Objective: Evaluate the relationship between objective audiometric and vestibular tests and patient symptoms in superior canal dehiscence (SCD) syndrome.
Study design: Retrospective chart review.
Setting: Tertiary care center.
Patients: Ninety-eight patients with SCD, preoperative threshold audiograms, cervical vestibular evoked myogenic potential (cVEMP) thresholds, and computed tomography (CT) imaging were included. Clinical reports were reviewed for self-reported SCD symptoms. Twenty-five patients completed the Hearing Handicap Inventory (HHI), Dizziness Handicap Inventory (DHI), Autophony Index (AI), and the 36-item Short Form Survey (SF-36).
Main outcome measures: Correlations between preoperative low-frequency air-bone gap (ABG), cVEMP thresholds, and symptoms (including HHI, DHI, AI, and SF-36). Symptoms included hearing loss, aural fullness, autophony, hyperacusis, tinnitus, vertigo, imbalance and sound-, pressure and exercise provoked dizziness. Secondary outcome measure: Correlations between changes of objective and subjective measures before and after surgery.
Results: Patients who reported hearing loss had larger ABGs at 250 Hz than patients without subjective hearing loss (p = 0.001). ABGs and cVEMP thresholds did not correlate with any other symptom. No significant correlation was found between ABG or cVEMP threshold and the HHI, DHI, AI or Health Utility Value (derived from the SF-36 quality of life score). Following SCD surgery, ABG decreased (p < 0.001), cVEMP thresholds increased (p < 0.001) and overall symptoms, handicap scores and quality-of-life improved; however, there was no significant relationship between these measures.
Conclusion: While threshold audiometry and cVEMP are important tools to diagnose SCD and monitor surgical outcomes, these measures showed no significant correlation with vestibular and most auditory symptoms or their severity.