Objective To examine differences between youth athletes with concussion and uninjured controls using a smartphone-based motor-cognitive assessment measuring single/dual-task gait velocity and cognitive accuracy across two time points.

Design Case-control study.

Setting Sports medicine center at a regional children’s hospital.

Participants We enrolled twenty-one uninjured controls (15.51.6 years, 48% female) and twenty-seven individuals with concussion (15.41.6 years, 56% female). Participants were 12–18 years of age.

Interventions Both groups completed two assessments, four weeks apart (control mean: 27.30.7 days apart; concussion mean: 27.83.4 days apart). The concussion group completed their initial assessment ≤14 days of concussion (mean=7.33.1 days post-injury). At both initial and follow-up assessments, a smartphone affixed to participants’ lumbar spine acquired and analyzed single/dual-task spatiotemporal gait and cognitive metrics during a 20-meter walking task.

Outcome Measures Primary outcomes included single- and dual-task gait velocity (m/s) and cognitive/Stroop accuracy (%). A linear mixed model was used to compare motor/cognitive outcomes between groups and across timepoints using an adjusted significance level of p<0.0125.

Main Results The concussion group walked significantly faster at the follow-up assessment compared to the initial assessment during single-task (follow-up: 1.000.23 m/s vs. initial: 0.860.13 m/s; p=0.001) and dual-task (follow-up: 1.100.24 m/s vs. initial: 0.920.14 m/s; p=0.011) conditions. Dual-task Stroop accuracy was significantly less accurate among the concussion group than the control group across both time points (main effect of group; p=0.010).

Conclusions The use of a smartphone-based motor-cognitive assessment in adolescents with concussion is a clinically feasible and useful tool to track concussion recovery across time.