Assessment of high velocity head impacts using transcranial magnetic stimulation in Australian national ice hockey players: a multiple-case study
Bibliographic record
Abstract
Comprising of eight teams, players in the Australian Ice Hockey League (AIHL) are elite, attracting college players from the United States and Canada, as well as former professional players from European and American Leagues up to the standard of the National Hockey League (NHL). To date, no study has tracked in-game head impacts with follow-up measures in AIHL players. The aim of this multiple-case study was to investigate neurophysiological responses using transcranial magnetic stimulation (TMS) following high impact events over the course of the 2016 AIHL season. Data was collected from 11 male players (28.8 ± 6.8 years) recruited from one AIHL team. Using previously published methods for concussion studies,1, 2 TMS (MagVenture, Denmark) was used to quantify corticospinal excitability, via motor evoked potential (MEP) amplitude and intracortical inhibition from TMS cortical silent period (cSP). Players who had registered a high threshold event (66 g or 4500 rads/s2) during the game using impact sensors (X2 Biosystems, USA) were compared at three and 10 days, to their baseline measures. Six players sustained in-match impacts of greater than 66 g or 4,500 rads/s2 (mean in- match linear acceleration of 93.48 ± 21.68 g; mean rotational acceleration of 12,532.76 ± 4,682.76 rads/s2). All six players showed no immediate signs or symptoms of concussion post-match. Clinical follow up, at three days post-match, revealed five of the six players were asymptomatic. However, three of these players showed an increase in cSP between 6.7 ms to 10.6 ms, returning to baseline levels by 10 days. Despite no immediate symptoms, one athlete who sustained a 98.8 g/19,703.89 rads/s2 impact was found to have delayed symptoms of concussion in follow up clinical assessment and testing at both three and 10 days post-match. This player demonstrated no change in MEP amplitude but displayed an increased cSP of 20.8 ms at three days, remaining increased by 23.98 ms at 10 days, in comparison to baseline. The findings of this study reinforce previous TMS studies investigating corticospinal responses during the acute recovery phase following concussion.1-3 This multi-case study illustrates measureable changes in corticospinal excitability associated with high impact head trauma that may not manifest as concussion immediately, and can also be an adjunct to follow up clinical assessment for return to play decisions.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".