Time and geographic clustering of adult patients with unilateral idiopathic sudden sensorineural hearing loss.

For the preponderance of patients with unilateral idiopathic sudden sensorineural hearing loss (SSNHL), the etiology is unknown. The pathogenesis of disease and a definitive mechanism for this abrupt hearing loss has not yet been elucidated. We hypothesize that there is a time-clustered presentation for idiopathic SSNHL; from an epidemiological standpoint, this suggests an environmental or infectious etiology. At a tertiary referral center in the northeast United States, we have observed that adult patients with SSNHL present in clusters with interspersed intervals of time with no presentations.