Comparing Postconcussion Sway Balance and Cognitive Test Performance With Preinjury Baseline Identifies a Higher Percentage of Impaired Concussed Athletes Than Comparison With Normative Values
Orthopaedic journal of sports medicine · 2026
Comparing Sway concussion scores to an athlete's own baseline (not just norms) catches more true concussions—but only if you require impairment on 2+ modules, and even then it misses many cases.
The paper
Cohort study (Level 3 evidence), athletes with baseline Sway Sports+ testing 1 year apart, compared postconcussion (within 3 days) scores against individual baseline vs normative reference data; sample size not stated in the abstract.
What they found
Using a single-module impairment threshold, both methods flagged most concussed athletes as impaired (e.g., 95% via baseline vs 89% via norms at the 70% CI), but single-module 'impairment' was also common in non-concussed controls. Requiring impairment on ≥2 modules, baseline comparison outperformed normative comparison at every CI threshold (e.g., 82% vs 68% at 70% CI; 67% vs 58% at 80% CI; 52% vs 47% at 90% CI), and ≥2-module impairment was rare in controls but frequent in concussed athletes.
The appraisal
The ≥2-module criterion is the clinically relevant finding since it addresses false-positive impairment seen with single-module thresholds, but sensitivity drops sharply as CI stringency increases (from 82% down to 52% for baseline comparison), meaning roughly half of concussed athletes are missed at the 90% CI even with the better method. No blinding is reported, no power calculation is described, and the abstract omits sample size, age/sport mix, and how many athletes had 1-year-apart baselines available (a practical barrier this design itself highlights) — all of which limits confidence in generalizability.
The gap
Specificity (false-positive rate in true non-concussed controls) and a head-to-head statistical comparison (e.g., McNemar's test, CIs around the percentage differences) are not reported, so it's unclear whether the baseline-vs-normative gap is robust or just a point estimate from a small/unspecified sample.
Landmark context
This extends the established literature on individualized baseline testing improving concussion detection over population norms (a rationale long used to justify programs like ImPACT and other baseline neurocognitive testing), applying that same logic specifically to the newer Sway Medical balance/cognitive platform rather than to legacy tools.
What to do Monday
For clinics using Sway Sports+, this supports continuing to obtain individual baselines and applying a ≥2-module impairment rule rather than flagging on any single abnormal module or relying solely on normative cutoffs — but clinicians should not treat a single-module flag as diagnostic, and should recognize that even the better method misses roughly a third to half of concussed athletes depending on CI threshold chosen.
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