The Auditory Nerve.
Diseases of the auditory nerve may be due to tumors, softening, syphilis, chronic inflammation, meningitis, aneurism, otitis media, and labyrinthine disturbances. Quinine and the salicylates also affect the hearing.
Hyperacusis (hyperesthesia) is that condition when certain or all sounds are abnormally increased. It sometimes occurs in hysteria and in the course of cerebral diseases. Paralysis of the stapedius is also followed by an abnormally acute hearing.
Dysacusis, difficult hearing, may be due to any of the above-mentioned causes that affect the auditory nerve, but more frequently to middle-ear diseases.
Tinnitus aurium is that condition where abnormal sounds occur, such as ringing, crackling, buzzing, whirring, or tickling sensations, and may be due to accumulations of cerumen, labyrinthine disturbances, otitis media, anemia, aneurism, and sometimes it occurs as an aura in epilepsy. These abnormal sounds may be more or less constant or exaggerated at night and when the system is depressed or impoverished.
Treatment.—In the treatment of diseases of the auditory nerve, a careful and patient study must be made to determine its cause, and, if possible, remove it. The general health is to be considered and placed in the best possible condition. Where due to specific causes, the antisyphilitis will be used. Galvanism should be tried. This lesion is for the specialist rather than the general practitioner, and should be referred to the aurist.
Ménière's Disease: Auditory or Labyrinthine Vertigo.
In 1861 Ménière described an aural vertigo, where the attack came on suddenly and occurred as a paroxysmal affection, the characteristic symptoms being vertigo, deafness, and tinnitus aurium. (Meniere's)
Etiology.—The disease occurs more frequently in men than in women, and generally after the age of thirty-five. It is probably due to labyrinthine disturbances.
Pathology.—But little is known of its true pathology, and whether the lesion be in the semicircular canals or in the cerebral centers, is not known.
Symptoms.—The attack comes on suddenly, with the sensation of being struck. With the dizziness, there comes a sense of nausea, which rapidly increases, ending in vomiting of bile. In mild cases, the patient, though quite dizzy, retains consciousness, but when severe, he may fall unconscious. Deafness and tinnitus usually are present during an attack.
The attacks recur at irregular intervals, varying from a day to several months.
Prognosis.—The prognosis is uncertain, some cases recovering, while others grow progressively worse until deafness is confirmed.
Treatment.—The treatment is not very satisfactory. Charcot recommended quinine in twenty-grain doses daily, to be continued for several weeks. Gowers advises sodium silicylate in five-grain doses, while the bromids are suggested by others.