Cochlear modiolus and lateral semicircular canal in sudden deafness

Abstract

Conclusion: This study demonstrated that precise analysis shows that the inner ear shape in sudden deafness (SD) is different from that in controls in that the fluid-filled area of SD labyrinths is significantly larger than that of controls. Reduced cochlear modiolus area and inner area of the lateral semicircular canal (LSCC) may be associated with insufficient maturation of the inner ear.

Objective: The aim of this study was to quantify the morphologies of the cochlea and LSCC using magnetic resonance imaging (MRI) and to evaluate their relationships with clinical symptoms in SD.

Subjects and methods: Twenty-six unilateral SD patients with vertigo, 26 unilateral SD patients without vertigo and a matched control group without hearing loss were studied. The areas of cochlear modioli and LSCCs were traced on the MRI console and compared between SD patients with or without vertigo and control subjects. The ratio of the LSCC fluid-filled area to the total LSCC area was used to index the degree of dysplasia.

Results: The cochlear modiolus area was significantly less in SD ears (4.1+/-0.2 mm2) than in controls (4.3+/-0.4 mm2). The LSCC inner area was significantly less in SD ears (6.9+/-1.7 mm2) than in controls (9.1+/-1.8 mm2). These results suggest that the fluid-filled area of SD labyrinths is significantly larger than controls. Morphology did not differ between affected and contralateral sides or between ears with or without vertigo in SD patients.