Abstract
Purpose :
The diagnostic and prognostic importance of pupil findings in severe traumatic brain injury is well established. Objective pupillometry has been proposed as a potential screening tool for mild traumatic brain injury/concussion. The purpose of this study was to evaluate the repeatability of objective pupillometry in the setting of mass preseason sports physicals for middle school and high school athletes. Exploratory analyses were conducted evaluating the association of athlete-reported concussion to the measured pupil function.
Methods :
In Alabama all middle school and high school athletes are required to have preseason physicals to be cleared for school related sports play. 786 athletes aged 11-19 from 14 area schools participated in screening associated with the Children’s Hospital of Alabama. As part of the vision screening assessment battery, objective pupillometry was done in each eye using the NeurOptics (NPI-200®) infrared pupillometer. The NPI-200 generates a proprietary summary value of pupil function the NPi, values less than 3 suggested by the manufacturer to be abnormal. As part of the screening pupillometery measurements were made twice in each eye. Intraclass correlation coefficients and limits of agreement between repeated measures were developed. General linear model or chi square was used to assess association with concussion.
Results :
The mean NPi values for the two measures of right and left pupils were almost identical at 4.1(sd 0.4, n=639). The mean differences between first and second testing was near 0 for each eye (sd .27, OD, 0.26 OS). The mean absolute difference between the first and second measure was 0.2 (sd 0.2). Intraclass correlation coefficient was good to excellent at 0.78 for both pupils. The calculated 95% limits of agreement for NPi on an individual eye were ±.75 OD, ±0.72 OS. The mean absolute difference in NPi between pupils was .17(sd.16, range 0 to 1.70).No association was found between Npi less than 3 in either eye and history of concussion(p=.34). No association was found between mean absolute difference in NPi value between the eyes and concussion history(p=.74).
Conclusions :
The NPi shows relatively good to excellent repeatability in the setting of mass screening, Within this population NPi differences greater than or less than .75 units are indicative of change beyond measurement repeatability. No association between history of concussion and NPi value was found.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.