A Comparison of Cognitive Function in Former Rugby Union Players Compared with Former Non-Contact-Sport Players and the Impact of Concussion History



This study investigated differences in cognitive function between former rugby and non-contact-sport players, and assessed the association between concussion history and cognitive function.


Overall, 366 former players (mean ± standard deviation [SD] age 43.3 ± 8.2 years) were recruited from October 2012 to April 2014. Engagement in sport, general health, sports injuries and concussion history, and demographic information were obtained from an online self-report questionnaire. Cognitive functioning was assessed using the online CNS Vital Signs neuropsychological test battery. Cohen’s d effect size statistics were calculated for comparisons across player groups, concussion groups (one or more self-reported concussions versus no concussions) and between those groups with CNS Vital Signs age-matched norms (US norms). Individual differences within groups were represented as SDs.


The elite-rugby group (n = 103) performed worse on tests of complex attention, processing speed, executive functioning, and cognitive flexibility than the non-contact-sport group (n = 65), and worse than the community-rugby group (n = 193) on complex attention. The community-rugby group performed worse than the non-contact group on executive functioning and cognitive flexibility. Compared with US norms, all three former player groups performed worse on verbal memory and reaction time; rugby groups performed worse on processing speed, cognitive flexibility and executive functioning; and the community-rugby group performed worse on composite memory. The community-rugby group and non-contact-sport group performed slightly better than US norms on complex attention, as did the elite-rugby group for motor speed. All three player groups had greater individual differences than US norms on composite memory, verbal memory and reaction time. The elite-rugby group had greater individual differences on processing speed and complex attention, and the community-rugby group had greater individual differences on psychomotor speed and motor speed. The average number of concussions recalled per player was greater for elite rugby and community rugby than non-contact sport. Former players who recalled one or more concussions (elite rugby, 85 %; community rugby, 77 %; non-contact sport, 23 %) had worse scores on cognitive flexibility, executive functioning, and complex attention than players who did not recall experiencing a concussion.


Past participation in rugby or a history of concussion were associated with small to moderate neurocognitive deficits (as indicated by worse CNS Vital Signs scores) in athletes post retirement from competitive sport.

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  1. 1.

    McCrory P, Meeuwisse WH, Aubry M, Cantu B, Dvořák J, Echemendia RJ, et al. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport held in Zurich, November 2012. Br J Sports Med. 2013;47(5):250–8.

    Article  PubMed  Google Scholar 

  2. 2.

    King D, Gissane C, Brughelli M, Hume PA, Harawira J. Sport-related concussions in New Zealand: a review of 10 years of Accident Compensation Corporation moderate to severe claims and costs. J Sci Med Sport. 2014;17(3):250–5.

    Article  PubMed  Google Scholar 

  3. 3.

    England Professional Rugby Injury Surveillance Project Steering Group. England Professional Rugby Injury Surveillance Project 2013–2014 Season Report. Twickenham. 2014.

  4. 4.

    Theadom A, Starkey NJ, Dowell T, Hume PA, Kahan M, Feigin V. Sports-related brain injury in the general population: an epidemiological study. J Sci Med Sport. 2014;17(6):591–6.

    Article  PubMed  Google Scholar 

  5. 5.

    Quarrie KL, Murphy IR. Towards an operational definition of sports concussion: identifying a limitation in the 2012 Zurich consensus statement and suggesting solutions. Br J Sports Med. 2014;48(22):1589–91.

    Article  PubMed  Google Scholar 

  6. 6.

    Carney N, Ghajar J, Jagoda A, Bedrick S, Davis-O’Reilly C, du Coudray H, et al. Executive summary of concussion guidelines step 1: systematic review of prevalent indicators. Neurosurgery. 2014;75:S1–2.

    Article  PubMed  Google Scholar 

  7. 7.

    Kerr ZY, Register-Mihalik JK, Marshall SW, Evenson KR, Mihalik JP, Guskiewicz KM. Disclosure and non-disclosure of concussion and concussion symptoms in athletes: review and application of the socio-ecological framework. Brain Inj. 2014;28(8):1009–21.

    Article  PubMed  Google Scholar 

  8. 8.

    Gardner A, Iverson GL, Williams WH, Baker S, Stanwell P. A systematic review and meta-analysis of concussion in rugby union. Sports Med. 2014;44(12):1717–31.

    Article  PubMed  Google Scholar 

  9. 9.

    Kirkwood G, Parekh N, Ofori-Asenso R, Pollock AM. Concussion in youth rugby union and rugby league: a systematic review. Br J Sports Med. 2015;49(8):506–10.

    Article  PubMed  Google Scholar 

  10. 10.

    Broglio SP, Eckner JT, Paulson HL, Kutcher JS. Cognitive decline and aging: the role of concussive and subconcussive impacts. Exer Sport Sci Rev. 2012;40(3):138–44.

