Near point of convergence in high school athletes

Abstract

Context: Awareness of sport-related concussions (SRC) has increased significantly in recent years. The clinical diagnosis of SRC is typically performed with tools assessing postural stability, cognitive function, neurocognitive, vestibular, and ocular motor deficits. Recent evidence has indicated convergence dysfunction to be a complication following SRC. Near point of convergence (NPC) has been reported to be a useful assessment of convergence deficits following SRC. No investigation on differences in NPC values between different instrument methods has been performed. Objective: The primary purpose of this study was to determine if instrument method (tongue depressor or accommodative ruler) influences NPC values in high school athletes. The secondary purpose was to assess whether a difference exists in NPC values between contact and limited or non-contact sport type athletes. Design: Quasi-experimental, ex post facto. Setting: High School. Patients or Other Participants: 201 high school student-athletes (age = 15.7±1.2 yrs, height = 170.5±10.0 cm, mass = 69.9±16.2 kg) from 14 sports were assessed for NPC values. Main Outcome Measures: Near point of convergence values with tongue depressor (NPC-TD) and accommodative ruler (NPCAR) instrumentation. Results: There was a significant difference between NPC-TD (2.0±2.8cm) and NPC-AR (2.8±2.7cm) values, t(200)=5.85, p<0.001. There was a significant difference between contact and limited/non-contact groups with NPC-TD, t(199)=4.01, p<0.001, and NPC-AR, t(199)=2.71, p=0.004. Conclusions: Instrumentation and procedures affect NPC values in a high school student-athlete population. These data indicate the importance of consistent collection methods when utilizing NPC to assess convergence deficits following SRC.