Diagnostic Criteria for Detection of Vestibular Schwannomas in the VA Population.

Objective: To investigate the prevalence of vestibular schwannoma (VS) and asymmetric sensorineural hearing loss in the Veterans Administration hospital population and analyze a more efficient method of diagnosing VS in a population with significant noise exposure. Study Design: Retrospective review of South Central (VISN 16) Veterans Administration hospitals. Methods: Record query for ICD-9 codes for asymmetric sensorineural hearing loss or VS between 1999 and 2012. Patient demographics, signs and symptoms at presentation, audiogram and imaging data, and management data were collected and analyzed. Audiograms from tumor patients were compared with controls matched for age, sex, combat experience, and medical comorbidity (2:1 control to case ratio). Results: The prevalence of VS was 1 per 1,145 patients in this population, with average age at diagnosis of 62. Patients with VS presented more commonly with unilateral tinnitus, rollover, and absent acoustic reflexes when compared with matched controls, but positive predictive value was low. Published criteria for defining hearing asymmetry showed variable sensitivity (51-89%) and low specificity (0-42%) for the detection of VS in this population. Criteria meeting the definitions of significant asymmetry with specificity for VS of 80% or greater were as follows: >15 dB threshold difference at 3 kHz and unilateral tinnitus, >=45 dB threshold difference at 3 kHz regardless of tinnitus, or when the word recognition score difference was >=80%. With serial audiograms 2.5 years apart or greater, a >=10 dB threshold increase at any frequency between 0.5 and 4 kHz had a 100% sensitivity for tumor and a >=10 dB increase at 3 kHz had a specificity of 84%. The majority of patients were observed, whereas only 30% had surgery. Patients who were observed were older than those treated with surgery or radiation (p

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