To examine the relationship between self-reported post concussion headache severity and convergence insufficiency (CI) a common binocular vision deficit, in a clinical post-concussive population.

Both headache and CI are common sequelae of concussion that have been associated with prolonged recovery. Independent of head injury, CI is a known predictor of headache pain[1]. However, the relationship between CI and headache in a post-concussion population is less clear.  This is an important relationship to explore since headaches are one of the most common and debilitating post-concussive symptoms.

[1]Singman, Eric & Matta, Noelle & Silbert, David. (2014). Convergence Insufficiency Associated with Migraine: A Case Series. The American orthoptic journal. 64. 112-6. 10.3368/aoj.64.1.112.

Retrospective databank analysis was conducted of 174 participants between the ages of 13-84 (M=37 SD=19) recruited from an interdisciplinary concussion clinic (M=295 SD=609 days post-injury). Near point convergence (NPC) and subjective headache severity were obtained by a neurologist during routine clinical visits. Near point convergence was dichotomized: >5cm being CI, and <5 “normal.”  Current headache severity was measured using a self-report pain severity scale ranging from 0 (none) to 10 (most severe). Spearman rank-order correlation was used in order to elucidate the relationship between headache severity and CI.

Results suggest only a weak relationship between post-concussion headache severity and NPC status that failed to reach statistical significance (r=.171, p=.098). ).  NPC status explained only 3% of the variance in headache severity.

The results of this study suggest that headache and NPC measurements following concussion are very weakly associated. Given the episodic nature of headaches, it may be that statistically significant correlations are not evident unless there is a certain headache severity at time of NPC measurement. Future studies are needed in order to determine whether and to what extent injury severity or patient demographic characteristics mediate this relationship.