Table 3

Assessments of risk of bias in included studies, according to the NOS

Author, dateRepresentativeness of exposed cohorts†Selection of nonexposed cohort‡Ascertainment of exposure§Demonstration outcome of interest not present study start¶Comparability of cohorts: assessment tool‡Comparability of cohorts: other factors‡Assessment of outcomeFollow-up long enough for outcomes to occur**Adequacy of follow-up of cohorts**Potential maximum scoreActual score
Studies providing complete preconcussion or preconcussion and postconcussion data
Benedict, 20150***N/AN/A43
Glaviano, 20150***N/AN/A43
Hänninen, 2015****N/AN/A44
Jinguji, 20120***N/AN/A43
Mayfield, 2013******66
Putukian, 20150*****65
Snyder, 2014****N/AN/A44
Valovich McLeod, 2012****N/AN/A44
Weber, 2013****N/AN/A44
Zimmer, 2015****N/AN/A44
Studies presenting partial data
Baker, 20150*00N/AN/A41
Carson, 20140*0*0062
Echlin, 20100*****65
Galetta, 20130*00*062
Galetta, 2015**0***65
Jennings, 2015***0N/AN/A43
King, 20120*****65
King, 20130*****65
King, 20150*0*N/AN/A42
Miller, 20150***N/AN/A43
Mrazik, 20130***N/AN/A43
  • N/A=study performed a baseline assessment and planned no follow-up SCAT assessment, or follow-up data are not related to concussion (Jennings et al37 compared preseason to postseason SAC and BESS scores, Mrazik et al47 compared players before and after the 20 m Leger shuttle-run test and Weber (2013) compared wrestlers at baseline to postpractice when they were dehydrated).

  • †Is the exposed (preteenaged to high school population with active sports participation assessed with SCAT2 or SCAT3 tools) cohort truly or somewhat representative of young athletes who suffer sports-related concussions/are exposed to sports-related concussions?

  • ‡Because this review identified no studies with interventions, none included a hemi-cohort exposed to an intervention and a hemi-cohort which was the control.

  • §Exposure is defined as a competitive athlete who has received a complete or partial SCAT2 or SCAT3 assessment.

  • ¶Players were specifically asked if they had a recent concussion before the SCAT was administered; or if they were in a concussed group whether they also had a more recent concussion before testing.

  • ** Single asterisk=complete follow-up, OR if participants lost to follow-up were unlikely to introduce bias (according to NOS instructions).

  • BESS, Balance Error Scoring System; NOS, Newcastle-Ottawa Scale; SAC, Standardised Assessment of Concussion; SCAT, Sport Concussion Assessment Tool; SCAT, Sport Concussion Assessment Tool.