Reduced binaural masking release in women with migraine despite normal hearing: a case-control study

Migraine is a neurological disorder associated with altered sensory processing, including auditory hypersensitivity. Although peripheral hearing is typically normal, central auditory mechanisms-particularly binaural interaction-may be affected. The masking level difference (MLD) test evaluates binaural processing at the level of the auditory brainstem.

This case-control study included 30 female patients with migraine and 35 age-matched healthy controls. All participants had normal otoscopic findings, type A tympanograms, and normal pure-tone thresholds. MLD testing was performed at 500 Hz. and 60 dB under homophasic (S₀N₀) and antiphasic (SπN₀, S₀Nπ) conditions. MLD values were calculated as the difference between homophasic and antiphasic thresholds. Group comparisons and ANCOVA were conducted.

Pure-tone thresholds were within normal limits but significantly higher in the migraine group (p < 0.001). No significant difference was observed in S₀N₀ thresholds. However, SπN₀ and S₀Nπ thresholds were significantly elevated in patients (p < 0.001). Accordingly, both MLD indices (S₀N₀-SπN₀ and S₀N₀-S₀Nπ) were significantly reduced in the migraine group (p < 0.001), and these differences remained significant after controlling for pure-tone averages.

Migraine patients demonstrate reduced binaural masking release despite normal peripheral hearing, suggesting impaired brainstem-level binaural processing. These findings support altered central auditory function in migraine and may reflect broader subcortical sensory dysfunction.