Quantitative Oculomotor Abnormalities in Episodic and Chronic Migraine: A Cross-Sectional Comparative Study

Migraine is a primary headache disorder accompanied by potential oculomotor dysfunction, yet the differences in eye movement performance between episodic migraine (EM) and chronic migraine (CM) remain insufficiently clarified. This study aimed to compare clinical headache-related indicators and quantitative oculomotor task parameters among healthy controls, total migraine patients, EM and CM subgroups, and explore characteristic oculomotor differences between EM and CM.

This study adopted a cross-sectional design. A total of 242 patients with migraine and 47 healthy controls were included. Of the patients with migraine, 199 were classified as having episodic migraine and 41 as having chronic migraine; two could not be classified because of missing headache-frequency data. Demographic and clinical data including sex, age, Headache Impact Test-6 (HIT-6) and Migraine Disability Assessment (MIDAS) scores were collected. All participants completed a battery of quantitative oculomotor paradigms, including prosaccade, gap saccade, overlap saccade, antisaccade, memory-guided saccade and smooth pursuit tasks. Group differences were primarily evaluated using independent-samples t tests, with Welch's correction applied when variances were unequal. Effect sizes and 95% confidence intervals were reported, and Mann-Whitney U-tests were performed as sensitivity analyses.; P < 0.05 was defined as statistically significant. Given the exploratory nature of the analyses, no adjustment for multiple comparisons was applied.

Sex and age showed no intergroup differences (P>0.05). CM had higher HIT-6 and MIDAS scores than EM (P<0.05). Compared with controls, patients with migraine had lower antisaccade peak velocity (mean difference, -129.95 °/s; 95% CI, -210.74 to -49.17; Cohen's d=0.50), whereas the difference in antisaccade error rate was not robust in the sensitivity analysis. Compared with EM, CM showed abnormalities in saccade latency, completion time, velocity, memory-guided saccade accuracy, and inhibition failures, with absolute Cohen's d values ranging from 0.35 to 0.58.

Migraine patients manifest impaired inhibitory control during antisaccade execution compared with healthy individuals. Distinct quantitative oculomotor abnormalities including prolonged saccade latency, reduced saccadic velocity, decreased memory-guided saccade accuracy and elevated inhibitory failure frequency are prominent in CM rather than EM. Quantitative oculomotor assessments measures may represent candidate correlates of migraine subtype, but these exploratory findings require validation in larger, independent cohorts.