Natural History of Hearing Loss in Sporadic Vestibular Schwannoma

Hearing loss is the most common and earliest symptom of VS at diagnosis. The most common pattern of hearing loss is asymmetric SNHL. Roughly half of the patients at time of diagnosis have SH in the affected ear. Throughout its natural history, patients with SH maintain SH at 94% to 95% after 1 year, 73% to 77% after 2 years, 56% to 66% after 5 years, and 32% to 44% after 10 years. Better hearing at the time of diag-nosis in terms of higher SDS and lower PTA is otoprotective because these patients maintain good hearing for a longer period of time. For patients newly diagnosed with VS, it is likely their hearing will continue to deteriorate during a 10-year observa-tional period despite small initial tumor size or lack of tumor growth. The mechanism responsible for progressive hearing loss in sporadic VS is still under investigation.