Subconcussive head impacts affect neuro-ophthalmologic function
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Neuro-ophthalmologic function is affected by subconcussive head impacts which may affect individuals participating in contact sports, according to a randomized clinical trial.
“The data from this randomized clinical trial confirm previous findings on the oculomotor impairment after subconcussive head impacts and generate new evidence that repetitive subconcussive head impacts can impair neuro-ophthalmologic function,” the study authors wrote.
Participants were aged 18 to 26 years with at least 5 years of soccer ball heading experience. Thirty-six were randomized to a soccer ball heading group and 31 to a kicking control group.
Both groups were administered the King-Devick test (KDT) to examine neuro-ophthalmologic functional integrity at set time points through 24 hours after a bout of 10 soccer ball headers or kicks. The researchers hypothesized that “10 bouts of soccer ball heading will significantly increase (worsen) [near point of convergence], which would persist for longer than 24 hours, while the NPC of control participants who kicked a ball would remain consistent throughout the study point.”
The kicking group performed faster on the KDT than the heading group after 10 headings with a difference at 0 hours (2.2 seconds faster), 2 hours (2.8 seconds faster) and 24 hours (2.0 seconds faster).
NPC results for the heading group were greater than for the kicking group at 0 hours (P < .001), 2 hours (P = .03) and 24 hours (P = .02).
“These findings indicate that even mild head impacts can induce impairments in neuro-ophthalmologic function that can persist for at least 24 hours,” the researchers wrote. “Our data highlight that 10 impacts are sufficient to cause mild oculomotor impairment, calling for a standardization guideline to monitor athletes’ safety.” – by Erin T. Welsh
Disclosures: The authors report no relevant financial disclosures.
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Roberto Warman, MD
KDT, or King-Devick Test, is designed to rapidly asses neuro-ophthalmic functional integrity by performing a total of 145 saccades while rapidly reading numbers aloud in a tablet. It is widely used in sports when an athlete suffers a concussion or concussion-like impact in order to asses if they can return to the field successfully.
This study has shown that subconcussive head impacts in a controlled process will affect the KDT test and the near point of convergence for at least 24 hours in the absence of clinical symptoms.
How do ophthalmologists use this information in clinical practice? KDT testing is a screening in the athletic field, not a substitute of an adequate ophthalmic examination. However, ophthalmologists can counsel patients particularly high school and college students, of the proven consequences of repetitive head trauma and its consequences and suggest taking precautionary actions and/or limitations to diminish damage. Ophthalmologists should also question patients regarding sport injuries and concussion history if evaluation discloses abnormal oculomotor integrity and refer for
neuro-ophthalmic evaluation as needed. Ophthalmologists and their respective associations should be advocates of safety in sports and protection of young prospective athletes on the basis of solid data, definitely proving cumulative damage in repetitive head trauma.
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