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Hearing
loss in Paget's disease has traditionally been thought to be multifactorial.
Causes proposed have included vascular shunts, invasion of the cochlea
by pagetic bone, compression of the auditory nerve in the internal
auditory canal, and fixation or stiffness in the ossicular chain.
Based on histologic, audiologic, and bone densitometric studies, it
has recently been proposed that changes in density or structure of
the bone surrounding the cochlea are responsible for both the conductive
and sensory components of pagetic hearing loss in nearly all cases.
Pagetic hearing loss progresses at a more rapid rate than presbycusis
does, and it can be severe. Treatment may prevent or slow the progress
of hearing loss in Paget's disease. Surgical treatment of the conductive
loss is usually not successful. In this audiogram the frequencies
in Hertz are displayed across the top of the graph. The hearing sensitivity
at each frequency is indicated with an x for hearing by air conduction
and by a bracket for hearing by bone conduction. This case example
of a left ear in a 72-year-old woman with Paget's disease involving
the skull illustrates a high-frequency sensory loss and a low-frequency
conductive loss. |
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