Understanding the Inner Ear: Superior Canal Dehiscence

Scientists have long known that the workings of the inner ear are important to your overall health.

In fact, problems with the inner ear can lead to balance, hearing, and sight problems. Superior canal dehiscence syndrome (SCDS) is one such disorder of the inner ear with many harmful symptoms that can impact your broader health.

Though rare, SCDS can lead to serious consequences. And it’s important to understand the warning signs and treatment options.

What Is Superior Canal Dehiscence?

Your inner ear is made up of a system of passages and canals.

Within that system, two “window” openings are responsible for moving sound and air pressure in your ear. SCDS (sometimes called superior semicircular canal dehiscence) begins when a third window is created and redirects the pressure in this inner ear system.

This window forms when the bony covering of the semicircular canal (near the top of the ear) doesn’t exist or is too thin. Without that covering, the extra opening leads to balance, vision, and hearing problems.

Doctors don’t know for sure what causes the defect in the covering, but theories include failure to fully form in utero, thinning of the bone as part of aging, and head trauma.

Superior Canal Dehiscence Symptoms

Most symptoms of SCDS are either vestibular (balance-related) problems or auditory (hearing) problems.

Vestibular symptoms

  • Chronic unsteadiness
  • Vertigo or involuntary eye movement (nystagmus) caused by loud sounds or pressure
  • Oscillopsia (objects in visual field appear to move rapidly) caused by loud sounds or pressure

Auditory symptoms

  • Tinnitus (ringing, buzzing, or roaring sound in the ear)
  • Autophony (hearing internal body sounds more loudly, like creaking joints, pulse, and breathing)
  • Low-frequency conductive hearing loss
  • Increased sensitivity to bone-conducted sounds
  • Feeling of fullness in the ear

Other symptoms of SCDS

How Does This Differ from Other Inner Ear Issues, like Meniere’s Disease?

Meniere’s disease is a more common inner ear disorder with symptoms that overlap with SCDS. Meniere’s usually develops as people age and can lead to hearing loss, vertigo, and tinnitus. However, Meniere’s is the result of fluid buildup in the inner ear that creates extra pressure and affects balance. A CT scan can separate SCDS from Meniere’s by detecting the third opening in the inner ear typical of SCDS.

Superior Canal Dehiscence Treatment

If you have SCDS, you should consult with an audiologist and an otolaryngologist.

  • Surgical options can repair the covering of the superior canal, which often requires removing part of the skull, although less-invasive techniques are in development.
  • Hearing aids are also an option for people with SCDS, although they do not help symptoms other than hearing loss.
  • In some cases, simply avoiding situations that induce symptoms (like places with a lot of loud noises) can help manage discomfort.

For more, visit the Ear, Nose, and Throat specialists at UPMC.