Objectives: Objective measures to diagnose and to monitor improvement of symptoms following mild traumatic brain injury (mTBI) are lacking. Computerized eye tracking has been advocated as a rapid, user friendly, and field-ready technique to meet this need.
Design: Eye-tracking data collected via a head-mounted, video-based binocular eye tracker was used to examine saccades, fixations, and smooth pursuit movement in military Service Members with postconcussive syndrome (PCS) and asymptomatic control subjects in an effort to determine if eye movement differences could be found and quantified.
Participants: Sixty Military Service Members with PCS and 26 asymptomatic controls.
Outcome Measures: The diagnosis of mTBI was confirmed by the study physiatrist's history, physical examination, and a review of any medical records. Various features of saccades, fixation and smooth pursuit eye movements were analyzed.
Results: Subjects with symptomatic mTBI had statistically larger position errors, smaller saccadic amplitudes, smaller predicted peak velocities, smaller peak accelerations, and longer durations. Subjects with symptomatic mTBI were also less likely to follow a target movement (less primary saccades). In general, symptomatic mTBI tracked the stepwise moving targets less accurately, revealing possible brain dysfunction.
Conclusions: A reliable, standardized protocol that appears to differentiate mTBI from normals was developed for use in future research. This investigation represents a step toward objective identification of those with PCS. Future studies focused on increasing the specificity of eye movement differences in those with PCS are needed.
Departments of Physical Medicine and Rehabilitation (Drs Cifu and Carne) and Biomedical Engineering (Drs Wetzel and Gitchel), Virginia Commonwealth University; Physical Medicine and Rehabilitation Program Office of the Department of Veterans Affairs (Dr Cifu); and Department of Mathematics and Computer Science, University of Richmond (Drs Wares and Hoke), Richmond, Virginia.
Corresponding Author: William Carne, PhD, Department of PM&R, Virginia Commonwealth University, 1223 East Marshall Street, Richmond, VA 23298 (firstname.lastname@example.org).
Funding was provided for the primary study by a Defense Advanced Research Projects Agency grant (N66001-09-2-206), US Navy Bureau of Medicine and Surgery for contract funding temporary duty requirements, and the US Army Medical Materiel Development Activity for end-of-study contract funding. The funding sources had no role in the study design, analysis, interpretation of the data, the writing of the paper, or the decision to submit the paper for publication.
The views expressed herein do not necessarily represent the views of the Department of Veterans Affairs, Department of Defense, or the US Government.
The authors declare no conflicts of interest.