Do children and adolescent ice hockey players with and without a history of concussion differ in robotic testing of sensory, motor and cognitive function?

The study was cross-sectional, so it compared players at one time and did not measure them before and after concussion. Many players were tested long after concussion: the median time since last concussion was 480 days, with a range of 8 to 3330 days. Concussion history was self-reported by children and parents, so some players may have been misclassified. Players without a reported history could still have had an undiagnosed concussion, which would make the two groups more similar. The analysis used group means, so it could miss individual impairments that were present in only a few players. The sample was a convenience sample of ice hockey players aged 10 to 14 and was mostly male, with 93% of the no-history group and 97% of the concussion-history group reported as male. Age and handedness affected some robot scores, but the authors say the sample size did not support including them as covariates in the primary analysis. The authors say the study may have been underpowered, so a null primary result does not prove there was no difference. Reference ranges were based on healthy controls, and normal human variability can make it hard to tell whether one person’s score is abnormal.

Funding was named from Canadian Institutes of Health Research, the Talisman Energy Fund in support of Healthy Living and Injury Prevention, and the Alberta Children’s Hospital Research Institute for Child and Maternal Health. BKIN Technologies Ltd is named as the maker of the KINARM robot. No author conflict-of-interest declaration is supplied.

Do not read the null result as proof that concussion has no lasting motor or cognitive effects. The study compared group means long after injury, used self-reported concussion history, and the authors say individual impairments could have been masked or the study may have been underpowered.