Hearing Health Guide
Definition
Sudden sensorineural hearing loss (SSNHL) is defined as a loss of 30 dBHL or greater at three or more consecutive frequencies developing within 72 hours. It most commonly affects one ear, often presents upon waking, and may be accompanied by tinnitus, aural fullness, or vertigo. SSNHL is treated as a medical emergency because corticosteroid treatment initiated within the first 2 weeks significantly improves outcomes. Outcomes worsen with each day of delay.
The classic presentation is waking up and noticing that hearing in one ear is significantly muffled or absent, sometimes described as hearing 'underwater' or through a pillow. Some people notice it first when they put a phone to the affected ear. It may be preceded by a popping sound.
Approximately 85–90% of SSNHL cases are idiopathic: no cause is found despite workup. Identified causes include viral infection (particularly herpes viruses), vascular events affecting cochlear blood supply, autoimmune inner ear disease, and rarely, acoustic neuroma.
Spontaneous recovery occurs in approximately 32–65% of cases, but recovery rates drop significantly with each passing week. Corticosteroids (typically oral prednisone or intratympanic dexamethasone injections) are the primary treatment, targeting inflammatory or immune mechanisms.
The AAO-HNS clinical practice guideline recommends that any patient with suspected SSNHL be seen by a physician within 14 days of symptom onset, and ideally within 24-72 hours. Emergency department evaluation is appropriate if same-day physician access is unavailable.
Outcomes vary: approximately one-third recover fully, one-third partially, and one-third have permanent hearing loss. Early treatment, less severe initial loss, and absence of vertigo are associated with better prognosis.
For those with permanent loss, audiological rehabilitation begins after recovery has plateaued (typically assessed at 3 months post-onset).
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