CHARLOTTE, N.C. -- NASCAR is reviewing with its medical experts all aspects of how it deals with concussions, including baseline testing that the IndyCar Series and other contact sports use.

For former Sprint Cup driver Steve Park, it can't come soon enough.

Park suffered a massive brain injury in a 2001 Nationwide Series crash at Darlington. He took the ImPACT baseline test in 2003 on the recommendation of NASCAR physician Dr. Jerry Petty after suffering a second concussion.

Because Park never had a test before that for comparison, there was no way to determine the full extent of his injury. He has wondered for years why NASCAR hasn't made the test a part of its preseason health exam.

"I am a big proponent in NASCAR that the ImPACT test, if it was part of your physical exam as a driver and you had it at the liaison office at every track, if you did get hurt during testing, qualifying or practice you could easily take the test (again) in 20 or 30 minutes and they could have a competent evaluation if you're hurt or not,'' Park told ESPN.com.

The subject of preseason baseline testing surfaced Thursday when Dale Earnhardt Jr. did not get medical clearance to drive in this past Saturday's Sprint Cup race at Charlotte Motor Speedway and Sunday's race at Kansas due to multiple concussions suffered over the past six weeks.

NASCAR does not perform baseline testing as a regular part of its preseason physical but plans to consult with its medical staff to see whether it should be added after what has happened to its most popular driver.

"We are always evaluating and reviewing our policies and procedures, especially when it comes to safety,'' NASCAR spokesman Kerry Tharp said. "We will continue to work closely and review our policies with the medical experts that advise NASCAR on baseline testing and other medical issues.

"While not mandatory, baseline testing can and has been used and is just one of the many tools a neurologist or neurosurgeon may use as part of a neurological assessment.''

The test gives physicians a starting point to learn if there is a loss of function after a head injury. It enables them to determine if a concussion has occurred and the severity of it.

Earnhardt did not have a baseline test after his Aug. 29 wreck at Kansas that registered 40 G-forces or immediately after his wreck at Talladega Superspeedway that registered 20 G's. Even if he had, there would have been no way to determine the full extent of the concussion because there was no baseline test taken before the injury that resulted in headaches, one of the symptoms of a head injury.

Danica Patrick, making the transition from IndyCar to NASCAR, would be in favor of baseline testing.

"We need to do whatever it takes to know more about injuries for sure,'' she said. "Every other year we did a baseline test (in IndyCar). Then if you had an accident, you took it. We also wore accelerometer ear pieces so they could measure, read and know more about the accident and how hard you hit. Anytime you're doing something to know more is a good thing.

"Yeah, I think it's a good thing.''

One of the arguments against baseline testing is athletes can manipulate the test with slow reaction times. Then, in case of a head injury, they run a lower risk of being parked as Earnhardt was, taking him out of championship contention.

"But here's what I think about that,'' Patrick said. "Your competitiveness comes out in it that you want to do well. That's what I thought, anyway. You can sandbag it for sure. If you do, then you're only cheating yourself.''

The ImPACT test was developed by Mark Lovell, the director of the Center for Sports Medicine Concussion Program at the University of Pittsburgh Medical Center.

ImPACT stands for Immediate Post-Concussion Assessment and Cognitive Testing.

"Before we had tests like ImPACT, a lot of it came down to what the athlete told you," Lovell said in a 2003 article. "You'd ask: 'Do you have a headache? Do you feel nauseous? Do you feel dizzy?' They generally say no to all of those.

"One thing we know about athletes is they're very, very competitive. So we weren't absolutely positive we were always being given an accurate picture of how they were feeling. With a test like ImPACT, you can't cheat it."

The test takes about 22 minutes the first time and a little less in future uses. It measures memory, reaction time, mental speed, information processing, anticipation time and other functions of the brain affected by concussions.

By taking the test prior to a head injury, a baseline can be set by which to measure further tests.

"Say your personal score is 1500 (before injury),'' Park said. "That goes in your record. Now afterwards, if you have a head injury and come back and take the test and score a 350 ... they can look at where you were not doing well and say, 'This is what's impaired.'"

Park wishes he'd known about the test before his 2001 crash that forced him to miss the last eight races of that season and the first four of 2002. He said drivers should "understand the importance" of the test.

"We're so used to an open bleeding wound, you're hurt, you need stitches, let's evaluate it,'' Park said. "When you have a closed-head injury, you can MRI your head and none of those pictures tells the story of how your brain is functioning. (Baseline testing) is something they need to look at."