Vertebrobasilar System Laterality and Idiopathic Sudden Sensorineural Hearing Loss.

INTRODUCTION: The etiology of idiopathic sudden sensorineural hearing loss (ISSNHL) remains elusive, with vascular compromise as a proposed cause. This study aimed to explore the correlation between the vertebrobasilar vascular system laterality (VBVSL) and ISSNHL laterality. METHODS: We conducted a retrospective analysis of consecutive patients diagnosed with ISSNHL from 2015 to 2020. The VBVSL pattern was established via magnetic resonance imaging scans by a neuroradiologist. ISSNHL occurring contralaterally to the basilar artery (BA) curvature or ipsilaterally to the dominant vertebral artery (VA) was designated as a "positive match," with all other scenarios classified as a "negative match." RESULTS: Our study included 191 ISSNHL patients (median age 57 years, 89 males, 93 right ears). The majority of patients did not exhibit a positive match between ISSNHL laterality and the sides of BA curvature or dominant VA (28.8% and 36.6% for BA and VA, respectively). Notably, VA-positive match patients were significantly older than VA-negative match patients (59 vs. 53 years, p = 0.043), with a similar trend observed in BA-positive match compared to BA-negative match (59 vs. 54.5 years, p = 0.057). However, there was no significant difference in any other clinical, audiometric, or outcome factors between the positive and negative match groups. CONCLUSION: The findings suggest no association between VBVSL and ISSNHL laterality. Furthermore, patients in the positive match group did not exhibit distinct clinical or audiometric features compared to those without a match.

Could the Audiometric Criteria for Sudden Sensorineural Hearing Loss Miss Vestibular Schwannomas?

OBJECTIVE: To investigate the likelihood of missing a vestibular schwannoma (VS) diagnosis in patients who present with a sudden hearing loss (SHL) that does not meet the most accepted audiometric criteria for sudden sensorineural hearing loss (SSNHL) (a decrease of ≥30 dB at three consecutive frequencies). METHODS: All adult patients (>18 years) diagnosed with SHL of any severity in a tertiary care referral medical center between 2015 and 2020 and who underwent an MRI scan to rule out VS were included. Statistical analyses were conducted to evaluate the difference between the rate of VS among patients with an initial audiogram, which met the abovementioned criteria, and those who did not. Other audiometric criteria for SNHL were also evaluated (≥10 dB at ≥2 frequencies and ≥ 15 dB at one frequency). RESULTS: Of the 332 patients included in the study, 152 met the audiometric criteria for SSNHL, and 180 did not. Both groups had a similar VS rate (8.6% vs. 8.9%, p = 0.914). Similar results were found when other audiometric criteria for asymmetric SNHL were analyzed. In a subgroup analysis of patients with VS-associated SSNHL, neither the tumor size nor the Koos classification was associated with any of the audiometric criteria systems. CONCLUSION: There should be a high index of suspicion for the presence of VS in patients with an SHL of any severity. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:670-675, 2023.