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Meniere’s disease is a disorder of the inner ear which causes episodes of vertigo, ringing in the ears (tinnitus), a feeling of fullness or pressure in the ear, and fluctuating hearing loss. The area of the ear affected is the entire labyrinth, which includes both the semicircular canals and the cochlea.
A typical attack of Meniere’s disease is preceded by fullness in one ear. Hearing fluctuation or changes in tinnitus may also precede an attack. A Meniere’s episode generally involves severe vertigo (spinning), imbalance, nausea and vomiting. The average attack lasts two to four hours. Following a severe attack, most people find that they are exhausted and must sleep for several hours. There is a large amount of variability in the duration of symptoms. Some people experience brief “shocks”, and others have constant unsteadiness. High sensitivity to visual stimuli (visual dependence) is common. During the attack the eyes jump (this is called “nystagmus”).
A particularly disabling symptom is a sudden fall. These typically occur without warning. These falls are called “otolithic crisis of Tumarkin”, from the original description of Tumarkin (1936). They are attributed to sudden mechanical deformation of the otolith organs (utricle and saccule), causing a sudden activation of vestibular reflexes. Patients suddenly feel that they are tilted or falling (although they may be straight), and bring about much of the rapid repositioning themselves. This is a very disabling symptom as it occurs without warning and can result in severe injury. Often destructive treatment (e.g. labyrinthectomy or vestibular nerve section) is the only way to manage this problem. Other otologic conditions also occasionally are associated with Tumarkin type falls (Black et al, 1982; Ishiyama et al, 2003). See here for more information about drop attacks.
Meniere’s episodes may occur in clusters; that is, several attacks may occur within a short period of time. However, years may pass between episodes. Between the acute attacks, most people are free of symptoms or note mild imbalance andtinnitus.
Meniere’s affects roughly 0.2% of the population (click here for more details about the epidemiology). Meniere’s disease usually starts confined to one ear but it often extends to involve both ears over time so that after 30 years, 50% of patients with Meniere’s have bilateral disease (Stahle et al, 1991). There is some controversy about this statistic however — some authors, for example Silverstein, suggest that the prevalence of bilaterality is as low as 17% (Silverstein, 1992). We suspect that this lower statistic is due to a lower duration of follow up and that the 50% figure is more likely to be correct. Other possibilities, however, are selection bias and different patterns of the disease in different countries. Silverstein suggested that 75% of persons destined to become bilateral do so within 5 years.
In most cases, a progressive hearing loss occurs in the affected ear(s). A low-frequency sensorineural pattern is commonly found initially, but as time goes on, it usually changes into either a flat loss or a peaked pattern
Hair cell death: Conventional thought is that repeated attacks of Meniere’s kills hair cells in the inner ear. This is a gradual process over years, but frequently resulting in unilateral functional deafness. Cochlear (hearing) hair cells are the most sensitive. Vestibular hair cells seem more resilient but there is also a slow decline in the caloric response in the diseased ear over roughly 15 years (Stahle et al, 1991).
2. Mechanical changes to the ear. Mechanical disruption of the inner ear is also likely with dilation of the utricle and saccule of the ear being a well known pathological finding. The saccule may dilate so that in later stages, it is adherent to the underside of the stapes footplate. This mechanical disruption and distortion of normal inner ear structures may result in the gradual onset of a chronic unsteadiness, even when patients are not having attacks. The periodic dilation and shrinkage of the utricle is also a reasonable explanation for periodic attacks of another inner ear disorder, BPPV. Finally, it also seems likely that there may be rupture of the suspensory system for the membranous labyrinth. This might create some mechanical instability of the utricle and saccule and consequently some chronic unsteadiness.
There is presently no evidence that Meniere’s disease kills the cochleovestibular nerve (see Kitamura et al, 1997). Thus the term “nerve deafness” is inappropriate.