Baseline Neuropsychological Tests: Getting Valid Results Poses Challenge

Along with studies reporting high concussion rates, increased concussion awareness among athletes, parents, coaches and health care providers, and new state concussion safety laws has come rapid growth in the use of computerized neuropsychological testing to evaluate and manage sports concussions, particularly at the college and high school levels. 

By establishing an athlete's baseline or "normal" score on tests of cognitive functions that are often affected by concussion, such as memory, processing speed, reaction time, and attention, and on measures of physical/emotional/cognitive symptoms, re-testing after a suspected concussion can help determine if and when an athlete's brain has recovered. If the youth feels symptom free, and post-concussion testing is the same or better than baseline (pre-concussion) testing, recovery is imminent.

At least that's the way it's supposed to work.

In practice, however, I have unfortunately found in treating athletes after concussion that too many arrive at my office with invalid baseline test results from their schools: baseline scores that can't be used, because they don't provide an accurate snapshot of a child or teen's pre-concussion or normal cognitive functioning, and so can't be used to measure the degree of post-concussion cognitive impairment and recovery.  Two research papers - one on which I am lead author,¹ the other on which I am a co-author,² confirm my anecdotal experience as a clinician, suggesting that between 6 and 12% of baseline tests may be invalid.  An earlier study of college athletes reported a rate of up to 25% invalid baselines.³

Factors leading to invalid baseline test results

Baseline test results can be invalid for a variety of reasons. The most obvious - recently highlighted by the media in professional sports - occurs when athletes intentionally perform poorly on their pre-season tests in order to establish low baselines that increase their chances of "passing" a post-concussion test and being medically cleared to return to play before their brains have actually healed.  Given the increased risk of a second concussion or, worse, a catastrophic brain injury from second impact syndrome, a youth athlete willing to fake a baseline test in order to return to a contact or collision sport too soon, to borrow a phrase, needs a wake-up call!

Most of the time, however, there tend to be other reasons for "invalids" among the youth athlete population.

Some of these reasons include:

1. Distractions during testing, especially when testing is performed in groups, in noisy settings, or with others in the room who are behaviorally acting out.
2. Reading difficulties or failure to pay attention to the instructions.
3. Attentional or learning difficulties that lead to inconsistent results [note: neuropsychological disorders, such as ADD/ADHD, are viewed as a so-called "modifying factor" in managing concussions by the most recent international consensus statement on concussion in sport.⁴
4. Lack of effort, negative attitude, or not taking the test seriously.
5. Fatigue, illness, or testing after an athletic practice or game.
6. Right-left confusion when using a computer mouse or keyboard.
7. Faulty equipment, such as a computer mouse that sticks or doesn't function properly.
8. Color blindness (especially if the test items require color discrimination).

Unfortunately, many baseline testing programs are conducted en masse in schools with limited athletic or school staff to oversee and review test results. As a result, baselines tend to be automatically stored in databases, but may not be looked at again until a concussion occurs. Some computerized neuropsychological tests now in use automatically identify or "flag" test results that may be invalid.

Advice to parents

So what should parents do to ensure that their child's baseline test is valid? 

My advice is to make sure that the people in charge of obtaining a baseline for your child:

1. Routinely review all baseline test results immediately afterwards and re-test when there is possible invalidity;
2. Know the test indicators that signal possible invalidity;
3. Thoroughly explain the test to your child before the test is taken and make sure he or she understands the instructions;
4. Provide a quiet, controlled environment for testing; and
5. Understand and control for the factors that may affect test results.

The bottom line is to remember that baseline test results that are invalid are useless at the time of post-concussion assessment.

 

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1. Moser RS, Schatz P, Neidzwski K, Ott S.D.  Does Group vs. Individual Administration Affect Baseline Neurocognitive Test Performance? Am. J. Sports Med. (in press)

2. Schatz P, Moser RS, Solomon GS, Ott SD,  Karpf R. Incidence of invalid computerized baseline neurocognitive test results in high school and college students. J. Ath Tr (in press)

3. Broglio SP, Ferrara MS, Macciochi SN, Baumgartner T A, Elliott R.  Test-retest reliability of computerized concussion assessment programs. J. of Ath. Tr. 2007;42(4):509-541.

4. Consensus Statement on Concussion in Sport: the 3rd InternationalConference on Concussion in Sport held in Zurich, November 2008. Br. J. Sports Med. 2009;43:i76-i84.

Updated June 4, 2011