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Posted by Sandy McCroskey
In Reply to: The link between tinnitus and TMJ posted by Anon
from Advance for Audiologists: www.advanceforaud.com/aawebexclusive.asp?issue=18
Unilateral Tinnitus: New Approach to Treatment
By Danielle Campbell
Robert Levine, MD, a neurologist at Massachusetts Eye & Ear Infirmary in Boston
has formulated a theory concerning a somatic system-related origin of unilateral
tinnitus in some patients. He bases his theory on what has been observed in animal
neurological systems.
It appears that ringing heard in the ears and/or the head also could be caused by
influences on the nervous system that originate in places other than the ears.
"We have a theory that tinnitus in humans is caused by an imbalance in the
auditory parts of the brain due to somatic influences from the head and neck," he
said.
Researchers know that there are pathways in the parts of animal brains subserving
the temporomandibular joint (TMJ), earlobe, neck, face and dental regions and the
dorsal division of the cochlear nucleus on that same side of the body. When an
injury occurs to the face, jaws, neck or teeth, some interaction occurs among
nerves that subserve the pain in these areas and the auditory part of the brain.
The nerves associated with these areas appear to communicate but do so in the
brain rather than in the ear, Dr. Levine told ADVANCE. This may explain why some
people with TMJ syndrome, whiplash or dental ailments also have tinnitus but do
not exhibit hearing problems. It also may shed light on why some people with the
same type of hearing loss may be affected differently by tinnitus, if at all.
The researcher has applied his new theory of tinnitus etiology to assessment and
treatment of the condition, which typically has escaped a definitive course of
therapy.
A study he participated in with Jennifer Melcher, PhD, and Irina Sigalovsky
demonstrated through functional magnetic resonance imaging (fMRI) scans of the
inferior colliculus of the brain that people with unilateral tinnitus have
increased activity in the brain area that corresponds to the affected ear.
"This is an objective measurement of their tinnitus," Dr. Levine said.
Approximately 75 percent of patients can change the sound of their tinnitus to
make it less distracting by forcefully contracting the muscles of the head and
neck. In a few patients this has led to new ways of controlling the condition.
For more information, visit Dr. Levine's website at epl.meei.harvard.edu/~ral.
Danielle Campbell is assistant editor of ADVANCE. Unilateral Tinnitus: New
Approach to Treatment
