Third Window Syndrome: Symptoms, Diagnosis & Treatment

Third window syndrome describes a group of vestibular and auditory symptoms that result from a leakage of pressure and/or fluid from the inner ear structures, due to an abnormal communication.

What causes third window syndrome?

The symptoms are caused by the presence of an abnormal third mobile window in the bony labyrinth of the inner ear. Normally, the inner ear has only two mobile windows: the oval and the round window. This pathological opening disrupts the normal biomechanics of the inner ear.

Third window syndrome is most commonly due to abnormalities that cause dehiscence (absence) or near-dehiscence (thinning) of bony sections lying superior to the canal.

Types of third window syndrome

A disruption in pressure due to a weakness or opening in the tissues or bones of the inner ear can cause third window syndrome. These may occur:

• At blood supply or nerve attachment sites to the hearing or balance organs.
• In the bones connecting the middle ear to the inner ear.
• In the openings connecting the hearing and balance organ to their fluid supply.

Aetiology

The cause of the disruption may be:

• Genetic tendency.
• Differences in skull shape and organs.
• Head trauma and surgery.
• Barotrauma or straining.
• Tumors or infections.
• Elevated intracranial pressure.

Signs and symptoms of third window syndrome

Symptoms may include:

• Sound-induced dizziness.
• Dizziness from physical strain, like weightlifting, coughing, sneezing or blowing the nose.
• Difficulty in maintaining a steady gaze when hearing loud sounds or when experiencing physical strain.
• Autophony (hearing your own voice louder than normal).
• Hearing other internal noises abnormally, such as heartbeat, eye movement or blinking.
• Mixed hearing loss.
• Sensitivity to loud sounds.
• Tinnitus.

Diagnosis of third window syndrome

The diagnosis is determined by a specialized ENT-Neurootologist at EYiasis, through a complete medical history, physical examination and an audiogram.

Diagnostic tests

Further tests may be carried out at the EYiasis Vertigo and Neuro-otology Lab:

• Tullio testing: evaluation for nystagmus while putting sound in the ear.
• Fistula testing: evaluation for nystagmus or imbalance with pressure applied to the ear drum.
• Valsalva testing: evaluation for nystagmus when the patient strains.
• High-resolution CT or vestibular-evoked myogenic potential (VEMP) testing, when required.

Management and treatment of third window syndrome

• Conservative management: lifestyle changes, such as avoiding triggers including loud sounds and physical strain, may be implemented to tolerate symptoms and reduce more severe effects. Treating any coexisting or exacerbating conditions, such as migraine or vestibular migraine, may also improve the symptoms.
• Surgical repair: it may sometimes be recommended if the patient has more severe and intolerable symptoms.

If loud sounds, coughing or physical effort make you dizzy, contact EYiasis for a full neuro-otological evaluation.

References

1. Iversen MM, Rabbitt RD. Biomechanics of Third Window Syndrome. Front Neurol. 2020;11:891.
2. Lazarou I, Sideris G, Papadimitriou N, Delides A, Korres G. Third Window Syndrome: An Up-to-Date Systematic Review of Causes, Diagnosis, and Treatment. J Audiol Otol. 2025 Apr;29(2):86-94.
3. Suzuki M, Ota Y, Takanami T, Yoshino R, Masuda H. Superior canal dehiscence syndrome: a review. Auris Nasus Larynx. 2024;51:113-9.
4. Basura GJ, Cronin SJ, Heidenreich KD. Tullio phenomenon in superior semicircular canal dehiscence syndrome. Neurology. 2014;82:1010.