Brain Stem and Inner Ear Abnormalities in Children with Auditory Neuropathy Spectrum Disorder and Cochlear Nerve Deficiency

Inner ear and brain abnormalities in a 2-year-old girl with ANSD and bilateral CND. A, Axial CISS images through the bilateral inner ears and IACs. The left IAC is stenotic, particularly at the level of the porus acousticus (arrow), while the right IAC is normal in caliber. Both cochleae are isolated and dysplastic, with truncated apical turns, and the right modiolus is deficient. B, Midsagittal T1-weighted image demonstrates callosal agenesis, pontine hypoplasia, and inferior vermian hypoplasia. There is a prominent ventral cleft at the level of the pontomedullary junction. C, Axial T2-weighted image through the lateral ventricles demonstrates ventriculomegaly and diffuse pachygyria with relatively few sulci.

Inner ear and brain abnormalities in patients with bilateral CND and pontine segmental cap dysplasia. A, Axial CISS images through the inner ears in a 1-year-old girl. Both cochleae demonstrate deficient modioli and incomplete partitioning. The BCNCs are also small and possibly atretic. B, Sagittal midline T1-weighted image in a 2-year-old boy demonstrates characteristic pontine hypoplasia and an abnormal exophytic masslike band along the dorsal superior surface of the pons (white arrow). The vermis is also hypoplastic inferiorly. C, Axial T2-weighted image at the level of the MCPs in the same patient as A. The pons and MCPs are small, and there is a transversely oriented band along the dorsal pons, separated from the remainder of the pons by a hypointense horizontal cleft (black arrowheads).