To prevent AV or barotraumas in SCUBA divers, we recommend a thorough Eustachian tube function evaluation. Any dysfunction should be treated before engaging in SCUBA diving.

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A 28-year-old female diver presented with dizziness and difficulty clearing her left ear whilst scuba diving. Her pure-tone audiometry and tympanometry were normal. Testing of Eustachian tube function revealed tubal stenosis. Video-oculography revealed a predominantly torsional nystagmus while the patient was in the lordotic position. Fistula signs were positive. High-resolution computed tomography (HRCT) of the temporal bone revealed a diagnosis of bilateral superior semicircular canal dehiscence (SCDS). Cervical vestibular-evoked myogenic potential (cVEMP) testing showed that the amplitude of the cVEMP measured from her left ear was larger than that from the right. In electronystagmography (ENG), nosepinched Valsalva manoeuvres caused eye movements to be mainly directed counterclockwise with a vertical component. Tullio phenomenon was also positive for both ears. SCDS patients tend to be misdiagnosed and misunderstood; common misdiagnoses in these cases are alternobaric vertigo (AV), inner ear barotrauma, and inner-ear decompression sickness. It is difficult to diagnose vertigo attacks after scuba diving as SCDS; however, when the patient develops sound-and/or pressure-induced vertical-torsional nystagmus, HRCT should be conducted to confirm a diagnosis of SCDS.

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Patulous Eustachian tube is a condition in which the pressure and sound in the upper airway are transmitted to the middle ear through the Eustachian tube, and usually manifests as muffled hearing and autophony. This study was conducted in 14 patients with failure of Eustachian tube closure associated with scuba diving related accidents. All the patients underwent audiometric measurements, including hearing testing, tympanometry, and Eustachian tube function testing sonotubometry and impedance test , as well as were asked to respond to a questionnaire about their history of problems associated with scuba diving. The symptoms were mild in 8 of the 14 patients, including mild ear discomfort, 1 patient was diagnosed as having middle ear barotrauma MEB and 5 patients were diagnosed as having inner ear barotrauma IEB. In 1 patient with MEB, it was complicated by alternobaric vertigo AV. Eight of the 14 patients developed symptoms when rising to the surface, and 2 patients each suffered from AV and IEB during rapid descent. As compared to the findings in normal control divers, Eustachian tube function testing in divers with failure of Eustachian tube closure revealed a significantly larger degree of patency of the Eustachian tube, and moreover in subjects with PET, sonotubometry revealed that the Eustachian tube functions in the affected ear were significantly worse than those in the healthy ear. There were no significant differences in the results of Eustachian tube function testing between persons with and without inner ear dysfunction. We thought that during rapid descent, the rapid pressure variations and excessive positive pressure caused by the Valsalva maneuver could affect the inner ear ; moreover, the air in middle ear cavity expands by decompression when rising, and the resultant excessive positive pressure could affect the inner ear. To prevent pressure related injuries in scuba divers, we think that divers should be advised to rise as slowly as possible, and swallow their saliva repeatedly to reduce middle ear pressure.