What are the symptoms of dehiscence syndrome?

September 28, 2025 •

4 min read

Affecting an estimated 1-2% of the population, superior semicircular canal dehiscence (SCDS) is a rare inner ear condition. Here, we'll explore what are the symptoms of dehiscence syndrome and what causes these unique auditory and vestibular disturbances, which are often misdiagnosed.

Quick Summary

Dehiscence syndrome symptoms include sound- and pressure-induced vertigo, autophony (hearing internal body sounds like your heartbeat), pulsatile tinnitus, and a type of low-frequency hearing loss. Other signs include oscillopsia and aural fullness.

Key Points

Rare Inner Ear Disorder: Dehiscence syndrome, or SCDS, is caused by a bony defect in the inner ear's superior semicircular canal.
Distinctive Auditory Issues: Symptoms include hearing your own voice or heartbeat loudly (autophony and pulsatile tinnitus) and hypersensitivity to sound (hyperacusis).
Triggered Vertigo: Loud noises, pressure changes (like coughing or straining), and head movements can trigger episodes of dizziness and vertigo.
Visual and Balance Disturbances: Patients may experience oscillopsia (objects appearing to move) and chronic unsteadiness.
Diagnostic Process: A specialized CT scan and Vestibular Evoked Myogenic Potential (VEMP) testing are used to confirm the diagnosis.
Effective Treatment Options: Management ranges from avoiding triggers for mild cases to surgical repair (plugging) for severe, debilitating symptoms.

Understanding Superior Semicircular Canal Dehiscence Syndrome (SCDS)

Superior semicircular canal dehiscence (SCDS) is an inner ear disorder caused by a thinning or absence of the bone covering the superior semicircular canal. This bony defect creates a "third window" in the inner ear, allowing sound and pressure to travel incorrectly within the inner ear's fluid-filled canals. This abnormal pressure transmission is what leads to the unusual constellation of auditory and balance problems characteristic of SCDS.

While the exact cause is not fully understood, it is believed to be either a congenital defect present from birth or potentially triggered by head trauma or age-related bone thinning. The resulting symptoms can range from mild to debilitating, significantly impacting a person's quality of life.

Key Auditory Symptoms of Dehiscence Syndrome

The auditory symptoms of SCDS are often the most distinctive and bizarre, sometimes leading patients to believe they are imagining their condition.

Autophony and Bone Conduction Hyperacusis

Autophony is the abnormal hearing of one's own voice or other bodily sounds. Patients describe hearing their own voice as excessively loud, distorted, or echoing inside their head. Bone conduction hyperacusis is a related symptom where the patient hears internal noises that are usually undetectable, such as:

Their own heartbeat (pulsatile tinnitus)
The sound of their eyes moving or blinking
Joint or neck creaking noises
Chewing and other digestive sounds

Hyperacusis (Sound Sensitivity)

In addition to internal noises, many patients with SCDS experience hypersensitivity to external sounds, a condition known as hyperacusis. This can make everyday noises, like silverware clattering or a person's laugh, feel uncomfortably loud or painful. This can lead to patients avoiding social situations or wearing ear protection to cope.

Hearing Loss

SCDS can also cause hearing loss, typically affecting low-frequency sounds. This isn't a true sensorineural loss but a "pseudo-conductive hearing loss" resulting from the abnormal pressure dynamics in the inner ear. The low-frequency air-bone gap seen on audiograms is a key diagnostic clue for specialists.

Vestibular (Balance) Symptoms of SCDS

The balance-related symptoms are equally disruptive and can be triggered by specific actions or noises.

Vertigo and the Tullio Phenomenon

One of the hallmark symptoms is vertigo or dizziness triggered by loud noises, known as the Tullio phenomenon. For some, simple exposure to a loud sound can cause a sudden, brief spinning sensation. Pressure changes can also induce vertigo, such as those caused by:

Sneezing or coughing forcefully
Straining or heavy lifting
Scuba diving or flying

Oscillopsia

Oscillopsia is a visual disturbance where objects appear to be moving or vibrating when they are actually stationary. In SCDS, this can be triggered by either sound or pressure, and some patients even feel as if their surroundings are moving in sync with their heartbeat.

Chronic Disequilibrium and Unsteadiness

Many patients report a persistent feeling of unsteadiness or imbalance, which can be constant or come and go. This chronic disequilibrium can be exacerbated by physical activity, making exercise and even walking feel difficult.

