Superior canal dehiscence syndrome (SCDS) is a rare medical condition of the inner ear, leading to hearing and balance symptoms in those affected. The symptoms are caused by a thinning or complete absence of the part of the temporal bone overlying the superior semicircular canal of the vestibular system. There is evidence that this rare defect, or susceptibility, is congenital. There are also numerous cases of symptoms arising after physical trauma to the head. It was first described in 1998 by Dr. Lloyd B. Minor of Johns Hopkins University, Baltimore, USA.