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The Pupillary Light Reflex as a Biomarker of Concussion.

Published version
Peer-reviewed

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Authors

Carrick, Frederick Robert  ORCID logo  https://orcid.org/0000-0002-2818-6551
Azzolino, Sergio F 
Hunfalvay, Melissa 
Pagnacco, Guido 
Oggero, Elena 

Abstract

The size of our pupils changes continuously in response to variations in ambient light levels, a process known as the pupillary light reflex (PLR). The PLR is not a simple reflex as its function is modulated by cognitive brain function and any long-term changes in brain function secondary to injury should cause a change in the parameters of the PLR. We performed a retrospective clinical review of the PLR of our patients using the BrightLamp Reflex iPhone app. The PLR variables of latency, maximum pupil diameter (MaxPD), minimum pupil diameter (MinPD), maximum constriction velocity (MCV), and the 75% recovery time (75% PRT) were associated with significant differences between subjects who had suffered a concussion and those that had not. There were also significant differences in PLR metrics over the life span and between genders and those subjects with and without symptoms. The differences in PLR metrics are modulated not only by concussion history but also by gender and whether or not the person has symptoms associated with a head injury. A concussive injury to the brain is associated with changes in the PLR that persist over the life span, representing biomarkers that might be used in clinical diagnosis, treatment, and decision making.

Description

Keywords

pupil light reflex, concussion, gender difference, brain function, pupillometry

Journal Title

Life (Basel)

Conference Name

Journal ISSN

2075-1729
2075-1729

Volume Title

11

Publisher

MDPI AG