Prospective Analysis of an Evidence-Based Symptom Set in Superior Canal Dehiscence Syndrome

Introduction: Superior canal dehiscence syndrome (SCDS) is characterized by a defect in the bone overlying the superior semicircular canal. This third mobile window generates an abnormal low-impedance pathway for sound/pressure transmission into the inner ear resulting in the characteristic symptoms. Objective: To perform a prospective analysis of symptoms in patients with SCDS. Methods: An aggregated symptom set was studied prospectively and compared with a healthy control group. The 31 items inquired about the presence and severity of symptoms. Initial comparison between both groups was performed using the Kolmogorov-Smirnov test and nonparametric Mann-Whitney U test. For analysis of the internal consistency, the Cronbach's alpha coefficient was determined. Finally, the prevalence of symptoms obtained in the present study was compared to the prevalence of symptoms obtained as part of a recent retrospective systematic review. Results: Responses from the 29 patients with SCDS in the case group and the 58 healthy controls were not normally distributed. Those with SCDS had a higher prevalence and more severe symptoms for almost all items. The Cronbach's alpha coefficient of 0.969 indicates an excellent internal consistency. The prospective prevalence of most symptoms was higher than the retrospective prevalence reported earlier. Conclusions: SCDS causes a variety of vestibular and auditory symptoms. This prospective study demonstrates that their prevalence and severity are higher than reported previously. This symptom set demonstrates excellent internal consistency and will serve as a foundation toward developing a disease-specific patient-reported outcome measure for SCDS.