Anatomic Malformations of the Middle and Inner Ear in 22q11.2 Deletion Syndrome: Case Series and Literature Review

A, Axial CT image of the left mastoid shows a normal stapes superstructure for comparison with B. B, Axial CT image of the right mastoid shows a dense, thick stapes superstructure. The pure tone audiogram of this patient is shown in Fig 5B. The mastoid bones shown in A and B do not belong to the same patient.

A, Axial CT image of the right mastoid shows an incomplete partition type II of the cochlea. The basal turn (BT) of the cochlea is intact; the apical and middle turn (A/M) seem confluent. B, A pure tone audiogram of the same ear shows normal hearing. The circle indicates an unmasked air-conduction threshold; the bracket, a masked bone-conduction threshold.

A, Axial CT image of left mastoid bone shows the lateral semicircular canal with a small bony island. B, A pure tone audiogram of the same ear shows a mild conductive hearing loss. The x indicates an unmasked air-conduction threshold; the bracket, a masked bone-conduction threshold.

A, Axial CT image of the right mastoid bone. The bony island of the lateral semicircular canal is missing, and the canal and vestibule are composed of a single cavity (SC). B, A pure tone audiogram of the same ear shows conductive hearing loss, more pronounced in the low frequencies. The circle indicates an unmasked air-conduction threshold; the bracket, a masked bone-conduction threshold.