PLoS ONE (Jan 2024)

Sub-concussive head impacts from heading footballs do not acutely alter brain excitability as compared to a control group.

  • Raphael Hamel,
  • Baptiste Maxime Waltzing,
  • Tom Massey,
  • James Blenkinsop,
  • Leah McConnell,
  • Kieran Osborne,
  • Karamo Sesay,
  • Finn Stoneman,
  • Adam Carter,
  • Hajar Maaroufi,
  • Ned Jenkinson

DOI
https://doi.org/10.1371/journal.pone.0306560
Journal volume & issue
Vol. 19, no. 8
p. e0306560

Abstract

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BackgroundRepeated sub-concussive head impacts are a growing brain health concern, but their possible biomarkers remain elusive. One impediment is the lack of a randomised controlled human experimental model to study their effects on the human brain.ObjectivesThis work had two objectives. The first one was to provide a randomised controlled human experimental model to study the acute effects of head impacts on brain functions. To achieve this, this work's second objective was to investigate if head impacts from heading footballs acutely alter brain excitability by increasing corticospinal inhibition as compared to a control group.MethodsIn practised and unpractised young healthy adults, transcranial magnetic stimulation was used to assess corticospinal silent period (CSP) duration and corticospinal excitability (CSE) before and immediately after performing headings by returning 20 hand-thrown balls directed to the head (Headings; n = 30) or the dominant foot (Control; n = 30). Moreover, the Rivermead Post-Concussion Questionnaire (RPQ) was used to assess the symptoms of head impacts. Head acceleration was also assessed in subgroups of participants.ResultsThe intervention lengthened CSP duration in both the Headings (6.4 ± 7.5%) and Control groups (4.6 ± 2.6%), with no difference in lengthening between the two groups. Moreover, CSE was not altered by the intervention and did not differ between groups. However, performing headings increased headaches and dizziness symptoms and resulted in greater head acceleration upon each football throw (12.5 ± 1.9g) as compared to the control intervention (5.5 ± 1.3g).ConclusionsThe results suggest that head impacts from football headings do not acutely alter brain excitability as compared to a control intervention. However, the results also suggest that the present protocol can be used as an experimental model to investigate the acute effects of head impacts on the human brain.