Distinguishing SCDS from Other Conditions

SCDS symptoms can overlap with other inner ear disorders, making diagnosis challenging. Here is a comparison to help differentiate SCDS from other common conditions.


Feature	Superior Canal Dehiscence Syndrome (SCDS)	Meniere's Disease	Otosclerosis
Underlying Cause	Thinning or absence of bone over the superior semicircular canal, creating a "third window".	Excessive fluid buildup (endolymphatic hydrops) in the inner ear.	Abnormal bone remodeling in the middle ear, fixating the stapes bone.
Key Symptoms	Autophony, sound- or pressure-induced vertigo, low-frequency pseudo-conductive hearing loss.	Vertigo attacks, fluctuating hearing loss, ear fullness, and tinnitus.	Progressive conductive hearing loss, typically without autophony or pressure-induced vertigo.
Triggers	Loud noises, coughing, sneezing, straining, pressure changes.	Often unpredictable, but can be linked to diet or stress.	Progressive, not typically tied to specific sound or pressure triggers.
Diagnosis Aid	High-resolution temporal bone CT scan and Vestibular Evoked Myogenic Potentials (VEMP) test.	Audiogram and ruling out other conditions.	Audiogram showing specific conductive loss patterns, acoustic reflex testing.

Management and Treatment of SCDS

Diagnosis typically involves a combination of specialized hearing and balance tests, a detailed symptom history, and a high-resolution CT scan of the temporal bones.

Non-Surgical Management For those with mild symptoms, simply avoiding known triggers can offer significant relief. This might include wearing earplugs, avoiding loud environments, and refraining from heavy lifting or straining. Vestibular physical therapy can also help manage balance issues.

Surgical Treatment For more severe cases where symptoms are debilitating, surgical repair is often the most effective option. The goal of surgery is to close or cover the bony defect to restore normal inner ear mechanics.

Common surgical approaches include:

Canal Plugging: The surgeon plugs the superior semicircular canal with bone chips and soft tissue, effectively sealing the third window. This can be done via a middle cranial fossa approach (above the ear) or a transmastoid approach (behind the ear).
Round Window Reinforcement: A less invasive procedure that reinforces the round window to dampen the pressure abnormalities.

Post-surgery, most patients report significant and lasting improvement, especially in auditory symptoms.

Conclusion: Navigating Symptoms and Seeking Help

If you are experiencing a confusing combination of balance issues and unusual hearing phenomena, including sensitivity to sound, dizziness triggered by noise, or hearing internal bodily sounds, it is crucial to consult with a specialist. As we have seen, what are the symptoms of dehiscence syndrome can be quite specific, allowing experienced otologists and neurotologists to provide an accurate diagnosis. A correct diagnosis is the first step toward effective management and can alleviate the stress and anxiety that often accompany these strange symptoms. Understanding your condition empowers you to seek the right treatment, whether through lifestyle changes or surgical intervention, and ultimately reclaim your quality of life.

For more information on inner ear disorders, you can visit the American Academy of Otolaryngology–Head and Neck Surgery.

Frequently Asked Questions

The primary cause of dehiscence syndrome is a defect—either a thinning or a complete absence of the bone—that covers the superior semicircular canal in the inner ear. This defect is thought to be present from birth but may be triggered by head trauma or bone loss later in life.

Yes, dehiscence syndrome can cause hearing problems. It commonly results in low-frequency hearing loss, along with a heightened sensitivity to both internal and external sounds, including autophony and pulsatile tinnitus.

Autophony is a specific symptom of dehiscence syndrome where a person hears their own voice, breathing, or other internal body sounds as unusually loud or distorted. This occurs because the bony defect allows these sounds to enter the inner ear abnormally.

The Tullio phenomenon is a balance disturbance unique to SCDS where exposure to loud sounds causes a sensation of vertigo or dizziness. It happens because the sound pressure incorrectly stimulates the inner ear's balance system.

Diagnosis of dehiscence syndrome typically involves several steps: a detailed patient history, a high-resolution CT scan of the temporal bones to visualize the defect, and specialized vestibular testing, such as VEMP tests, to confirm the abnormal pressure transmission.

No, surgery is not necessary for all cases. For patients with mild or manageable symptoms, conservative management, such as avoiding triggers and wearing ear protection, is often recommended. Surgery is generally reserved for severe, debilitating cases.

While both conditions affect the inner ear, SCDS is caused by a structural bony defect, whereas Meniere's is caused by fluid buildup. SCDS often presents with specific auditory symptoms like autophony and pressure-induced vertigo, which are less typical of Meniere's.