A series of 29 patients with the Arnold-Chiari malformation who had signs and symptoms related to the auditory and vestibular systems are analyzed, and four illustrative case reports are detailed. Although no consistent pattern emerged, these abnormalities may simulate other lesions, including acoustic neuromas. This disease should be considered in the neuro-otologic differential diagnosis. Hypotheses on the pathogenesis of the auditory and vestibular dysfunction include further stretching of the congenitally elongated nerves, bending of the eighth cranial nerve over the bony edge of the porus acusticus, and compression of brain-stem nuclei by displaced cerebellar tonsils.
Rydell RE, Pulec JL. Arnold-Chiari MalformationNeuro-otologic Symptoms. Arch Otolaryngol. 1971;94(1):8–12. doi:10.1001/archotol.1971.00770070044002