Cochlear modiolus and lateral semicircular canal in sudden deafness.

Area of Science:

• Otolaryngology
• Radiology
• Developmental Biology

Background:

• Sudden deafness (SD) is an idiopathic condition often associated with inner ear dysfunction.
• Understanding the morphological characteristics of the inner ear in SD is crucial for elucidating its pathophysiology.
• Magnetic resonance imaging (MRI) offers a non-invasive method to assess inner ear structures.

Purpose of the Study:

• To quantitatively analyze cochlear and lateral semicircular canal (LSCC) morphologies in sudden deafness patients using MRI.
• To investigate the relationship between inner ear morphology and clinical symptoms, such as vertigo, in sudden deafness.
• To compare inner ear dimensions between sudden deafness patients and healthy controls.

Main Methods:

• A case-control study involving 26 unilateral sudden deafness patients with vertigo, 26 without vertigo, and 26 matched controls.
• MRI scans were used to measure the areas of cochlear modioli and LSCCs.
• The ratio of the LSCC fluid-filled area to the total LSCC area was calculated to assess dysplasia.

Main Results:

• SD ears exhibited significantly smaller cochlear modiolus areas (4.1±0.2 mm²) compared to controls (4.3±0.4 mm²).
• The inner area of the LSCC was significantly reduced in SD ears (6.9±1.7 mm²) versus controls (9.1±1.8 mm²).
• The fluid-filled area of the inner ear was significantly larger in SD patients than in controls.

Conclusions:

• Inner ear morphology in sudden deafness differs significantly from controls, characterized by larger fluid-filled spaces.
• Reduced cochlear modiolus and LSCC areas may indicate insufficient inner ear maturation in some sudden deafness cases.
• No significant morphological differences were observed between affected and contralateral sides or between SD patients with or without vertigo.