title: Systematic review of the evidence for the etiology of adult sudden sensorineural hearing loss.
abstract: OBJECTIVE
  To determine the evidence for different etiologies of sudden sensorineural hearing loss (SSNHL) identified by clinical diagnostic tests in the adult population.
  
  
  METHODS
  Systematic literature review.
  
  
  METHODS
  Review of MEDLINE (1950-October 2009), EMBASE (1980-October 2009), and EBM Review databases in addition to manual reference search of identified papers. Randomized controlled trials, prospective cohort studies, and retrospective reviews of consecutive patients in which a clear definition of SSNHL was stated and data from consecutive patients were reported with respect to etiology of hearing loss. Three researchers independently extracted data regarding patient demographic information, diagnostic tests employed, and the identified presumed etiologies. Discrepancies were resolved by mutual consensus.
  
  
  RESULTS
  : Twenty-three articles met the inclusion criteria. The first group of papers searched for different etiologies among patients with SSNHL. Multiple etiologies were identified, including viral infection, vascular impairment, autoimmune disease, inner ear pathology, and central nervous system anomalies. The diagnosis for the majority of patients remained idiopathic. The second group of papers evaluated SSNHL patients with specific diagnostic tests such as autoimmune markers, hemostatic parameters, and diagnostic imaging.
  
  
  CONCLUSIONS
  The suspected etiologies for patients suffering sudden sensorineural hearing loss included idiopathic (71.0%), infectious disease (12.8%), otologic disease (4.7%), trauma (4.2%), vascular or hematologic (2.8%), neoplastic (2.3%), and other causes (2.2%). Establishment of a direct causal link between SSNHL and these etiologies remains elusive. Diagnostic imaging is a useful method for identification of temporal bone or intracranial pathology that can present with SSNHL as a primary symptom.
authors.affiliation: Division of Otolaryngology, Department of Surgery, University of Calgary, Calgary, Alberta, Canada. justin.chau@gmail.com
authors.forename: Justin K
authors.initials: JK
authors.lastname: Chau
authors.forename: June R J
authors.initials: JR
authors.lastname: Lin
authors.forename: Shahnaz
authors.initials: S
authors.lastname: Atashband
authors.forename: Robert A
authors.initials: RA
authors.lastname: Irvine
authors.forename: Brian D
authors.initials: BD
authors.lastname: Westerberg
mesh_terms: D000328:Adult; D019317:Evidence-Based Medicine; D003639:Hearing Loss, Sudden / Q000209:etiology*; D006801:Humans; D016032:Randomized Controlled Trials as Topic