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. 2021 Mar;10(2):138-144.
doi: 10.1016/j.jshs.2020.10.007. Epub 2020 Oct 28.

Impaired eye tracking is associated with symptom severity but not dynamic postural control in adolescents following concussion

Jessie R Oldham  1 , William P Meehan 3rd  2 , David R Howell  3
Affiliations

Impaired eye tracking is associated with symptom severity but not dynamic postural control in adolescents following concussion

Jessie R Oldham et al. J Sport Health Sci. 2021 Mar.

Abstract

Purpose: The purpose of the study was to (1) examine the relationship between self-reported symptoms and concussion-related eye tracking impairments, and (2) compare gait performance between (a) adolescents with a concussion who have normal eye tracking, (b) adolescents with a concussion who have abnormal eye tracking, and (c) healthy controls.

Methods: A total of 30 concussed participants (age: 14.4 ± 2.2 years, mean ± SD, 50% female) and 30 controls (age: 14.2 ± 2.2 years, 47% female) completed eye tracking and gait assessments. The BOX score is a metric of pupillary disconjugacy, with scores <10 classified as normal and ≥10 abnormal. Symptoms were collected using the Post-Concussion Symptom Scale (PCSS), and gait speed was measured with triaxial inertial measurement units. We conducted a linear regression to examine the relationship between PCSS and BOX scores and a two-way mixed effects analysis of variance to examine the effect of group (abnormal BOX, normal BOX, and healthy control) on single- and dual-task gait speed.

Results: There was a significant association between total PCSS score and BOX score in the concussion group (β = 0.16, p = 0.004, 95% confidence interval (95%CI): 0.06‒0.27), but not in the control group (β = 0.21, p = 0.08, 95%CI: -0.03 to 0.45). There were no significant associations between PCSS symptom profiles and BOX scores in the concussion or control groups. There were also no significant differences in single-task (Abnormal: 1.00 ± 0.14 m/s; Normal: 1.11 ± 0.21 m/s; Healthy: 1.14 ± 0.18 m/s; p = 0.08) or dual-task (Abnormal: 0.77 ± 0.15 m/s; Normal: 0.84 ± 0.21 m/s; Healthy: 0.90 ± 0.18 m/s; p = 0.16) gait speed.

Conclusion: The concussed group with impaired eye tracking reported higher total symptom severity, as well as worse symptom severity across the 5 PCSS symptom domain profiles. However, eye tracking deficits did not appear to be driven by any particular symptom domain. While not statistically significant, the slower gait speeds in those with abnormal BOX scores may still be clinically relevant since gait-related impairments may persist beyond clinical recovery.

Keywords: Gait; Mild traumatic brain injury; Vision.

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Conflict of interest statement

Competing interests WPM III receives royalties from (1) ABC-Clio publishing for the sale of his books, Kids, sports, and concussion: A guide for coaches and parents and concussions, (2) Springer International for the book Head and neck injuries in young athletes, and (3) Wolters Kluwer for working as an author for UpToDate. His research is funded, in part, by philanthropic support from the National Hockey League Alumni Association through the Corey C. Griffin Pro-Am Tournament and the National Football League. DRH receives research support from the Eunice Kennedy Shriver National Institute of Child Health & Human Development (R03HD094560) and the National Institute of Neurological Disorders and Stroke (R01NS100952 and R41NS103698) of the National Institutes of Health. He has previously received research support from a research contract between Boston Children's Hospital, Cincinnati Children's Hospital Medical Center, and ElMindA Ltd., and the Eastern Athletic Trainers Association Inc. JRO has no competing interests to declare. All the support had no involvement in the study design and writing of the manuscript or the decision to submit it for publication.

Figures

Image, graphical abstract
Graphical abstract
Fig 1
Fig. 1
There was a significant association between total PCSS scores and BOX scores in the concussion group (β = 0.16, p = 0.004, 95%CI: 0.06‒0.27) but not in the control group (β = 0.21, p = 0.08, 95%CI: –0.03 to 0.45). CI = confidence interval; PCSS = Post-Concussion Symptom Scale.
Fig 2
Fig. 2
There was not a significant difference for single-task (F = 2.15, p = 0.13) or dual-task (F = 1.66, p = 0.20) gait speed. A Tukey post hoc test revealed no significant differences in single-task gait speed (Abnormal: 1.00 ± 0.14 m/s; Normal: 1.11 ± 0.21 m/s; Healthy: 1.14 ± 0.18 m/s; p = 0.08) or dual-task gait speed (Abnormal: 0.77 ± 0.15 m/s; Normal: 0.84 ± 0.21 m/s; Healthy: 0.90 ± 0.18 m/s; p = 0.16) between the groups. The error bars represent 95% confidence intervals.
See this image and copyright information in PMC

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