Severe sudden sensorineural hearing loss related to risk of stroke and atherosclerosis

The cause of idiopathic sudden sensorineural hearing loss (idiopathic SSNHL)-diagnosed after excluding other causes of hearing loss, such as SSNHL associated with vestibular schwannoma (VS)-is unknown. The presumed pathogenesis of idiopathic SSNHL includes circulatory disorders (e.g., cochlear infarction). We tested the hypothesis that patients with SSNHL who are at high stroke risk will have a lower rate of VS compared to those with low stroke risk. The rationale is that the primary cause of SSNHL in patients with high stroke risk might be a circulatory disturbance. We conducted a retrospective study in six hospitals. Our sampling of SSNHL patients included those diagnosed with idiopathic SSNHL and VS-associated SSNHL. SSNHL patients who had a head MRI were stratified by severity of hearing loss and evaluated for differences in the detection rate of VS between the high-scoring CHADS₂ (CHADS₂-H-), an index of stroke risk, and low-scoring CHADS₂ (CHADS₂-L-) groups. We identified 916 patients who met the inclusion criteria. For severe hearing loss, the CHADS₂-H group had a significantly lower rate of VS than the CHADS₂-L group (OR 0 [95% CI 0.00-0.612]; P = 0.007). These results indirectly support the hypothesis that a primary cause of severe idiopathic SSNHL in those at high risk of stroke might be a circulatory disorder.