NFL's concussion carousel in full motion Week 1

Another NFL season begins, and the concussion carousel already is spinning.

Green Bay Packers running back Eddie Lacy was concussed in the league opener Thursday night, and has started the NFL mandated process of determining when he's ready to return.

Houston Texans rookie linebacker Jadeveon Clowney -- the No. 1 pick overall in May's draft -- and Baltimore Ravens running back Bernard Pierce -- both coming off concussions -- await Sunday openers.

Denver Broncos wide receiver Wes Welker hoped to return from a concussion this week, but instead is sidelined due to a four-game suspension after a violation of the NFL's substance abuse policy

Pierce says he'll put his faith in "pretty intense" medical screening and not worry about protecting his head when he starts against the Cincinnati Bengals.

"You just put it in the back of your mind and go," says Pierce, the replacement for Ray Rice, suspended two games for a domestic violence case.

Lacy, who suffered his second concussion in a year, entered the NFL system in place since 2009. It says no player may return until they are symptom free, have passed baseline tests of brain function and have been cleared by the team doctor and an outside neurological consultant.

"We're always going to go through the process,'' Packers coach Mike McCarthy said.

But for all the heightened scrutiny and new measures, deciding when it's right to return to play after a concussion remains a work in progress.

Doctors are focused on identifying issues that may linger even when a player is cleared. There are concerns about potential long-term effects if a player comes back too soon. Researchers are looking into MRI (magnetic resonance imaging) as a potential tool to find "biomarkers" in the brain that could signal that a player needs more recovery time.

Return to play was a key focus when the NFL hosted a recent "think tank" for medical representatives of sports agencies from around the nation and world.

"The big issue in concussions is when is it safe to return a player back to the sport or back to exercising? And the fact of the matter is we really don't know the correct answer," says Richard Ellenbogen, neurosurgeon and co-chairman of the NFL Head, Neck and Spine Committee.

Ellenbogen says the group aims to support collaborative research across sports to find better, more scientific strategies.

Before Welker's suspension, he was recovering from his third concussion in 10 months.

"Concussion is a manageable condition. We can get athletes back to play safely in the right way," says Michael Collins, executive director of the Sports Concussion Program at the University of Pittsburgh Medical Center.

Three in succession?

"The first question the clinician has to answer is why because that's statistically way out of bounds in terms of what the incidence level is with the injury," says Collins.

UNRESOLVED ISSUES

Not that three concussions in relatively short span are unheard of. Collins hasn't examined Welker, but he's seen this.

"I bet I see a patient every day like this that's had three concussion," says Collins. "Whether it's a high school kid or a junior high kid or a professional athlete or college athletes."

He says some cases may be linked to pre-existing conditions. For example, somebody with a history of migraines may be more concussion prone. It could also be playing style, using the head.

"Or is there an unresolved issue (from a previous concussion) that hasn't been treated that leads them to be more vulnerable?" says Collins. " … If there is an unresolved issue, we find that less biomechanical force will cause re-injury.''

He says unresolved issues can occur in the vestibular system, a network that includes sensory organs in the inner ear that are involved with balance and vision when the head moves. He says there testing methods to identify such issues and vision and balance therapies to address them. He says the key is to identify what's happening.

"I've retired athletes from one or two concussions, and I've let athletes with eight or nine concussions play if it's managed well," says Collins. "The first time I heard someone say, 'Oh, you've had three concussions, and I'm not sure you should play football again,' (I thought) that's a very naïve statement.''

When might he recommend retirement?

"If it's a constitutional factor, a personal history of this or that, there may not be a treatment for it," he says. " … If it's there and it keeps happening, those are the patients that unfortunately can't play because they keep getting concussed.''

LONG-TERM ISSUES

In a tentative settlement with about 5,000 former who filed concussion suits against the NFL, there are monetary awards for those who have suffered from such conditions as dementia, Alzheimer's and the degenerative brain condition chronic traumatic encephalopathy (CTE).

In the settlement, the NFL doesn't acknowledge the conditions are related to football. Players needn't prove the conditions are linked to NFL hits. Medical debate continues on the potential link between concussions and such conditions.

"Multiple concussions per se don't mean you're going to get CTE or long-term effects,'' says Julian Bailes, a neurosurgeon with the NorthShore Neurological Institute in the Chicago area and longtime CTE researcher.

But he says the potential is there for long-term effects.

"I think it's useful for people to understand that once you get a certain number (of concussions) then you worry about both short and long-term consequences," says Bailes.

Bailes also is interested in the potential long-term impact of the routine hits to the head that don't result in concussions.

"Some CTE sufferers didn't really have a history of concussions, including Junior Seau and the first case, Mike Webster," he says. "It was years of exposure (to hits) that we think led them to having the risk.''

Bailes says it "very difficult" to tell a player to retire.

"We don't want that to be the answer," he says. " … But we try to balance that with their years of exposure and what's happened to them in their sports medicine history."

BIOMARKERS

Teena Shetty, a neurologist at the Hospital for Special Surgery in New York, is researching use of MRIs to find "biomarkers" that identify what's happening in the brain after a concussion. The research is part of the Head Health Initiative, a collaboration of the NFL and General Electric.

"The problem we have right now … is that we have no objective scientific tool to distinguish how severe a concussion is and how long it's going to take someone to recover,'' says Shetty.

In the research, MRIs will be done within 72 hours on the brains of concussion victims. More imaging will be done at intervals over three months. They'll be looking at such things as water movement in the brain following concussions.

Shetty says they hope to find biomarkers to "correlate with a more complicated or prolonged recovery.''

She adds, "Certainly, some of the imaging markers that we see we hope to correlate with long-term complications."

Could it be useful in helping a player decide if it's time to quit?

"We don't know what will happen with the research, but certainly that's conceivable," says Shetty.

She, too, acknowledges the difficulty of such decisions. "Especially if it's somebody's livelihood or their main love in life," she says.

"Having said that, there are some cases that have seen multiple physicians and there is sort of a concurrence of opinion, which is that it is not suitable for this person to be in that sport. It would more that they've had a number of concussions, which becomes concerting because we don't fully understand the long term complications of multiple concussions, and that each concussion was particularly difficult for them to recover from."

FULL THROTTLE

The NFL reports it has averaged 247 concussions per season (preseason and regular season) over the past three years. Last year's total of 228 was down 13 percent from 2012.

Baltimore Ravens offensive lineman Jah Reid was concussed in practice in mid-August. "Soon as I felt the symptoms, I alerted our (athletic) training staff,'' says Reid.

He was diagnosed and went through the tests and examinations. He is cleared for Sunday. Does he worry about long-term effects?

"It's a concern. You want to be healthy later in life," says Reid. "I feel like they did an adequate job taking care of me … But, hey, you never know, and you can't worry about the future like that because there's very little you can do to control it. Just try to be healthy now and hope it pays off later."

Pierce was hit in the head during an Aug. 23 preseason game by safety Brandon Meriweather of the Washington Redskins. Meriweather was not penalized (Pierce was a runner, not covered by rules protecting receivers). The same game, Meriweather's hit on a receiver – plus a history of offenses – drew a two-game suspension.

Pierce's concussion left him with some dizziness and sensitivity to light. He had no memory loss: "I remember the play and everything."

He calls it a "minor" concussion.

"I started practicing the week after and am full throttle now,'' he says.