10/08/2026
🔔🎧Dizzy, off-balance, or blurred/double vision when exposed to loud sound or pressure?
🪟👂Consider a �a third window disorder, such as a perilymphatic fistula (PLF) or superior semicircular canal dehiscence (SSCD or SCD). SSCD is caused by missing bone over the superior aspect of a semicircular canal, creating a third “mobile window” in the bony labyrinth.
🌊🏋️This bony inner ear thinning -> opening may not reveal itself until middle age (~45 years old) after a secondary event disrupts the bone: physical trauma, a significant change in intracranial pressure (heavy lifting, severe coughing, childbirth etc.), or a barometric pressure shift while scuba diving.
🧩🛎️Test for Tullio’s phenomenon (sound-induced vertigo, disequilibrium, or involuntary eye movements):
1. Place your patient in a seated position with infrared video goggles on.
2. Introduce a loud sound or pure tone (start at lower frequencies like 125 Hz and ~60 dB, then scaling up in pitch and intensity).
3. Observe for nystagmus and symptoms timed synchronously with the sound.
4. Repeat on the other ear.
🎸This patient showed a response at 3000 Hz (high pitch) at 110 dB (a loudness level equivalent to a rock concert).
🎯 🚀High-resolution CT scan of the temporal bone showed Bilateral SSCD.
👁️ So, what direction of nystagmus might we see in patients with SSCD, and what could that indicate?
📚The textbook answer for SSCD is downbeat, torsional nystagmus away from affected side... but real-life patients can be more complex.
⏭️ In this video, when sound was introduced to the right ear, a right-beating horizontal nystagmus occurred in sync with the sound.
🤔 In this case, there may have been so much energy moving through the ears that the vertical components of nystagmus from the anterior and posterior canals on both sides canceled each other out. The horizontal component could not be cancelled out.
🏆 Video credit and shared with permission: Dr. Arun Gadre, MD (neurotology) and Dr. Jeff Walter, PT, DPT, NCS. Thanks to collaborators Sara & Sydney I Vestibular Physical Therapists and Balancing Act Rehab | Neuro + Vertigo Therapists & Educators too!
🎁 Get a free Dizziness Handicap Inventory (DHI) resource at dz.
