Table 2

Concussion assessment and outcome measurements among ice hockey players in the included studies

Ref.Study designMethod of assessing concussion and its definitionMeasurement of outcome (s)Prevalence of outcomeInternal comparisonBetween sport comparisonExternal comparisons
Esopenko C et al 201828 Cross-sectional study with external comparison group (‘community’ controls)

  • Self-reported concussion history (only concussions reported from ≥15 years of age were included in the analyses)

  • Concussion was defined as a blow to the head followed by clinical symptoms, including altered consciousness, confusion, dizziness, headache, fogginess, memory problems and sensitivity to light or sound

Mean (SD) concussion among hockey players: 4.8 (2.7)
Median (IQR) number of concussion among hockey players: 5.0 (3.0)

  • Neurocognitive tests

  • Psychiatric disorders

  • Neurological examination

N/A (principle component analysis used)

  • Executive/intellectual functioning from the neuropsychological battery was significantly associated with the number of concussions after accounting for variance due to age

  • Former players performed worse on the executive/intellectual function, relative to comparison participants

Baker JG, et al 201824 Cross-sectional study with between sports comparison group (non-contact master athletes)

  • Information on concussion not collected because deemed to be too inaccurate

  • Neurocognitive tests

  • Cognitive impairment as defined by Jak and coll.38

  • Depression

  • Vascular risk factors

 Prevalence of cognitive impairment as defined by Jak and coll.38 among contact sport athletes: 38%

  • The contact sport athletes scored significantly lower on this measure of estimated IQ, but did not significantly differ from non-contact sport athletes on most of the primary scores in the five domains (executive function, attention, memory, language, perceptual motor skills). They only performed worse in letter fluency and immediate recall

  • Eight contact sport athletes (38%) versus three non-contact controls (14%) met the criteria for MCI

  • MCI, mild cognitive impairment.