Researchers Uncover Potential Link Between Migraine, Cochlear Impairment

Using otoacoustic emissions (OAEs), researchers in Italy detected a potential subclinical cochlear impairment among migraineurs, which may represent the earliest sign of sensorineural damage in these patients. It could also serve as a tool for initial diagnosis and an opportunity to monitor disease course and treatment response over time, they said. Findings were published in Journal of Clinical Medicine.

Different cochlea-vestibular symptoms are commonly reported among migraineurs, and increasing evidence suggests a peripheral involvement of the inner ear in the condition, researchers explained.

Although no causal relationship between migraine and auditory discomfort has been established, “vascular, neurochemical, genetic, cortical, and central sensory processing have been speculated as causes of this observation,” they added.

Because a limited number of studies have been carried out on this subject, the authors sought to investigate the peripheral auditory pathway in untreated migraineurs using OAEs to detect alteration of cochlear functioning and a possible relationship with disease severity.

Fifty outpatients with episodic migraine were enrolled in the observational case-control study. Any patient who had taken corticosteroids up to 30 days before the neuro-otological examination was excluded, while 58 healthy volunteers made up the control group.

In addition to collecting demographic and migraine-related data, the researchers also carried out otoscopy, pure tone audiometry (PTA), an acoustic immittance test, and OAEs (transient-evoked [TEOAE] and distortion-product [DPOAE]) evaluations on participants. All individuals completed questionnaires regarding hearing difficulties in everyday life.

The average patient age was 36, and the average control age was 35; migraineurs reported a mean (SD) disease duration of 17 (12) years. Fifteen patients had migraine with aura, and 22% of the patient group reported an accompanied auditory symptom of ear fullness.

Analyses revealed:

• Compared with healthy control subjects, patients with migraine reported significant lowering mean DPOAE amplitudes observed at each frequency (P = .01 left; P =. 00003 right)
• Contralateral sound stimulus induced significant decrease in amplitudes of DPOAE (suppression) in migraineurs compared with controls (P = .004 left; P = .00002 right)
• Reduction of the scores of both DPOAE and their contralateral suppression were significantly related to the length of disease affection (odds ratio [OR], 0.020; 95% CI, 0.001-0.580; P = .023; and OR, 0.076; 95% CI, 0.007-0.771; P = .029, respectively)
• Altered DPOAE (and suppression) total responses exposed migraineurs to the risk of presenting with ocular (OR, 357.553; 95% CI, 2.114-60,461.505; P = .025) and/or auditory symptoms (OR, 1100.476; 95% CI, 2.612-4.636; P = .023) during the headache attack
• In the case of reduced DPOAE, the patients had an increased risk of suffering from migraine without aura (OR, 0.025; 95% CI, 0.001-0.466; P = .013)
• Lowest scores of DPOAE exposed patients to the highest consumption of painkillers (monthly average number) (OR, 0.007; 95% CI, 0.000-0.670; P = .033)

The presence of dopaminergic manifestations and/or allodynia during an attack were significant determinants of decreased contralateral suppression of DPOAE responses among migraineurs, the authors said, noting “TEOAE and TEOAE suppression scores did not show statically significant difference between patients and controls.”

Overall, findings indicate DPOAE may be used to identify potential reversible hearing impairment in this population, while “the presence of these alterations suggests that subtle sensorial affection may be an early sign of headache, a sort of additional ‘aura’ detectable by electrophysiologic study only.”

The analysis did not include patients with new-onset history of migraine and those who used triptans, marking limitations to the study.

“Our results confirm a potential cochlear impairment in migraineurs, occurring at the synaptic level between [medial olivocochlear] and [outer hairy cells] and targeting [calcitonin gene-related peptide] activity,” the authors concluded.

Reference

Albanese M, Di Girolamo S, Silvani L, et al. Distortion product otoacoustic emissions and their suppression as predictors of peripheral auditory damage in migraine: a case-control study. J Clin Med. Published online October 27, 2021. doi:10.3390/jcm10215007