    Google Scholar 

  11. 11.

    Iverson GL, Brooks BL, Collins MW, Lovell MR. Tracking neuropsychological recovery following concussion in sport. Brain Inj. 2006;20(3):245–52.

    Article  PubMed  Google Scholar 

  12. 12.

    Iverson GL, Gaetzy M, Lovell MR, Collins MW. Cumulative effects of concussion in amateur athletes. Brain Inj. 2004;18(5):433–43.

    Article  PubMed  Google Scholar 

  13. 13.

    Hume PA, Quarrie K, Lewis G, Theadom A. IRB/NZR/AUT RugbyHealth project final report. A technical report to the International Rugby Board and New Zealand Rugby. Auckland: Sport Performance Research Institute New Zealand, Auckland University of Technology, New Zealand. 2015.

  14. 14.

    Saunders JB, Aasland OG, Babor TF, de la Fuente JR, Grant M. Development of the alcohol use disorders identification test (AUDIT): WHO collaborative project on early detection of persons with harmful alcohol consumption—II. Addiction. 1993;88(6):791–804.

    CAS  Article  PubMed  Google Scholar 

  15. 15.

    Gualtieri CT, Johnson LG. Reliability and validity of a computerized neurocognitive test battery CNS Vital Signs. Arch Clin Neuropsych. 2006;21(7):623–43.

    Article  Google Scholar 

  16. 16.

    Boyd A. CNS Vital Signs manual. 2015. http://www.cnsvitalsigns.com/WhitePapers/CNSVS-BriefInterpretationGuide.pdf. Accessed Feb 2015

  17. 17.

    Gualtieri CT, Johnson LG. Neurocognitive testing supports a broader concept of mild cognitive impairment. Am J Alzheimers Dis Other Demen. 2005;20(6):359–66.

    Article  PubMed  Google Scholar 

  18. 18.

    Hopkins WG. A scale of magnitudes for effect statistics. In: Hopkins WG (ed). A new view of statistics. 2002. http://www.sportsci.org/resource/stats/effectmag.html. Accessed 26 Jan 2009.

  19. 19.

    Alberts JL, Linder SM. The utilization of biomechanics to understand and manage the acute and long-term effects of concussion. Kinesiol Rev. 2015;4(1):39–51.

    Article  Google Scholar 

  20. 20.

    DeKosky S, Ikonomovic M, Gandy S. Traumatic brain injury: football, warfare, and long-term effects. N Engl J Med. 2010;363:1293–6.

    CAS  Article  PubMed  Google Scholar 

  21. 21.

    Hollis SJ, Stevenson MR, McIntosh AS, Shores EA, Collins MW, Taylor CB. Incidence, risk, and protective factors of mild traumatic brain injury in a cohort of Australian non professional male rugby players. Am J Sport Med. 2009;37(12):2328–33.

    Article  Google Scholar 

  22. 22.

    Shuttleworth-Edwards AB, Smith I, Radloff SE. Neurocognitive vulnerability amongst university rugby players versus noncontact sport controls. J Clin Exp Neuropsychol. 2008;30(8):870–84.

    Article  PubMed  Google Scholar 

  23. 23.

    West S. Substance abuse among persons with traumatic brain injury: a review. Neurorehab Neural Repair. 2011;25(1):3–8.

    Article  Google Scholar 

  24. 24.

    Holsinger T, Steffens D, Phillips C, Helms M, Havlik R, Breitner J. Head injury in early adulthood and the lifetime risk of depression. Arch Gen Psychiatry. 2002;59(1):17–22.

    Article  PubMed  Google Scholar 

  25. 25.

    Guskiewicz KM, Marshall SW, Bailes J, McCrea M, Harding HP, Matthews A, et al. Recurrent concussion and risk of depression in retired professional football players. Med Sci Sport Exer. 2007;39(6):903–9.

    Article  Google Scholar 

  26. 26.

    Lehman E, Hein M, Baron S, Gersic C. Neurodegenerative causes of death among retired National Football League players. Neurology. 2012;79(19):1970–4.

    Article  PubMed  PubMed Central  Google Scholar 

  27. 27.

    Casson IR, Siegel O, Sham R, Campbell EA, Tarlau M, DiDomenico A. Brain damage in modern boxers. JAMA. 1984;251(20):2663–7.

    CAS  Article  PubMed  Google Scholar 

  28. 28.

    Gronwall D, Wrightson P. Delayed recovery of intellectual function after minor head injury. Lancet. 1974;304(7881):605–9.

    Article  Google Scholar 

  29. 29.

    Rabadi M, Jordan B. The cumulative effect of repetitive concussion in sports. Clin J Sports Med. 2001;11(3):194–8.

