A 46-year-old female with profound sensorineural hearing loss in her left ear from childhood developed tinnitus and fluctuating hearing loss on the right side 8 years ago.Four years later,paroxysmal episodes of rotatory vertigo occurred with gradually increased frequency,lasting from half an hour to 2 hours and accompanied with nausea and vomiting.Audiometric test revealed severe sensorineural hearing loss in both of her ears.The tympanograms showed type A on both sides.The threshold of auditory brainstem response was 97 dBnHL in her right ear while no waves could be educed on her left side.Weakened right-sided vestibular function was confirmed on caloric testing and vestibular-evoked myogenic potential.A normal cochlear morphology and clearness cerebellopontine angle were shown in the MR imaging scan.She was diagnosed with Delayed Endolymphatic Hydrops.