Although uncommon, dive-related permanent hearing loss resulting from ear barotrauma or inner ear decompression sickness is possible. If the injury causes permanent unilateral (one ear only) hearing loss or impairment, subsequent diving may place the individual at risk for permanent bilateral hearing loss, as the uninjured ear would be at risk of injury. It is for this reason that most physicians counseling individuals following such injuries, recommend against a return to diving. This recommendation applies to all monaural (one sided hearing) individuals, regardless of the cause of unilateral hearing loss or impairment.
An additional population for whom diving is often discouraged or where extreme caution is advised includes those that have undergone cochlear implants, ossicle surgery or tympanic membrane repair (myringoplasty). Diving places individuals with this medical history at risk of damage to the surgical repair and consequent hearing loss. For divers who have undergone such procedures, or suffered permanent hearing loss from ear barotrauma, extreme caution is often recommended and close consultation with an ENT physician prior to diving is highly advised.
It is important to mention that bilateral hearing impairment (either congenital or acquired) is not necessarily a medical contraindication to diving per se. However, in cases of bilateral hearing impairment, a diving environment may pose potential difficulties with surface communications, both with other divers and/or with crew members. Obstructed communications in cases regarding boat traffic, divers recall and other unforeseen circumstances may result in delayed emergency response, injury or death.