Objective: This study adopted an inner ear test battery and MR imaging in patients with bilateral sudden sensorineural hearing loss (SSNHL) to investigate their causes, disease extent, and evaluate hearing outcome.
Patients and methods: From 1995 to 2014, 16 patients with bilateral SSNHL received audiometry, caloric test and MR imaging. Vestibular-evoked myogenic potential (VEMP) test was added to the test battery after 2000.
Results: Percentages of abnormal mean hearing level (MHL), cervical VEMP test, ocular VEMP test, and caloric test in patients with bilateral SSNHL were 100% (32/32), 100% (12/12), 100% (4/4), and 81% (26/32), respectively, implying that not only the cochlear part but also the vestibular part was severely affected in both ears. Causes of bilateral SSNHL were neoplasm in 5 patients, stroke in 5, meningitis in 1, and unknown in 5. Post-treatment MHL did not significantly differ from pre-treatment MHL indicating poor hearing outcome. Seven patients (44%) had passed away within 5years after onset, 2 patients were lost, and 7 patients survived.
Conclusion: Via MR imaging, causes of bilateral SSNHL were identified for 69% of cases. Both cochlear and vestibular endorgans/afferents were identified to be severely affected bilaterally by the vestibular test battery and resulted in poor hearing outcome. A high mortality rate (44%) indicates that bilateral SSNHL is an ominous sign for a more sinister underlying disease.
Keywords: Neurofibromatosis; Sudden deafness; Sudden sensorineural hearing loss; Vestibular-evoked myogenic potential.
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