Functional evaluation of the auditory brainstem in migraine patients using ABR and MLD tests

Abstract Background Migraine is a prevalent neurological disorder commonly associated with sensory disturbances, including phonophobia. These symptoms suggest possible involvement of central auditory pathways, particularly at the brainstem level, yet objective data remain limited. Objectives To assess auditory brainstem function in episodic and chronic migraine patients using auditory brainstem response (ABR) and masking level difference (MLD) tests and to explore correlations with migraine severity and disability. Methods A case–control study was conducted with 41 migraine patients (20 episodic, 21 chronic) and 41 age- and sex-matched controls. All subjects had normal peripheral hearing. Evaluations included pure tone audiometry, tympanometry, speech audiometry, acoustic reflexes, ABR, and MLD tests at 500 Hz and 1000 Hz. Migraine-related disability was measured using the Migraine Disability Assessment Test (MIDAS) scale. Statistical analyses involved ANOVA, Kruskal–Wallis, and correlation tests. Results There were no significant differences in PTA, SRT, or speech discrimination among groups (p > 0.05). However, acoustic reflexes were more frequently absent in chronic migraineurs (14.3%) compared to controls (0%), p = 0.035. MLD values were significantly reduced in migraine patients: MLD 500 (episodic, 8.90 ± 1.89; chronic: 9.71 ± 1.49; control: 4.46 ± 1.38; p < 0.001), and MLD 1000 (episodic: 9.20 ± 1.85; chronic: 9.76 ± 1.51; control: 4.63 ± 1.20; p < 0.001). ABR analysis revealed prolonged latencies and interpeak intervals in both migraine groups compared to controls, including LIII (p < 0.001), LV (p < 0.001), LI–III (p < 0.001), LIII–V (p < 0.001), and LI–V (p < 0.001). Correlation analysis showed that ABR abnormalities were positively correlated with migraine duration (r = 0.506–0.614, p < 0.001); frequency (r = 0.470–0.782, p < 0.001); and MIDAS scores (r = 0.594–0.855, p < 0.001). Females demonstrated significantly longer latencies in waves III and V than males (e.g., LV, female 5.98 ± 0.16 ms vs. male 5.88 ± 0.06 ms, p = 0.005). Conclusion This study demonstrates significant central auditory dysfunction in migraine patients, particularly those with chronic migraine. Prolonged ABR latencies and reduced MLD scores indicate auditory brainstem involvement, which correlates with migraine duration, frequency, and severity. ABR and MLD may serve as objective tools for identifying central auditory processing deficits in migraine.