McMillan TM et al, 201732
| Cross-sectional with external comparison group (‘population’ controls) |
Self-reported Definition of concussion: a blow or injury to your head where you may or may not have lost consciousness and then had symptoms such as dizziness, blurred vision, nausea, vomiting, headache, poor concentration. It might be that symptoms were not noticeable straight away but you may have noticed them later or have had ‘gaps’ in your memory for the game that were unusual or you might have remembered little at all about the game
Prevalence of concussion among retired international rugby players: 92%
Mean (SD) number of concussions: 13.9 (18.9) |
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Prevalence of cognitive impairment defined as M0CA<26: 9/52 (17%) |
No differences in terms of cognition, among players, according to the number of concussions (no repeat concussion, 0–1; moderate, 2–9 and high 10+)
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Hume et al, 201731
| Cross-sectional with between sports (community rugby players and non-contact sportspeople) and external comparison group (US norms) |
Self-reported by online questionnaire Definition of concussion: ‘Concussion was defined as being a blow to the head followed by a variety of symptoms (loss of consciousness, headache, dizziness, loss of balance, blurred vision, ‘seeing stars’, feeling in a fog or slowed down, memory problems, poor concentration, nausea or throwing up)”
Elite rugby players: Prevalence of concussion: 85%
Mean concussions: 3.5±2.0
Community rugby players: Prevalence of concussion: 77%
Mean concussions: 2.9±2.2
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Former players (including elite rugby, community rugby and non-contact sports) who recalled one or more concussions had worse scores on cognitive flexibility, executive functioning, and complex attention than players who did not recall experiencing a concussion
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The elite-rugby group performed worse on tests of complex attention, processing speed, executive functioning, and cognitive flexibility than the non-contact sport group, and worse than the community-rugby group on complex attention
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Compared with US norms, all three former player groups performed worse on verbal memory and reaction time; rugby groups performed worse on complex attention, processing speed, cognitive flexibility and executive functioning Elite rugby group performed better in relation to motor speed than US norms
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Decq et al. 201627
| Cross-sectional with a between sports comparison group (high-level retired sportspeople) |
Prevalence of concussion among rugby players: 77%
Mean concussions: 3.1 (SD 5.0)
Median concussions: 2 (IQR 1–3)
Mean concussions with loss of consciousness: 1.5 (2.7)
Mean concussions with loss of memory: 0.9 (SD 1.3) |
Cognitive function assessed by TICSm
37
Depressive disorders (PHQ-9 score) Fluency disorders (Isaacs Set Test) Headache severity (HIT-6 score)
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Prevalence of cognitive impairment defined as TICS-m ≤30: 57%
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Mild cognitive disorder (TICS ≤30) prevalence: 57% among rugby players and 40% among other sports (univariate p=0.005) Mean TICS score 30. (SD 3.5) among rugby players and 31.3 (3.6) among other sports (univariate p=0.007)
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