    CAS  Article  Google Scholar 

  30. 30.

    Austin D, Gabbett T, Jenkins D. Tackling in professional rugby league. J Strength Cond Res. 2011;25(6):1659–63.

    Article  PubMed  Google Scholar 

  31. 31.

    Dretsch MN, Silverberg ND, Iverson GL. Multiple past concussions are associated with ongoing post-concussive symptoms but not cognitive impairment in active-duty army soldiers. J Neurotrauma. 2015;32(17):1301–6.

    Article  PubMed  Google Scholar 

  32. 32.

    Arciniegas DB, Anderson CA, Topkoff J, McAllister TW. Mild traumatic brain injury: a neuropsychiatric approach to diagnosis, evaluation, and treatment. Neuropsychiatr Dis Treat. 2005;1:311–27.

    PubMed  PubMed Central  Google Scholar 

  33. 33.

    Fleminger S, Ponsford J. Long term outcome after traumatic brain injury. Br Med J. 2005;331:1419–20.

    Article  Google Scholar 

  34. 34.

    Decq P, Gault N, Blandeau M, Kerdraon T, Berkal M, ElHelou A, et al. Long-term consequences of recurrent sports concussion. Acta Neurochir (Wien). 2016;158(2):289–300.

    Article  Google Scholar 

  35. 35.

    De Beaumont L, Brisson B, Lassonde M, Jolicoeur P. Long-term electrophysiological changes in athletes with a history of multiple concussions. Brain Inj. 2007;21:631–44.

    Article  PubMed  Google Scholar 

  36. 36.

    De Beaumont L, Lassonde M, Leclerc S, Théoret H. Long-term and cumulative effects of sports concussion on motor cortex inhibition. Neurosurgery. 2007;61(2):329–36.

    Article  PubMed  Google Scholar 

  37. 37.

    De Beaumont L, Theoret H, Mongeon D, Messier J, Leclerc S, Tremblay S, et al. Brain function decline in healthy retired athletes who sustained their last sports concussion in early adulthood. Brain. 2009;132(Pt 3):695–708.

    Article  PubMed  Google Scholar 

  38. 38.

    Dean PJA, Steer A. Long-term effects of mild traumatic brain injury on cognitive performance. Front Hum Neurosci. 2013;7:30.

    Article  PubMed  PubMed Central  Google Scholar 

  39. 39.

    McCrory P, Meeuwisse WH, Kutcher JS, Jordan BD, Gardner A. What is the evidence for chronic concussion-related changes in retired athletes: behavioural, pathological and clinical outcomes? Br J Sports Med. 2013;47:327–30.

    Article  PubMed  Google Scholar 

  40. 40.

    Alexander DG, Shuttleworth-Edwards AB, Kidd M, Malcolm CM. Mild traumatic brain injuries in early adolescent rugby players: long-term neurocognitive and academic outcomes. Brain Inj. 2015;29(9):1113–25.

    CAS  Article  PubMed  Google Scholar 

  41. 41.

    Shuttleworth-Edwards AB, Radloff SE. Compromised visuomotor processing speed in players of Rugby Union from school through to the national adult level. Arch Clin Neuropsychol. 2008;23(5):511–20.

    Article  Google Scholar 

  42. 42.

    Guskiewicz KM, Marshall SW, Bailes J, McCrea M, Cantu RC, Randolph C, et al. Association between recurrent concussion and late-life cognitive impairment in retired professional football players. Neurosurgery. 2005;57(4):719–26.

    Article  PubMed  Google Scholar 

  43. 43.

    Statistics New Zealand. Statistics New Zealand census data. Wellington. Statistics New Zealand. 2006. http://www.stats.govt.nz/Census/about-2006-census/information-by-variable/cigarette-smoking-behaviour.aspx. Accessed 15 Dec 2014.

  44. 44.

    Kerr ZY, Mihalik JP, Guskiewicz KM, Rosamond WD, Evenson KR, Marshall SW. Agreement between athlete-recalled and clinically documented concussion histories in former collegiate athletes. Am J Sport Med. 2015;43(3):606–13.

    Article  Google Scholar 

  45. 45.

    Kerr Z, Marshall S, Guskiewicz K. Reliability of concussion history in former professional football players. Med Sci Sport Exerc. 2012;44(3):377–82.

    Article  Google Scholar 

  46. 46.

    Kerr Z, Marshall S, Harding HJ, Guskiewicz K. Nine-year risk of depression diagnosis increases with increasing self-reported concussions in retired professional football players. Am J Sport Med. 2012;40(10):2206–12.

    Article  Google Scholar 

  47. 47.

    Arnaiz E, Almkvist O, Ivnik RJ, Tangalos EG, Wahlund LO, Winblad B, et al. Mild cognitive impairment: a cross-national comparison. J Neurol Neurosurg Psychiatry. 2004;75(9):1275–80.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  48. 48.

