[Otoneurologic symptoms associated with Arnold-Chiari syndrome type I]

This study presents two cases of Arnold-Chiari malformation type I. In a 26-year old man, right side deafness and left side sensorineural hearing loss at high frequencies occurred. Another patient, a 48-year old man also complained of sensorineural hearing loss and dizziness, that appeared a year and half ago. In addition, this patient had episodes of vertigo with nausea and vomit that occurred about one year before main symptoms. In both patients ENT examinations were performed as well as an audiological diagnostic battery including tonal- and impedance-audiometry, auditory brainstem responses, distortion product otoacoustic emissions and electroencephalography. Magnetic resonance imaging (MRI) showed pathological changes in the cerebello-pontine angle region that allowed diagnosing Arnold-Chiari malformation in both cases. Additionally, angio-MRI performed in patient with right side deafness revealed cochleovestibular nerve compression syndrome on the same side. Presumably, both anomalies occurring simultaneously in this patient might be responsible for deafness in the right ear, instead of mild or moderate hearing loss and tinnitus usually expected according to the literature. The paper presented two cases of Arnold-Chiari malformation with co-existing cochleovestibular nerve compression syndrome in one case. The importance of both audiological diagnostic battery and MRI in diagnostic procedures of this malformation has been demonstrated.