New Imaging Technique Helps Detect Tinnitus
Approximately 50 million Americans occasionally or chronically have a “ringing in their ears,” an annoying sound that no one else can detect. That’s because they have tinnitus, a distracting, often debilitating condition that until now has been a challenge for clinicians to detect in the brain. Use of a noninvasive imaging technique called magnetoencephalography allows physicians to pinpoint the exact area of tinnitus in the brain.
The American Tinnitus Association defines tinnitus as the perception of sound in the ears or head when there is no external source responsible for it. The word “tinnitus” is of Latin origin and means “to tinkle or to ring like a bell,” although the sound can be hissing, clanging, pulsing, swishing, roaring, buzzing, even music. For about 12 million of the 50 million Americans who have tinnitus, the sounds are distressing enough to seek medical attention, while for another 2 million they are seriously debilitating.
Currently, clinicians use positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to study tinnitus in the brain. These imaging techniques are capable of indicating a general location in the brain that is producing symptoms of tinnitus. Researchers at Henry Ford Hospital in Detroit, Michigan, found that magnetoencephalography (MEG) allows them to pinpoint the site, which may then allow clinicians to target the exact location to treat with chemical or electrical therapies to reduce symptoms.
For the study, the researchers gathered MEG test results from 17 patients who had tinnitus and ten patients without it. For the tinnitus patients who had ringing in only one ear, the MEG imaging detected the most activity in the auditory cortex on the opposite side of the brain of the strongest perception of the sound. Participants who did not have tinnitus showed small areas of activity in the brain but none that were highly active. Currently only 20 locations in the United States, including Henry Ford Hospital, have an MEG scanner.
The exact physiological causes of tinnitus are not known, although there are several factors known to trigger it or make it worse. These include
Use of magnetoencephalography to more precisely detect tinnitus is a major step in the quest for effective treatment and a cure for this common condition.
American Tinnitus Association
EurekAlert October 3, 2009