    Bruscoli M, Lovestone S. Is MCI really just early dementia? A systematic review of conversion studies. Int Psychogeriatr. 2004;16(2):129–40.

    Article  PubMed  Google Scholar 

  49. 49.

    Quarrie KM, Gianotti S, Hopkins WG, Hume PA. Effect of nationwide injury prevention programme on serious spinal injuries in New Zealand rugby union. Br Med J. 2007;334:1150–3.

    Article  Google Scholar 

  50. 50.

    King DA, Hume PA, Brughelli M, Gissane C. Instrumented mouthguard acceleration analyses for head impacts in amateur rugby union players over a season of matches. Am J Sports Med. 2015;43(3):614–24.

    Article  PubMed  Google Scholar 

  51. 51.

    King DA, Hume PA, Gissane C, Clark T. Similar head impact acceleration measured using instrumented ear patches in a junior rugby union team during matches in comparison with other sports. J Neurosurg Pediatr. 2016;18(1):65–72.

    Article  PubMed  Google Scholar 

  52. 52.

    King D, Brughelli M, Hume PA, Gissane C. Concussions in amateur rugby union identified with the use of a rapid visual screening tool. J Neurol Sci. 2013;326(1–2):59–63.

    Article  PubMed  Google Scholar 

  53. 53.

    King D, Gissane C, Hume PA, Flaws M. The King-Devick test was useful in management of concussion in amateur rugby union and rugby league in New Zealand. J Neurol Sci. 2015;351(1–2):58–64.

    CAS  Article  PubMed  Google Scholar 

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We thank Dr Martin Raftery (World Rugby/International Rugby Board [IRB]) for initiating the IRB/New Zealand Rugby/Auckland University of Technology (IRB/NZR/AUT) RugbyHealth project and for providing feedback on the technical report that formed the basis of this article. Thanks to Peter Griffiths and Serene Lorimer who provided research administration for the project, Dr Ian Murphy (New Zealand Rugby), Heath Mills (New Zealand Rugby Players Association) and Rob Nichol (New Zealand Cricket Players Association) who endorsed the project and helped with promotion of the study and recruitment of players. We also gratefully recognise the support of Alan Boyd, Chief Executive Officer (CEO) of CNS-VS, for his support and for providing advice on the analysis and interpretation of the data.


Professor Patria Hume collaborated in designing the overarching IRB/NZR/AUT RugbyHealth project, was responsible for the original conception of the study, wrote the funding application, obtained ethical approval, helped recruit participants, helped with analyses of data, provided interpretation of the results, and co-authored the manuscript. Dr Alice Theadom determined the assessment protocols, helped recruit participants, provided interpretation of the results, and co-authored the manuscript. Associate Professor Gwyn Lewis helped recruit participants, helped with analyses of data, provided interpretation of the results, and co-authored the manuscript. Dr Ken Quarrie (New Zealand Rugby) initiated the IRB/NZR/AUT RugbyHealth project, analysed the data, provided interpretation of the results, and co-authored the manuscript. Scott Brown provided liaison for participants for the study, helped recruit participants, and co-authored the manuscript. Dr Rosamund Hill provided clinical interpretation advice and co-authored the manuscript. Professor Stephen Marshall provided statistical advice and co-authored the manuscript.

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Corresponding author

Correspondence to Patria A. Hume.

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The study was funded by World Rugby (IRB), the Sport Performance Research Institute New Zealand (SPRINZ), the National Institute for Stroke and Applied Neurosciences (NISAN), and the Health and Rehabilitation Research Institute (HRRI) of AUT, and NZR.

Competing interests

Kenneth L. Quarrie was employed by NZR prior to and throughout the duration of the project. World Rugby and NZR provided funding for the project. Patria A. Hume, Alice Theadom, Gwyn N. Lewis, Scott R. Brown, Rosamund Hill and Stephen W. Marshall declare that they have no conflicts of interest.

Ethical approval

The study was performed in accordance with the ethical standards of the Declaration of Helsinki, given ethics approval was obtained from the AUT Ethics Committee (AUTEC #12/252). Participants provided informed consent after reading a participant information sheet about the project.

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This article is part of the Topical Collection on Rugby Health.

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Hume, P.A., Theadom, A., Lewis, G.N. et al. A Comparison of Cognitive Function in Former Rugby Union Players Compared with Former Non-Contact-Sport Players and the Impact of Concussion History. Sports Med 47, 1209–1220 (2017). https://doi.org/10.1007/s40279-016-0608-8

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  • Executive Functioning
  • Cognitive Flexibility
  • Mild Traumatic Brain Injury
  • Rugby Player
  • Rugby Union