Migraine impairs the auditory protective mechanism: a potential biomarker

Migraine is a prevalent neurological disorder frequently accompanied by auditory symptoms such as tinnitus and hyperacusis. While their associations suggest shared neural mechanisms, objective evidence regarding the specific involvement of brainstem-mediated auditory efferent pathways in migraine remains limited. The medial olivocochlear reflex (MOCR) and the middle ear muscle reflex (MEMR) are two key auditory protective mechanisms, yet their integrity in migraine patients remains to be investigated. This study aimed to evaluate the functional integrity of the MOCR and MEMR pathways in migraine patients with and without comorbid tinnitus.

In this cross-sectional study, 143 participants were classified into four groups based on strict diagnostic criteria: healthy controls (HC, n = 44), tinnitus-only (T, n = 49), migraine-only (M, n = 25), and migraine with tinnitus (TM, n = 25). Groups were matched for age, sex, and hearing thresholds. All participants underwent comprehensive audiological assessments, including pure-tone audiometry, ipsilateral and contralateral acoustic reflex threshold (ART) testing to assess MEMR function, and distortion-product otoacoustic emissions (DPOAE) with contralateral suppression evaluation to assess MOCR function.

The migraine group (M) demonstrated significantly elevated contralateral ART (indicating MEMR impairment) at 500 Hz and 1000 Hz (p < 0.001) and globally reduced DPOAE suppression (reflecting MOCR dysfunction) (p < 0.001) compared to healthy controls. The TM group exhibited a similar pattern of MOCR and MEMR dysfunction to the M group, with no significant additive effect from tinnitus comorbidity. A clear gradient of contralateral ART impairment was observed across groups: HC < T < (M ≈ TM). Ipsilateral ART results showed less consistent abnormalities.

Migraine may be associated with specific dysfunction of brainstem auditory efferent pathways, particularly affecting both MOCR and MEMR systems, independent of peripheral hearing status. The convergent abnormalities in migraine patients with and without tinnitus indicate that auditory efferent disruption may be an intrinsic component of migraine pathophysiology. These findings support the potential of contralateral ART as an objective biomarker of migraine-related auditory pathway involvement, highlighting the clinical value of auditory assessment in migraine management and providing insights for the development of targeted therapeutic strategies.