What is Semicircular Canal Dehiscence?

Imagine for a minute that certain sounds had power over you. The power to make your head spin and shake your balance… it’s not a scene from a science fiction novel or the latest horror movie. It’s a real-life condition that affects an estimated one to two percent of the population, and it’s one that researchers are now taking a closer look at.

What is semicircular canal dehiscence

First identified and described over 70 years ago, what was once known as the Tullio phenomenon has since become known as Superior canal dehiscence syndrome (SCDS) or Superior semicircular canal dehiscence. Symptoms of this condition include vertigo often caused by certain noises or changes in pressure caused by sneezing or coughing.  Those with semicircular canal dehiscence may also have chronic balance problems.

Experts long wondered as to the cause of semicircular canal dehiscence. As technology improved, so did their ability to look deeper into the ear to better understand why these symptoms occurred. We now know the answer.

What causes semicircular canal dehiscence

The structures of the inner ear are crucial to more than just hearing. They are also key to maintaining balance and interpreting directional movement. According to recent research, it is a structural difference here that is behind semicircular canal dehiscence.

The semicircular canals of the inner ear are fluid-filled structures that house the hair-like structures that pick up sound vibrations as part of hearing. The semicircular canals also help us keep our balance. When the bone that houses the inner ear and its semicircular canals has a hole or thinning of the bone, it disrupts the function of the semicircular canals causing false signals about balance.

The research

In findings published in Scientific Reportsresearchers from the University of Utah, Johns Hopkins School of Medicine and the University of Mississippi outlined just what they have discovered about the why behind the still relatively unknown semicircular canal dehiscence.

What the team found was that when there is a hole in the bone around the inner ear, certain tones can influence the fluid of the inner ear. This causes a signal to the brain that there has been a change in direction (movement of the head) when, in fact, there hasn’t been one. The brain signals to the eyes to then adjust to the change in direction. This causes vertigo that is characteristic of semicircular canal dehiscence. These valuable findings were the result of the team’s monitoring of neurons and inner ear fluid motion in toadfish, which, according to the team, have similar inner ear balance organs as humans.

“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,” says senior author and Utah biomedical engineering doctoral student, Richard Rabbitt.

The good news is, once diagnosed, semicircular canal dehiscence can be resolved with surgery.

If you are affected by vertigo, dizziness or other balance issues, schedule an appointment with your physician or our office to determine the underlying cause, discuss treatment options, and, in some cases, prevent future problems such as hearing loss.

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