Zeitschrift für Wirbelsäule

Pupillary Light Reflex as an Objective Biomarker for Early Identification of Blast-Induced mTBI

Abstract

Jose E Capo-Aponte, Thomas G Urosevich, David V Walsh, Leonard A Temme and Aaron K Tarbett

Purpose: There is an increase in mild traumatic brain injury (mTBI) in US Warfighters resulting from exposure to explosive devices. However, there is a lack of objective biomarkers to accurately identify mTBI in order to make a return-to-duty (RTD) determination in the battlefield. The present study examined pupillary light reflex (PLR) as a potential objective biomarker for early identification of mTBI.

Methods: The PLR-200™ monocular infrared pupillometer was used to quantify PLR under mesopic conditions in 20 U.S. military personnel with blast induced-mTBI and 20 age-matched non-TBI military personnel. Eight PLR parameters were assessed: maximum diameter; minimum diameter; percent of constriction; constriction latency; average constriction velocity; maximum constriction velocity; 75% recovery time; average dilation velocity.

Results: Four of the eight PLR parameters were statistically different between the groups: constriction latency, average constriction velocity, dilation velocity, and 75% recovery time.

Conclusions: This study demonstrates the potential application of PLR as an objective index of autonomic nervous system activity and the value of using PLR, in conjunction with other biomarkers, to optimize the diagnosis of mTBI in the battlefield and to facilitate the RTD decisions by deployed healthcare providers.