Bilateral semicircular canal aplasia with near-normal cochlear development. Two case reports

Ann Otol Rhinol Laryngol. 1990 Dec;99(12):957-9. doi: 10.1177/000348949009901205.


Congenital malformations of the vestibular labyrinth (pars superior) are rare. We present two patients with computed tomographic findings of bilateral semicircular canal aplasia with normal or near-normal cochleas. Initial bone conduction thresholds were within normal limits, although both patients had significant conductive hearing losses due to congenital middle ear malformations. Bithermal caloric responses were absent in both. To our knowledge these are the first reports of vestibular aplasia concomitant with normal or near-normal cochlear development. These findings conflict with conventional hypotheses that state that inner ear malformations result from arrested development during the normal stages of inner ear embryogenesis.

Publication types

  • Case Reports

MeSH terms

  • Adult
  • Cochlea / abnormalities
  • Cochlea / diagnostic imaging*
  • Ear Ossicles / abnormalities
  • Female
  • Hearing Loss, Bilateral / congenital
  • Hearing Loss, Bilateral / diagnostic imaging
  • Hearing Loss, Conductive / congenital
  • Hearing Loss, Conductive / diagnostic imaging
  • Humans
  • Semicircular Canals / abnormalities*
  • Semicircular Canals / diagnostic imaging
  • Tomography, X-Ray Computed