All are characteristic features of superior semicircular canal dehiscence except?
(A) Third window phenomenon (B) SNHL (C) Tullio's phenomenon (D) Vestibular evoked myogenic potential is useful investigation.
(B) Ans. B. SNHLsymptoms of SSDC include* Tullio phenomenon - identifiable symptoms leading to a positive SCD diagnosis is sound-induced loss of balance. Patients showing this symptom may experience a loss of equilibrium, a feeling of motion sickness or even actual nausea, triggered by normal everyday sounds.* Vestibular evoked myogenic potentials (VEMP): In SSCD, loud tones evoke a sho-latency relaxation potential in the ipsilateral sternocleidomastoid muscle. Patients with SSCD typically have a lower-than-normal threshold for the VEMP response, and the amplitude of the VEMP waveform in an SSCD ear is greater for comparable stimulus intensities than in an ear without dehiscence. The VEMP test plays an impoant role in the evaluation of patients with suspected SSCD* Low-frequency conductive hearing loss is present in many patients with SCDS and is explained by the dehiscence acting as a "third window phenomenon"