Superior canal dehiscence syndrome (SCDS)

Superior canal dehiscence syndrome (SCDS) happens when the thin bone covering one of the inner ear’s balance canals is missing or extremely thin, creating an extra opening — a “third window” — into the inner ear. This can cause dizziness triggered by loud sounds or pressure changes, and make you hear your own voice, heartbeat or footsteps unusually loudly. SCDS is diagnosed by an ENT specialist using a high-resolution CT scan and hearing and vestibular tests, and surgical repair is an option when symptoms are significant. Vestibular physiotherapy can’t close the opening, but it can help with ongoing imbalance, managing triggers and recovery after surgery. At McKelvie Physiotherapy in Pickering, we’ll be clear about what rehab can and can’t do for you.

What is superior canal dehiscence?

Your inner ear has three semicircular canals on each side that sense head rotation. Normally, each canal is fully encased in bone. In superior canal dehiscence, the bone over the superior (top) canal is missing or extremely thin.

That gap acts as a “third window” into the inner ear. Sound and pressure that should only reach the hearing organ can now stir the fluid in the balance canal — so loud noises, coughing or straining can make you feel dizzy, and sounds from inside your own body can seem amplified.

SCDS was first described in 1998 (Minor et al., 1998). It’s uncommon, and it can affect one or both ears.

What causes superior canal dehiscence?

The exact cause isn’t fully understood. The bone over the superior canal may be thin from early in life, and symptoms often appear later in adulthood. In some people, an event such as a head injury or heavy straining seems to bring symptoms on, although this isn’t always the case.

Not everyone with thin bone over the canal has symptoms — which is one reason the diagnosis has to be made carefully by a specialist.

What are the symptoms of superior canal dehiscence?

• Dizziness, vertigo or a sense of the world moving triggered by loud sounds
• Dizziness triggered by pressure changes — coughing, sneezing, straining, lifting or blowing your nose
• Autophony — hearing your own voice, breathing, chewing, heartbeat or footsteps unusually loudly
• A feeling of fullness in the ear
• Pulsing tinnitus in time with your heartbeat
• Ongoing imbalance or unsteadiness

How is superior canal dehiscence treated?

SCDS is diagnosed and treated by an ENT specialist (often a neurotologist):

• Diagnosis — a high-resolution CT scan of the temporal bone shows the opening, and hearing and vestibular tests — such as vestibular evoked myogenic potentials (VEMPs) and a hearing test — confirm that the inner ear is behaving the way SCDS predicts (Ward et al., 2017).
• Conservative management — many people with milder symptoms do well by understanding the condition and avoiding or reducing their triggers.
• Surgical repair — when symptoms are significant, surgery to plug or resurface the affected canal is the definitive treatment and has been shown to be effective (Ward et al., 2017).

Physiotherapy’s role in SCDS is limited and supportive — and we’ll tell you that up front. Vestibular rehab can’t close the opening or stop sound- and pressure-triggered symptoms. Where it can help:

• Ongoing imbalance — balance and walking exercises to build steadiness and confidence
• Managing triggers — practical strategies for everyday activities, with exercises chosen to avoid provoking your symptoms
• After surgery — sealing the canal means your brain has to adjust, and vestibular rehab helps that recovery once your surgeon clears you

Because SCDS can look like other inner-ear conditions, a thorough vestibular assessment also helps make sure nothing else — such as BPPV — is adding to your dizziness.

1. 01

   Clarify

   A vestibular assessment with infrared video goggles to understand your symptoms and rule out other treatable causes, with ENT referral advice if SCDS is suspected.

2. 02

   Support

   Balance training and practical trigger-management strategies, tailored so exercises don’t provoke your sound- or pressure-related symptoms.

3. 03

   Recover

   If you have repair surgery, a graded post-operative program of gaze, balance and walking exercises to help your brain adjust.

Why choose McKelvie Physiotherapy for SCDS?

• Honest about scope — we’ll explain what vestibular rehab can and can’t do for SCDS before you start.
• Advanced diagnostic technology — we use infrared video goggles (video-oculography) to record eye movements the naked eye can’t see, so your diagnosis is based on evidence, not guesswork.
• Led by an Advanced Vestibular Physical Therapist (AVPT) — vestibular rehab is our clinical focus, not a sideline.
• Works with your specialists — we work closely with local ENT specialists, including before and after surgery.
• One-on-one care in private rooms — in person in Pickering, at home across the GTA, or virtually anywhere in Ontario.
• Direct billing to many major insurers — and no referral needed.