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Concussed athletes walk slower than non-concussed athletes during cognitive-motor dual-task assessments but not during single-task assessments 2 months after sports concussion: a systematic review and meta-analysis using individual participant data
  1. Fionn Büttner1,
  2. David R Howell2,3,4,
  3. Clare L Ardern5,6,
  4. Cailbhe Doherty1,7,
  5. Catherine Blake1,
  6. John Ryan8,
  7. Robert Catena9,
  8. Li-Shan Chou10,
  9. Peter Fino11,
  10. Coralie Rochefort12,
  11. Heidi Sveistrup12,13,
  12. Tonya Parker14,
  13. Eamonn Delahunt1,15
  1. 1 School of Public Health, Physiotherapy, and Sports Science, University College Dublin, Dublin, Ireland
  2. 2 Sports Medicine Center, Children's Hospital Colorado, Aurora, CO, United States
  3. 3 Department of Orthopedics, University of Colorado School of Medicine, Aurora, CO, United States
  4. 4 The Micheli Center for Sports Injury Prevention, Waltham, CO, United States
  5. 5 Sport and Exercise Medicine Research Centre, La Trobe University, Bundoora, Victoria, Australia
  6. 6 Department of Medicine and Health Sciences, Division of Physiotherapy, Linköping, Sweden
  7. 7 Insight Centre for Data Analytics, UCD, Dublin 4, Dublin, Ireland
  8. 8 Emergency Department, St. Vincent's University Hospital, Elm Park, Dublin 4, Dublin, Ireland
  9. 9 College of Education, Washington State University, Pullman, WA, USA
  10. 10 Department of Human Physiology, University of Oregon, Eugene, OR, USA
  11. 11 College of Health, University of Utah, Salt Lake City, UT, USA
  12. 12 School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada
  13. 13 Faculty of Health Sciences, University of Ottawa, Ottawa, ON, Canada
  14. 14 Department of Movement Science, Grand Valley State University, Allendale, MI, USA
  15. 15 Institute for Sport & Health, University College Dublin, Dublin, Ireland
  1. Correspondence to Fionn Büttner, School of Public Health, Physiotherapy, and Sports Science, University College Dublin, Dublin 4, Dublin, Ireland; fionn.cleirigh-buttner{at}


Objectives To determine whether individuals who sustained a sports concussion would exhibit persistent impairments in gait and quiet standing compared to non-injured controls during a dual-task assessment .

Design Systematic review and meta-analysis using individual participant data (IPD).

Data sources The search strategy was applied across seven electronic bibliographic and grey literature databases: MEDLINE, EMBASE, CINAHL, SportDISCUS, PsycINFO, PsycARTICLES and Web of Science, from database inception until June 2017.

Eligibility criteria for study selection Studies were included if; individuals with a sports concussion and non-injured controls were included as participants; a steady-state walking or static postural balance task was used as the primary motor task; dual-task performance was assessed with the addition of a secondary cognitive task; spatiotemporal, kinematic or kinetic outcome variables were reported, and; included studies comprised an observational study design with case–control matching.

Data extraction and synthesis Our review is reported in line with the Preferred Reporting Items for Systematic review and Meta-Analyses-IPD Statement. We implemented the Risk of Bias Assessment tool for Non-randomised Studies to undertake an outcome-level risk of bias assessment using a domain-based tool. Study-level data were synthesised in one of three tiers depending on the availability and quality of data: (1) homogeneous IPD; (2) heterogeneous IPD and (3) aggregate data for inclusion in a descriptive synthesis. IPD were aggregated using a ‘one-stage’, random-effects model.

Results 26 studies were included. IPD were available for 20 included studies. Consistently high and unclear risk of bias was identified for selection, detection, attrition, and reporting biases across studies. Individuals with a recent sports concussion walked with slower average walking speed (χ2=51.7; df=4; p<0.001; mean difference=0.06 m/s; 95% CI: 0.004 to 0.11) and greater frontal plane centre of mass displacement (χ2=10.3; df=4; p=0.036; mean difference −0.0039 m; 95% CI: −0.0075 to −0.0004) than controls when evaluated using a dual-task assessment up to 2 months following concussion.

Summary/conclusions Our IPD evidence synthesis identifies that, when evaluated using a dual-task assessment, individuals who had incurred a sports concussion exhibited impairments in gait that persisted beyond reported standard clinical recovery timelines of 7–10 days. Dual-task assessment (with motion capture) may be a useful clinical assessment to evaluate recovery after sports concussion.

Protocol pre-registration This systematic review was prospectively registered in PROSPERO CRD42017064861.

  • concussion
  • gait
  • balance
  • review
  • individual patient data

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  • Contributors FCB conceived the present idea articulated in this manuscript and initiated the IPD meta-analytic process. FCB and CLA developed, edited, and reviewed the pre-specified review protocol and risk of bias assessment criteria. FCB and ED formulated the review search strategy, screened subsequent search results for inclusion, abstracted aggregate data, and completed risk of bias assessments of included studies. FCB and DRH contacted 'contributing authors' to request the provision of IPD. FCB, DRH, and CD performed re-analyses of within-study IPD. FCB and CB statistically harmonised, re-checked, and analysed IPD. DRH, RDC, LC, PF, CR, HS and TP contributed IPD for harmonisation, re-checking, and analysis. FCB composed the first draft of this manuscript. FCB, DRH, CLA, CD, CB, JR, and ED contributed towards the composition and revision of subsequent manuscript drafts. All co-authors edited and approved the final manuscript.

  • Funding Fionn Cléirigh Büttner is the recipient of an Irish Research Council Government of Ireland Post-graduate Scholarship (Award ID: GOIPG/2016/87).

  • Competing interests CLA and ED are editorial board members of the British Journal of Sports Medicine.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.