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

• Published in: Sports medicine (Auckland) Vol. 47; no. 6; pp. 1209 - 1220
• Main Authors: Hume, Patria A., Theadom, Alice, Lewis, Gwyn N., Quarrie, Kenneth L., Brown, Scott R., Hill, Rosamund, Marshall, Stephen W.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.06.2017; Springer Nature B.V
• Subjects: Adult; Athletes; Athletic Injuries; Attention; Brain Concussion - diagnosis; Brain Concussion - psychology; Censuses; Central nervous system; Cognition; Cognition - physiology; Cognition Disorders - diagnosis; Cognitive ability; Concussion; Cross-Sectional Studies; Demographics; Executive function; Flexibility; Football - injuries; Group dynamics; Humans; Information processing; Internet; Medicine; Medicine & Public Health; Memory; Middle Aged; Motor task performance; Neuropsychological Tests; Neurosurgery; New Zealand; Original Research Article; Reaction time task; Rugby; Rugby Health; Sports injuries; Sports Medicine; Sports related injuries; Traumatic brain injury; Vital signs; Vital statistics; New Zealand; United States > US; Cognitive Flexibility; Rugby Player; Mild Traumatic Brain Injury; Executive Functioning; Rugby Union
• ISSN: 0112-1642; 1179-2035
• DOI: 10.1007/s40279-016-0608-8

Aim 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. Methods 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. Results 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. Conclusions 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.