spine Medical Committee and chairman of the department of neurological surgery at the University of California, San Francisco School of Medicine said NFL players like Rodgers who suffer concussions must go through rigorous testing before returning to the field.
"Once they are accurately diagnosed with a concussion, there's a physical exam and a neuropsychological evaluation, which consist of a computerized test, and assessment by an independent physician - or a secondary independent advisor to the team physician," Berger, who has not treated Rodgers, said. "Once they clear that, then they are deemed ready and able to play without any restrictions."
Rodgers was drilled again in late January during the NFC Championship game, when Chicago Bears' defensive end, Julius Peppers, dealt him a brutal blow to the head that pushed up Rodgers' helmet and drew blood.
Peppers was later fined $10,000 by the NFL for the illegal hit that violated the league's strict new rules about helmet-to-helmet contact. And while many sports bloggers and reporters speculated about a third concussion for the star quarterback, Rodgers dismissed the rumors and credited a newly designed helmet with protecting him.
But the fact that Rodgers experienced multiple concussions this season doesn't necessarily mean he has a greater chance of suffering another one if he's hit again on Sunday.
"I think his risk is not that significant or greater than if he hadn't had any this season," Berger said. "Having had an event a month or six weeks ago, he's essentially back to baseline, otherwise he wouldn't have been cleared to play. Once we clear a player to go back, based on the guidelines, that player is clear to go and really doesn't have any increased risk."
Diagnosing concussions can be difficult, but there are several symptoms doctors look for on the sidelines to determine the severity of a head injury, and whether a player can return to the field.
"Well there are actually a number of different events that take place, for example memory - loss of memory or retrograde memory - they can't remember the play or practice the day before; there can be confusion, hypersensitivity to sound and light, dizziness and vertigo," said Berger. "Those are generally the subjective findings, and then objectively, when a player is evaluated, you can see difficulty with balance or you can see the eyes flutter a bit when they look to the left, right, up or down."
Headaches are another symptom that is checked for before and after the event, and if the player is not able to sleep at night, that's a sign that they're still having lingering effects, Berger added.
But a new test developed by researchers at the University of Pennsylvania School of Medicine could make it easier for doctors to diagnose head trauma on the sidelines in as little as one minute.
It's called the King-Devick test and involves athletes reading single digit numbers shown on index-sized cards. The test is so effective because it's able to capture impairments of eye movement, attention, language and other symptoms of impaired brain function, according to the researchers.
Sideline injury assessments are commonplace in the NFL - but only after falling under intense scrutiny by Congress and the medical community, has the league started to put more emphasis on the reporting and treatment of concussions, and has even committed to support research of the long-term effects.
"The likelihood of having a concussion has increased because all the team physicians are aware of it, and the players are reporting it," Berger said. "We're also seeing that there is increased scrutiny on the sidelines."
In recent years, a growing body of evidence about the devastating long-term effects associated with concussions has been strengthened by reports of former football players suffering cognitive problems and showing signs of dementia in their 40s and 50s.
Researchers at the Center for the Study of Traumatic Encephalopathy at Boston University have been studying the brains of deceased football players and found evidence of chronic traumatic encephalopathy (CTE), a progressive disease that eventually kills brain cells and affects the parts of the brain that control emotion, rage, hyper-sexuality and even breathing.
Studies also revealed brown tangles throughout the brain tissue of the NFL players who died in their 30s or 40s, resembling those that might be found in the brain of an 80-year-old with dementia.
"The way to look at a concussion, is that there is a force applied to the brain. And in between the skull and the brain there's spinal fluid so the brain can rotate, go side-to-side, or it can go back-and-forth or twist," said Berger. "That back-and-forth or twisting motion causes a temporary interruption in the transmission of neural signals."
With a severe concussion, you can actually sever or shear a neuron, and we're able to see that in an electroencephalogram (EEG) or a scan, Berger added.
But professional athletes are not necessarily the highest risk group for suffering the damaging effects of concussions.
Each year, an estimated 300,000 football-related head injuries occur in the United States with 45,000 of them being requiring treatment in a hospital emergency room in 2009 alone, according to the American Association of Neurological Surgeons.
And that's just in football. The number of sports-related head injuries in children and teens is growing, raising concern among doctors and parents.
Between 1997 to 2007, emergency room visits for concussion in kids aged 8 to 13 playing organized sports doubled. And in older teens, that number increased by more than 200 percent, according a report released by the American Academy of Pediatrics.
"There's a much greater concern for younger athletes when they have a concussion in a season and the risk for another is increased," said Berger.
Click here to read more about concussions in sports from the CDC.