How Concussion Testing Affects Mental Fatigue Levels

This piece, by Onno Berkan, was published on 01/28/25. The original text, by Barwick et al., was published by the Journal of Clinical Neurophysiology on 02/2012.

This Penn State study examined how subjects’ mental fatigue is affected during typical concussion testing procedures. The researchers worked with healthy, athletically active college students with no history of brain injuries or other neurological conditions. This was important because while fatigue is a common symptom after sports concussions, there hasn't been much research to understand how the testing might contribute to feeling tired, affecting results.

The study involved a 90-minute testing session during which participants completed various mental tasks while their brain activity was monitored. The researchers measured three main aspects: how tired participants felt (through self-reporting), how well they performed on cognitive tests, and their brain activity patterns using EEG recordings. The main test used was the Stroop task, which required participants to read color words and name the color of the text—a task that can be mentally taxing when performed quickly.

The results showed several significant findings. First, participants reported feeling significantly more tired after completing the testing session, experiencing mental and physical fatigue. While they got faster at performing the tasks due to practice, they made more mistakes on the more challenging portions of the test, suggesting that fatigue affected their performance. The brain activity measurements also showed notable changes, including increased theta wave activity in the front and center of the brain, a known indicator of mental fatigue.

What makes these findings particularly significant is that even healthy college students showed measurable signs of fatigue just from taking the standard concussion assessment tests. This data creates an important consideration for doctors, as the fatigue from the testing itself might be confused with symptoms of a concussion. Previous research had not thoroughly examined how non-injured people respond to these lengthy assessment procedures, making it difficult to distinguish between normal testing fatigue and actual concussion symptoms.

The research demonstrated that even a relatively short 90-minute testing session can produce significant mental fatigue, as evidenced by multiple measures, including brain activity changes, decreased performance accuracy, and increased subjective tiredness. The study provides an essential baseline for understanding normal fatigue during concussion testing. It could be replicated with athletes to measure baseline and post-concussion fatigue differences.

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