Features of superior canal dehiscence are -a) Positive Romberg's signb) Positive Tullio's phenomenonc) Positive Hennebert's signd) Oscillopsiae) Positive Dix-Hallpike maneuver

In 1998, Lloyd minor and colleagues described sound and/or presssure induced vertigo associated with bony dehiscence of the superior semicircular canal. Third window effect takes place in case of dehiscent superior semicircular canal whereby the dehiscent part of semicircular canal acts as a third window of inner ear. As a result, endolymph within the labyrinthine system continues to move in relation to sound or pressure changes which causes activation of the vestibular system.