Abeir O Dabbous, Nevin M Shalaby, Gihan M Ramzy, Hanan H El-Gendi
JHS 2011; 1(2): EA50-53
Background: Phonophobia describes sound intolerance, one of the characteristic symptoms associated with migraine attacks (Vingen et al., 1998).
Methods: This study included 25 normal hearing migraineurs with ictal phonophobia, tested with transient evoked otoacoustic emission (TEOAE) with and without contralateral acoustic stimulation (CAS) with white noise and speech in noise intelligibility (SIN) in the inter-ictal phase. They were compared to 25 well-matched controls.
Objective: to assess the function of the cochlear outer hair cells (OHC) and their efferent regulation by the medial olivocochlear reflex.
Results: Migraineurs showed statistically significant lower TEOAE than controls in the higher frequency bands as well as in overall response, overall reproducibility and mean AB value reflecting OHC dysfunction. But the majority of cases showed pass TEOAE bilaterally. After CAS, migraineurs showed statistically non-significant weaker TEOAE suppression than controls. Around 60% of ears had suppressed TEOAE overall response. Loudness discomfort level (LDL) was significantly lower than controls but only 3 cases showed hyperacusis, LDL and migraine duration were not correlated. TEOAE suppression was significantly correlated with word discrimination % in different signal to noise ratios (SNR) at certain frequency bands; but was not correlated with SNR of speech reception threshold in noise. TEOAE and SIN tests were not correlated with LDL or migraine duration.
Conclusion: Outer hair cells and olivocochlear reflex dysfunction can occur in migraineurs with phonophobia, but still the majority remains unaffected, suggesting other mechanisms of phonophobia than efferent system dysfunction, while the affected minority may have associated sub-clinical hyperacusis.
Keywords: contralateral suppression, efferent feedback, migraine, olivo-cochlear reflex, outer hair cells , Phonophobia