Jun 4, 2015New Studies Add to Concussion Debates
One of a pair of studies by Canadian researchers found that vestibulo-ocular dysfunction is predictive of a prolonged recovery from concussion in child and adolescent athletes. Another study found that neuroimaging can be helpful in some return-to-play decisions, despite not being very useful in diagnosing concussions. The work was done by the Canada North Concussion Network in Manitoba and recently appeared online ahead of print in the Journal of Neurosurgery: Pediatrics.
In the study on vestibulo-ocular dysfunction (VOD), Dr. Michael J. Ellis and his colleagues reported that 62 percent of athletes who suffered from post-concussion syndrome, which they defined as reporting concussion symptoms more than a month following their injury, also showed signs of VOD. They also found that the risk of developing post-concussion syndrome was statistically significantly higher in concussed patients who showed signs of VOD in the 30 days following the injury than in those who did not.
Although there is no standardized definition for VOD, the researchers defined it as “more than one subjective complaint of intermittent blurred or double vision, visual disturbance, gaze instability or difficulty focusing, dizziness, difficulty reading, or motion sensitivity” in conjunction with more than one abnormality in eye movements or vestibulo-ocular reflexes identified by a neurosurgeon during a physical examination.
In a press release from the Journal of Neurosurgery: Pediatrics announcing the study, the researchers said:
“While these tools may help physicians identify those patients at an elevated risk of post-concussion syndrome, they should not be regarded as stand-alone tools to be used to diagnose or manage concussion. Indeed, many serious and life-threatening neurological conditions can present with vestibular and oculomotor signs and symptoms similar to those observed in patients with sports-related concussion. Future research is needed to confirm the findings of this study, identify clinical predictors of vestibulo-ocular dysfunction, and evaluate the effect of targeted vestibular and oculomotor rehabilitation strategies on the objective findings responsible for persistent concussion symptoms.”
Canada North’s other study found that 78 percent of children and adolescents with concussions had normal imaging results, confirming the previous view that neuroimaging is not an effective tool for diagnosing them. They did say that imaging can be useful in some situations, including pediatric patients with focal neurological deficits, worrisome symptoms, or abnormal or inconclusive CT findings, and those with persistent symptoms for which the definition is unclear.
“This study provides preliminary evidence that neuroimaging findings are normal in a significant proportion of pediatric sports-related concussion patients, but not every patient, and that neuroimaging can be helpful in informing clinical and return-to-play decision making in selected patients presenting with neurological symptoms following sports-related head injury,” Ellis said in a release announcing the study. “Methodologically, this study does not tell us which patients are more likely to demonstrate traumatic abnormalities on clinical neuroimaging, including magnetic resonance imaging. This question will be addressed by a prospective clinical study that is currently underway at our institution.”