Why some sounds make you feel dizzy
Did you know that some sounds can make people feel dizzy? In fact, approximately one in 100 people feel this way. This is a congenital inner ear condition known as semicircular canal dehiscence — a thinning of the bone enclosing the inner ear that can lead to vertigo in response to certain sounds, changes in atmospheric pressure or even coughing.
Normally the hearing organs and inner ear are enclosed in solid bone. However, in 1929, an 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. This is known as the Tullio phenomena. Sounds like a sustained tone from a musical instrument such as a trumpet, violin or piano, or even a higher-pitched conversation can trigger Tullio phenomena. This condition causes the eyes to rotate through an automatic reflex which would normally stabilise the image in the eye during head movements. But in the case of Tullio phenomena, the signal from the ear is wrong and thus the eye movements are also wrong, causing the patient to feel dizzy.
In the case of Tullio phenomena, the signal from the ear is wrong and thus the eye movements are also wrong, causing the patient to feel dizzy.
The feeling is pretty much like being drunk after hearing certain sounds. People feel dizzy and even nauseous, and they can’t see well which causes them to lose their balance. Usually, it takes just seconds of a particular sound to be played for the patient to feel dizzy and the person can stay dizzy for many seconds after the tone has stopped playing.
Researchers from the University of Utah, Johns Hopkins School of Medicine and the University of Mississippi conducted a study to understand the biophysics of how this happens. The scientists used the finite element method (FEM) to simulate fluid motion and tissue deformation in the vestibular labyrinth (parts of the ear). They constructed a simple FEM model based on the geometry of the human superior canal with an opening (dehiscence) in the bone located halfway around the loop.
They monitored the neurons and inner ear fluid motion in toadfish, which have similar inner ear balance organs as humans. They found that the dizzying effect occurs when the sound generates pathological fluid mechanical waves in the semicircular canals of the ear. Under normal circumstances, inner ear fluid moves when you rotate your head and your eyes automatically counter-rotate to stabilise the image on the retina.
But when there is a hole in the bone, certain acoustic sounds cause the inner ear fluid to pump. As a result, the ear sends an incorrect signal to the brain that you’re rotating your head when you’re really not. Your eyes will counter-rotate the wrong way and you end up feeling dizzy.
This study provides an insight into what goes on in your ear and how a tiny hole can create such debilitating dizziness for patients. The good news is that this condition can be corrected with surgery, which helps alleviate the feeling of dizziness caused by certain sounds.
Source: Scientific Reports
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