[A new cause of structural vertigo: superior semicircular canal dehiscence]

The medical history of vertigo must be updated to accommodate current knowledge. In 1998 a new cause of vertigo associated with a structural anomaly was reported: superior semicircular canal dehiscence. This condition causes vestibular and auditory disorders, which are frequently associated, and a well-directed medical history allows a suspected diagnosis to be reached: the subject may suffer from vertigo triggered by loud sounds (Tullio's phenomenon) and by changes in pressure within the ear or in the intracranial space, when Valsalva's manoeuvres are performed or on pressing on the tragus (Hennebert's sign). It is not uncommon for subjects to suffer from a chronic imbalance that is exacerbated by the aforementioned precipitating factors. One frequent auditory symptom of superior semicircular canal dehiscence is autophony in the dehiscent ear, associated with hypoacusis of its transmission. This article outlines the questions that must be included in the medical history of vertigo in order to determine whether these dehiscences are present or not. The diagnostic procedures that are best suited to confirming it are also addressed. Superior semicircular canal dehiscence can be resolved satisfactorily by surgery.