What is superior canal dehiscence?
Superior canal dehiscence is an opening (dehiscence) in the bone that covers the superior semicircular canal of the inner ear. It can result in symptoms that affect a person's balance and hearing.
What are the symptoms of superior canal dehiscence?
Symptoms of superior canal dehiscence can include vertigo (dizziness), oscillopsia (appearance of movement of stationary objects), autophony (hearing one's voice or self-generated sounds such as breathing or blinking louder than normal, sensitivity to loud sounds, and fullness/pressure in the ears.
The vertigo and oscillopsia commonly associated with superior canal dehiscence can be triggered by common activities that change the pressure in the brain or the middle ear. These activities include straining, coughing, sneezing, heavy lifting, exercising, and listening to loud noises.
What causes superior canal dehiscence?
The dehiscence can be congenital (present from birth) and may have occurred during the development of the inner ear. It can also be caused from certain infections as well as head trauma.
It is estimated that approximately 1 to 2% of the general population has abnormally thin bone covering their superior semicircular canal. The average age for diagnosis of superior canal dehiscence is approximately 45 years old. Approximately 33% of patients diagnosed will have superior canal dehiscence in each ear.
How is superior canal dehiscence diagnosed?
A thorough case history will be performed so the physician better understands the symptoms that the patient is experiencing. The physician may order several tests to assist in the diagnosis of superior canal dehiscence. These tests can include a CT scan of the temporal bone, which can show the opening in the bone covering the superior semicircular canal. Your physician may also order a hearing test and a vestibular evoked myogenic potential (VEMP).
A VEMP is a painless test. First, electrodes are taped to the skin of one side of a patient's neck. Next, sound is introduced into one ear – the ear on the same side of the head as the electrodes. Patients with SCD show increased sensitivity to sound as measured by the response of the neck muscle. The test helps identify the specific site of the injury to the inner ear, which can help determine the cause of SCD.
What are the treatment options for superior canal dehiscence?
Most patients with superior canal dehiscence can cope with their symptoms. They learn to avoid activities that cause the vertigo and oscillopsia. Seeking treatment from a certified vestibular physical therapy can be beneficial. They can provide patients with exercises to help improve balance and reduce fall risk.
For some patients, the symptoms of superior canal dehiscence are much more severe and can interfere with daily living. For those patients, plugging of the dehiscence through surgical repair may be necessary. Plugging the dehiscence has been shown to decrease or provide relief from the symptoms of superior canal dehiscence.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 7/31/2013…#15266