Jourdy et al (2010) revisited the question: "Does the incidence of idiopathic sudden sensorineural hearing loss (ISSNHL) vary across the year?" ISSNHL occurs in approximately 12 per 100,000 persons per year. Among the possible etiologies are vascular occlusion, labyrinthine membrane breaks, viral infections, and more. Viral infections are often considered because hearing loss is associated with many human viral diseases (herpesvirus, cytomegalovirus, umanimmunodeficiency virus, etc) and because ISSNHL often appears to be preceded by an upper respiratory infection (URI).
The authors performed a retrospective analysis of 97 adult patients (53 women and 44 men) with a mean age of 52 years evaluated between 2005 and 2008. In essence, with due consideration for various criteria of hearing loss (20 dB versus 30 dB), the authors found no evidence of an uneven monthly distribution or incidence of ISSNHL. Of note, within their 97 patients, only 19 individuals reported a URI before or concurrent with the onset of ISSNHL.
For more Information, References and Recommendations
Jourdy DN, Donatelli LA, Victor JD, Selesnick SH. (2010) Assessment of Variation Throughout the Year in the Incidence of Idiopathic Sudden Sensorineural Hearing Loss. Otology & Neurotology 31(1):53-57.