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REVIEW PAPER
MIDDLE EAR MUSCLE DYSFUNCTION AS THE
CAUSE OF MENIERE’S DISEASE
1
John Curtin School of Medical Research, Australian National University, Canberra,
Australia
A - Research concept and design; B - Collection and/or assembly of data; C - Data analysis and interpretation; D - Writing the article; E - Critical revision of the article; F - Final approval of article;
Publication date: 2017-09-30
Corresponding author
Andrew Bell
Andrew Bell, JCSMR, 131 Garran Road, Australian National University, Canberra, ACT 2601, Australia, e-mail: andrew.bell@anu.edu.au
Andrew Bell, JCSMR, 131 Garran Road, Australian National University, Canberra, ACT 2601, Australia, e-mail: andrew.bell@anu.edu.au
J Hear Sci 2017;7(3):9-25
KEYWORDS
ABSTRACT
The symptoms of Meniere’s disease form a distinct cluster: bouts of vertigo, fluctuating hearing loss, low-frequency tinnitus, and a feeling of
pressure in the ear. Traditionally, these signature symptoms have pointed to some sort of pathology within the inner ear itself, but here the
focus is shifted to the middle ear muscles. These muscles, the tensor tympani and the stapedius, have generally been seen as serving only a
secondary protective role in hearing, but in this paper they are identified as vigilant gate-keepers – constantly monitoring acoustic input and
dynamically adjusting hearing sensitivity so as to enhance external sounds and suppress internally generated ones. The case is made that this
split-second adjustment is accomplished by regulation of inner ear pressure: when the middle ear muscles contract they push the stapes into
the oval window and increase the pressure of fluids inside the otic capsule. In turn, hydraulic pressure squeezes hair cells, instantly adjusting
their sensitivity. If the middle ear muscles should malfunction – such as from cramp, spasm, or dystonia – the resulting abnormal pressure
will disrupt hair cells and produce Meniere’s symptoms.
A wide-ranging review of Meniere’s disease and the middle ear muscles reinforces the link between the two. Since every striated muscle is
prone to dystonia – an involuntary contraction involving derangement of its underlying control loop – middle ear muscle dystonia would
lead to elevated pressure and abnormal hair cell function. The hypothesis is based on recognizing that the inner ear is a hydrostat – a cavity filled with fluid whose pressure is controlled by the middle ear muscles. Since the fluid is incompressible, even a slight contraction of the
muscles can increase the pressure in the labyrinth to 3 kPa. The effect of such a pressure on the sensing cells within is crucial. Outer hair cells
carry an internal turgor pressure of about 1 kPa, behaving physically like inflated balloons, and hence contraction of the middle ear muscles
can instantly overcome internal cellular pressure, switch off ion channels, and reduce hearing sensitivity.
This paper brings together supporting evidence and sets out major implications for Meniere’s disease, including possible treatments.
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