The Scenario: rubgy hit – felt a solid blow to the noggin. Shaken up but feeling mostly OK. The trainer asked me to look at her finger and follow it left and right, up and down. It’s blurry and it made my headache worse but I think I did OK. She thinks I have a concussion. What did she see with that test?
Concussions. In the literature they’re classified as mild traumatic brain injuries. There are a lot of different systems to assess in someone suspected of suffering from a concussion injury – the muscles/ligaments/joints/and spatial awareness (ie. proprioceptor) sensors within the neck, the vestibular/inner ear, the visual system, the neurocognitive/processing system; even the presence of anxiety or a previous history of migraines can play a role in how the concussion injury will ultimately play out. With so many systems in play, this post will in no way touch upon how to assess them all, but a blurb on how easily a quick vestibular/ocular motor assessment – ie. how your eyes move – on diagnosing a concussion will hopefully shine some light on why we do this.
Several studies have shown that approximately 30% of people experiencing a concussion injury report some sort of visual problem within the first week of their injury. 1,2 However, up until 2014, the majority of on-field concussion assessment tools didn’t have a way of adequately assessing the quality of this visual movement.3
Then came a paper published by Anne Mucha and her colleagues from the University of Pittsburgh in 2014. Anne and her team developed a Vestibular/Ocular Motor Screening (VOMS) assessment that consisted of 7 tests requiring no more than a metronome and a tape measure, and of which could be completed on the field within 5 – 10 minutes from start to finish. After each of the 7 tests, individuals are asked to rank their symptom intensity on a scale of 0 (no symptoms) to 10 (severe symptoms) on 4 different symptoms: headache, dizziness, nausea, and fogginess – and then the total scores for either each test (a score out of 40) or the whole test (a score out of 320) can be calculated.
So, how good was this VOMS test at detecting a concussion?
Turns out, pretty darned good.
The Experiment: use the VOMS to assess those with a concussion (64 people – all assessed on average within 5.5 days of sustaining the concussion injury) and 78 healthy controls – and examine if the VOMS assessment could correctly identify between those with and without a concussion.
The Findings: assuming an initial 50/50 probability (ie. no better than chance) of correctly identifying someone with a concussion, when any 1 of the 7 tests increased the person’s symptoms by ≥2 intensity points, the probability of correctly identifying a concussed individual from a healthy control increased from 50% to 96%.
That is a pretty powerful stat.
I don’t want to oversimplify the complexities of concussion assessment, or discredit the nuances that need to be interpreted during a concussion assessment, but a quick reliable assessment tool that can help you make the right in-game call to pull your player and seek help is worth knowing about.
References:
Lovell MR, Iverson GL, Collins MW, Podell K, Johnston KM, Pardini D et al. “Measurement of symptoms following sports-related concussion: reliability and normative data for the post-concussion scale.” Applied Neurophysiology 2006;13(3):166-174.
Kontos AP, Elbin RJ, Schatz P, Covassin T, Henry L, Pardini J et al. “A revised factor structure for the post-concussion symptom scale: baseline and postconcussion factors.” American Journal of Sports Medicine 2012;40(10):2375-2384.
Mucha A, Collins MW, Elbin RJ, Furman JM, Troutman-Ensecki C, DeWolf RM, et al. “A brief vestibular/ocular motor screening (VOMS) assessment to evaluate concussions: preliminary findings.” American Journal of Sports Medicine 2014;42(10):2479-2486.