Disorders of hearing are very common and, in severe cases, they may interfere with communication, causing significant disability. In some cases, hearing loss is due to a disorder of the ear canal or the middle ear, but inner-ear disorders can also cause hearing problems. The inner ear also contains the vestibular apparatus, which helps to maintain the sense of balance. Inner-ear disorders may therefore lead to other symptoms such as dizziness.
This section starts by discussing all types of hearing loss from partial loss of hearing to total deafness. Hearing defects that are due to disorders of the inner ear, including noise-induced hearing loss and tinnitus (various sounds heard in one or both ears in the absence of an external source), are then covered in greater detail.
Problems in other parts of the ear that may cause hearing loss or deafness are covered elsewhere in the guide (see Outer- and middle-ear disorders), as is hearing loss or deafness that is present from birth (see Congenital deafness).
Inner-ear disorders do not only affect hearing; if the vestibular apparatus is disturbed, the sense of balance may be disrupted. Three common inner-ear disorders that affect balance – motion sickness, labyrinthitis, and Ménière’s disease – are described in this section. All of these disorders may cause symptoms such as dizziness and nausea. Ménière’s disease can also lead to hearing loss. The final article in this section discusses acoustic neuroma, a rare, noncancerous tumour affecting the vestibulocochlear nerve, which connects the inner ear to the brain.
For further information on the structure and function of the ear, see Ears, Hearing, and Balance.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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