IS NEAR POINT OF CONVERGENCE ASSOCIATED WITH SYMPTOM PROFILES OR RECOVERY IN ADOLESCENTS AFTER CONCUSSION?

Abstract

Background:Visual impairments, including oculomotor impairments, are common following concussion. Accurate, efficient, and objective measurement of post-concussion visual impairments may help guide treatment pathways. Less is known about how specific concussion symptoms are associated with visual impairments.Hypothesis/Purpose:Our purpose was to compare the clinical and injury characteristics of concussion patients who demonstrated receded near point of convergence (NPC) (defined as measurement >6 cm using accommodation rule from bridge of nose) to those with normal NPC (≤6 cm). We hypothesize that patients demonstrating receded NPC would show greater symptom burden and have longer recovery when compared to those with normal NPC.Methods:Concussion patients who were seen within 14 days of injury were included. We performed univariable demographic, injury, and clinical characteristic comparisons between those with and without receded NPC break point using independent samples t-tests and Chi-square analyses. We compared NPC break point between those who did not recover within 28 days of injury (PPCS; persistent post-concussion symptoms) and those who did (no PPCS). A multivariable linear regression model was constructed to identify which factors were associated with NPC break point distance.Results:We evaluated 123 patients using a multimodal concussion evaluation within 14 days of injury. Those with receded NPC (n=77) were significantly younger than those with normal NPC (n=46; Table 1). The receded NPC group had a significantly greater proportion of patients reporting headaches at initial assessment, as well as significantly greater overall, cognitive and somatic symptom severity (Table 2). The group who went onto experience PPCS had a significantly greater NPC at initial evaluation than those without PPCS (p=0.02; Figure 1). The receded NPC group committed more modified Balance Error Scoring System (mBESS) errors than the normal NPC group, but there were no significant differences for tandem gait test performance (Table 3). In our multivariable model, we observed that among all potential predictor variables, more severe somatic symptoms were significantly associated with a greater NPC (Table 4).Conclusion:Those with receded NPC at initial evaluation showed an increased symptom burden, most notable with somatic symptoms, compared with those without receded NPC. Additionally, we were able to elucidate that those who went on to develop PPCS had greater NPC than those recovered within 28 days. Visual disorders may be an important driver of symptom profiles following concussion in adolescents. The impact of visual disturbance treatment following concussion in adolescents on symptom resolution should be further evaluated.Tables/Figure:Figure 1.Individual data points describing the distribution of NPC break points (cm) between patients who required >28 days for concussion symptom resolution (PPCS) and those who recovered within 28 days (No PPCS). The black bar represents the mean group value. The PPCS group had a significantly greater mean NPC break point than the No PPCS group (p=0.02).