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IMPACT TESTING FOR CONCUSSION

Timothy C. Hain, MD Page last modified: June 23, 2018 button Return to testing index

The IMPACT test battery is an online computerized neuropsychological test that produces standardized scores concerning memory, processing speed and impulse control. The test has been shown to be both reasonably sensitive and specific for concussion in athletes (Schatz et al, 2006). The test is much less costly than formal neuropsychological testing and also can be performed in less than an hour. It allows one to compare scores over time, which may be helpful in predicting recovery.

The test's use is also expanding to include other types of cognitive impairment such as hepatic encephalopathy (Tsushima et al, 2013).

The IMPACT test combined with computerized posturography is a reasonable method of assessing the consequences of a head injury to cognition and balance. The main problem, of course, is that there rarely is a pre-injury baseline. Both the IMPACT test and posturography have methods of detecting invalid tests.

What exactly is the ImPACT test good for ? Alsalaheen et al (2013) reviewed 69 studies. They stated "Although the convergent validity of ImPACT was supported, evidence of discriminant and predictive validity, diagnostic accuracy and responsiveness was inconclusive. The utility of the ImPACT test after acute symptom resolution was sparse. The review found many factors influenced the validity and utility of ImPACT scores. " So essentially, its better than nothing.

Alaslaheen et al (2016) also criticized the Impact test again and stated "Given the poor to moderate reliability of most ImPACT scores, clinicians should be cautious when ImPACT is used as a criterion for medical clearance to return to play after concussion. Because of its widespread use in concussion-related clinical research, researchers must exercise due diligence when utilizing ImPACT to evaluate outcomes after concussion or to validate other outcome measures."

Invalid testing (ImPACT):

The prevalence of invalid testing on the IMPACT testing is high in younger individuals. According to Abeare et al(2018), in a study of normal athletes undergoing "baseline" testing, more than half aged 10-21 years old failed at least one of four validity indicators. About 84% of athletes between the age of 10-14 failed at least one validity indicator. These are individuals who have no motivation to malinger. It suggests that validity norms should be age-normed, and also that invalidity indicators should be taken with several "grains of salt" in athletes between the ages of 10-14.

Invalid scores are also common in college athletes, according to Szabo et al (2013). 28% of scores post concussion suggested "invalid". Walton et al (2018) als pointed out a rather high prevalence of invalidity (16%) in University athletes. Invalid scores are also more common in students with academic difficultlies (Manderino et al, 2018).

Norms:

The ImPACT test is "normed" for various age groups. Tsushima et al (2018) suggested that norms should be used for age, sex, and ethnicity. However, this suggests that this test can somehow be used as a diagnostic tool. We ourselves think that it is a severity tool, and mainly has meaning on retest. Gardner et al (2012) felt that a single ImPACT test was not useful in managing sports concussion.

We offer IMPACT testing for individuals with concussions in our dizziness practice. We think it is mainly useful for measuring the rate of recovery.

BNA test.

We were recently (2015) puzzled to get an advertisement from Athletico Physical therapy for "BNA" testing. BNA was defined as "Brain Network Activity". We wondered - -what is BNA testing ? And why is a physical therapy chain testing brain networks -- we thought that physical therapists took care of physical injuries. We didn't think that they diagnosed brain networks, or for that matter, treated brain networks. The advertisement is here.

It turns out that BNA testing is an a computerized EEG, marketed for concussion management. EEG's are electroencephalograms -- a measure of brain electrical activity.

It seems to us that BNA testing is a diagnostic procedure, similar to the QEEG or brain mapping, that is sometimes offered in Chiropractic settings. As a very experienced neurologist, who has 30+ years of experience caring for patients with vestibular disorders, I have no idea at all what I would do with a QEEG or BNA test result. It would be entirely useless to me.

Furthermore, I also don't see why a physical therapy chain, such as Athletico, is doing brain wave testing.Why not have opticians testing brain networks too ? Or perhaps podiatrists ? After all, the brain is involved with everything.

As the saying goes -- Caveat Emptor.

The King-Devick test

Yet another online concussion test is the "King-Devick" test. This one is marketed through the Mayo Clinic. It is quicker and easier than the Impact test. According to Tjarks et al (2013), "Cognitive visual performance testing using KD has utility in concussion evaluation. Validation would further establish KD as an effective ancillary tool in longitudinal concussion management and research." In other words, the KD test might be useful, but nobody has proven that it is valid.

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Copyright June 23, 2018 , Timothy C. Hain, M.D. All rights reserved. Last saved on June 23, 2018