후반고리관만 침범한 급성말초전정병증 환자 1예

Abstract

Down-beat nystagmus in peripheral vestibulopathy may rarely occur in selective involvement of inferior division. Diagnosis of isolated inferior vestibular neuritis is based on torsional down-beating spontaneous nystagmus, abnormal head-impulse test for the posterior semicircular canal, and abnormal cervical vestibular evoked myogenic potentials (cVEMPs) with normal bithermal caloric tests and ocular vestibular evoked myogenic potentials (oVEMPs). Herein we report a 50-year-old male patient with spontaneous down-beat nystagmus who demonstrated vestibular dysfunction involving only the posterior semicircular canal. The patient showed normal results in the bithermal caloric test, the oVEMPs and cVEMPs test. Video head impulse test showed decreased gain and corrective saccades only in the posterior semicircular canal. This case is significant in showing that peripheral dizziness with spontaneous down-beating nystagmus can occur as a result of an abnormality involving only a single semicircular canal.