U of U engineers discover reasons why some people get dizzy when hearing certain sounds
(KUTV) - Ever felt dizzy after hearing a certain sound with a distinct tone?
Researchers from the University of Utah, John Hopkins School of Medicine and the University of Mississippi have discovered why some people have this reaction to noise.
As the researchers monitored the neurons and inner ear fluid motion in a toadfish, it was discovered that the ear can send an incorrect signal to the brain that the head is rotating, when it's not. Hearing a certain sound can cause the ear to send an incorrect signal, thus creating the dizzy feeling.
“It’s very much like the feeling when they’ve had too much to drink. They get dizzy, and they feel nauseous, and they can’t see well and lose their balance,” Richard Rabbitt, senior author and Utah biomedical engineering professor, said in a news release. “What our paper is about is the biophysics of how that happens. How does sound excite the inner ear balance organs causing them to send the wrong head-motion signals to the brain?”
Approximately 1 in 100 people around the world have a congenital inner ear condition known as semicircular canal dehiscence. Meaning, the bone that protects the inner ear is thinning. This can lead to vertigo in response to sounds, changes in atmospheric pressure or coughing. This condition may make people feel as though they are drunk just by hearing certain tones; even the sound of someone's voice or musical instrument can have the same effect.
Normally, solid bone surrounds the inner-ear balance and hearing organs.
But in 1929, Italian biologist Pietro Tullio discovered that a hole in that bony enclosure can cause the inner ear semicircular canals to become sensitive to acoustic sounds like those that come from a trumpet, violin or piano. Even a high pitched conversation can cause trigger to sensitivity.
The study conducted at the University of Utah shows this condition can cause the eyes to rotate through an automatic reflex. Normally, this should stabilize the image in the eye during head movements. But, if the signal from the ear is wrong, the eye movements are also wrong, which can cause a feeling of dizziness.
“Your eyes will counterrotate the wrong way, and it will look like the world is spinning,” Rabbitt says. Fortunately, surgery to repair the dehiscence can help patients but researchers now understand the connection of how a small hole in bone can create a lifetime of debilitating dizziness for many."
These findings were published in the recent issue of Scientific Reports. Marta Iversen was the lead author of the study and is Utah biomedical engineering doctoral student.
The entire paper can be read here.