The computer screen shows a single wavy line. Later, the screen displays one simple word, such as "ice," in large, bold print. Then there are a series of mixed-up X's and O's.

It's all part of a test used to help diagnose a concussion as well as better understand its effect and the time it takes for the injury to fully heal.

In the verbal exam, the person who sees ice on the screen must be able to pick out the word in a list shown later. The wavy line tests visual memory.

It's not meant to be complicated, Mark Lovell said. "The more complicated things are, the less useful they usually are," he said.

Lovell is a cocreator of the ImPACT test. ImPACT stands for Immediate Post-Concussion Assessment and Cognitive Testing. The test, which takes about 20 minutes, measures skills such as attention span, verbal memory, visual memory, reaction time, and impulse control.

After seeing 12 of those simple "target" words for 750 milliseconds each, the test-taker is presented with a list of 24 words, including the 12 he just saw. The test-taker simply has to identify the 12 target words among the 24.

The test, used in dozens of area high schools, first serves as a baseline test administered to athletes who might be at risk of suffering a concussion.

After an athlete suffers a concussion, the test is taken again. If the athlete's score deviates too far from the baseline score, the athlete shouldn't be playing sports.

"We're using this to get, essentially, a fingerprint of the person so in any event that they're injured, we can do a more elegant analysis of the recovery," Lovell said.

Lovell, director of the UPMC Center for Sports Medicine concussion program, and Joseph Maroon, the team neurosurgeon for the Pittsburgh Steelers, developed ImPACT in the early 1990s.

Not much has changed about the test since that time except for the number of people using it.

Every NFL, NHL, and Major League Baseball team uses the test. The trickle-down effect led a large number of college athletic programs to use the test, too. But at its core, Lovell said, the test was designed for younger athletes.

"People will ask me, 'Why didn't you use touch-screen technology? Why didn't you use fancier equipment?' And the reason is quite simple: because nobody would use it," Lovell said. "Nobody would be able to afford it. The goal has always been to make this applicable to younger kids. That's always been the driving goal."

With use of the test growing, Lovell said, the focus now must shift to education.

Lovell was adamant that the test not be the only factor in diagnosing a concussion and treating the athlete. He said he spends about 80 percent of his time training other doctors how to recognize and treat the injury.

"And a part of that process is ImPACT," he said. "But it's certainly not the whole part."

Bryan Ghee, head athletic trainer at St. Joseph's Prep, echoed Lovell's sentiments.

The Prep has been administering ImPACT since 2006. And that has led to increased interplay among doctors, athletic trainers, and students, he said.

One of the most crucial aspects of the ImPACT test, Ghee said, is the section in which the athlete describes his or her symptoms and the nature of the injury.

"If they still have a high symptoms score [but are at their baseline on other sections of the test], that's a telling sign that they're not ready to play," Ghee said.

Schools can buy subscriptions in a number of different packages to administer the test. The most common are yearly subscriptions.

For example, the basic yearly subscription costs $500 and comes with 300 baseline tests and 90 post-injury tests. On top of that, the company provides an additional 150 baselines and 45 post-injury tests for the school to use at any time after the first year.

The company suggests that most students need to take the baseline test every other year; hence, most subscriptions are renewed every other year. The extra tests are meant for any new students the school wants to test between subscriptions.

"I think it's a great tool in assisting a trainer or a student-athlete's physician in making a diagnosis," Haddonfield athletic director Lefty Banos said.

Haddonfield, like many schools, tests athletes only in contact sports. The school pays for ImPACT with donations from the booster clubs of the sports that use the test.

Lovell considers himself a big sports fan and an advocate of children playing sports. The last thing he said he wants is for his test to promote fear among students and parents. In fact, Lovell said, the test should do just the opposite.

"We believe, and the research out there goes along with it, that the vast majority of people who have concussions make a full recovery and can go back to playing sports," Lovell said. "And that's one of the reasons we have the ImPACT test. I think it can actually make parents feel better about where their child is at. It helps when they see that the child has gone back to their baseline, instead of just wondering."