title: Inner ear dysplasia is common in children with Down syndrome (trisomy 21).
abstract: OBJECTIVE
  Middle and external ear anomalies are well recognized in Down syndrome (DS, trisomy 21). Inner ear anomalies are much less frequently described. This study reviews inner ear morphology on imaging to determine the prevalence of cochlear and vestibular anomalies in children with DS.
  
  
  METHODS
  The authors conducted a retrospective review of imaging features of (DS) inner ear structures.
  
  
  METHODS
  Fifty-nine sequential patients with DS with imaging of the inner ear were identified by a radiology report text search program. Quantitative biometric assessment of the inner ear was performed on patients with high-resolution computed tomography or magnetic resonance images of the petrous bone. Petrous imaging was performed for evaluation of inflammatory disease or hearing loss. Spinal imaging, which included petrous views, was performed in most cases to exclude C1 to 2 dislocation, a potential complication of DS. Measurements were compared with normative data.
  
  
  RESULTS
  Inner ear dysplasia is much more common in DS than previously reported. Inner ear structures are universally hypoplastic. Vestibular malformations are particularly common and a small bony island of the lateral semicircular canal (<3 mm in diameter) appears highly typical. Additional findings in some patients were persistent lateral semicircular anlage with fusion of the lateral semicircular canal and vestibule into a single cavity, vestibular aqueduct and endolymphatic sac fossa enlargement, cochlear nerve canal hypoplasia, and stenosis or duplication of the internal auditory canal. Stenosis of the external meatus, poor mastoid pneumatization, middle ear and mastoid opacification, and cholesteatoma were common, as expected.
authors.affiliation: Department of Diagnostic Imaging, Division of Neuroradiology, The Hospital for Sick Children and the University of Toronto, Toronto, Ontario, Canada. susan.blaser@sickkids.ca
authors.forename: Susan
authors.initials: S
authors.lastname: Blaser
authors.forename: Evan J
authors.initials: EJ
authors.lastname: Propst
authors.forename: Daniel
authors.initials: D
authors.lastname: Martin
authors.forename: Annette
authors.initials: A
authors.lastname: Feigenbaum
authors.forename: Adrian L
authors.initials: AL
authors.lastname: James
authors.forename: Patrick
authors.initials: P
authors.lastname: Shannon
authors.forename: Blake C
authors.initials: BC
authors.lastname: Papsin
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003051:Cochlea / Q000002:abnormalities*; D004108:Dilatation, Pathologic; D004314:Down Syndrome / Q000150:complications* / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012665:Semicircular Canals / Q000473:pathology; D013701:Temporal Bone / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D014722:Vestibule, Labyrinth / Q000002:abnormalities* / Q000473:pathology