Despite the current use of brain imaging and neurocognitive assessment, the optimal diagnosis and treatment of concussive injuries have long been hampered by a lack of objective testing. That might soon change, as researchers have identified a group of oculomotor, vestibular, and reaction time (OVRT) metrics associated with both acute and chronic concussion.1
Testing protocol. Drawing on 50 high school–aged athletes clinically diagnosed with a sports-related concussion and 170 control students, the study team used a video nystagmography device that combines eye tracking, stimulation, and analysis to assess OVRT function.
Tests were conducted in dim light with the students seated in front of a white reflective screen over a broad range of postconcussion times, from 1 day to 1 year after injury. Full-field stimuli were created by a rotating projector. Other visual stimuli were projected by a 650-nm laser onto the display surface.
A potential biomarker. “We found multiple deficits in the concussion population compared with the controls,” said Kevin M. Kelly, MD, PhD, a neurologist at Allegheny General Hospital in Pittsburgh. “These included alterations in smooth pursuit tracking, delays in smooth pursuit initiation, delayed reaction times, and dramatically impaired response during optokinetic nystagmus tests.”
Optokinetic nystagmus (OKN) gain was the only metric that remained significantly impaired more than 3 weeks following injury. This suggests not only that concussions can induce oculomotor deficits beyond the initial phases of recovery, but also that OKN might serve as a potential biomarker of protracted healing from traumatic brain injury.
Therapeutic importance. Because linear regression models were able to distinguish between concussed students and controls with high accuracy, the research team believes that OVRT metrics could serve as a diagnostic aid for general clinical use.
“These results indicate that OVRT tests can be used as a reliable adjunctive tool in the diagnosis of concussion,” said Dr. Kelly. “And given the potential for OVRT measurements to shift over the course of recovery, they might also provide the practitioner with objective assessments regarding the utility and efficacy of therapeutic approaches—such as medications and physical therapy—for treating traumatic brain injury.”
1 Kelly KM et al. J Head Trauma Rehabil. Published online Sept. 18, 2018.
Relevant financial disclosures—Dr. Kelly: U.S. Department of Defense: S; Neuro Kinetics: S.
For full disclosures and the disclosure key, see below.
Full Financial Disclosures
Dr. Chen U.S. Department of Defense: S; Harvard Foundation Grant (Fidelity Charitable Fund): S.
Dr. Drenser Interview Medical Systems: O,P; Phoenix: O; Retinal Solutions: O,P; Spark Therapeutics: C.
Prof. Dua Croma: C; Dompé: C; GlaxoSmithKline: O; NuVision Biotherapeutic: O; Santen: C; Shire: C; Thea: C; VisuFarma: C.
Dr. Kelly U.S. Department of Defense: S; Neuro Kinetics: S.
||Consultant fee, paid advisory boards, or fees for attending a meeting.
||Employed by a commercial company.
||Lecture fees or honoraria, travel fees or reimbursements when speaking at the invitation of a commercial company.
||Equity ownership/stock options in publicly or privately traded firms, excluding mutual funds.
||Patents and/or royalties for intellectual property.
||Grant support or other financial support to the investigator from all sources, including research support from government agencies (e.g., NIH), foundations, device manufacturers, and/or pharmaceutical companies.
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