Assessment Of Vestibular Function Before And After Cochlear Implantation In Adults

ObjectiveIn this study,we evaluated the vestibular function of adult cochlear implants before and after surgery to evaluate the vestibular function in adults with sensorineural hearing loss by vestibular function examination and Dizziness Handicap Inventory.Through the assessment of vestibular function,Its outcome provides a basis for the safety of cochlear implants,especially bilateral implants.MethodsThe selected 50 cases of severe bilateral sensorineural hearing loss adults were documented between October 2016 and October 2017 in Guangdong general hospital.There are 28 males and 22 females,ranged from 18 to 69 years,with an average age of 35.1 ± 15.8 years.10 cases underwent bilateral cochlear implantation and 40 cases underwent unilateral implant(30 right ear implanted,10 left ear implanted).Using the cervical vestibular evoked myogenic potential(cVEMP),ocular vestibular evoked myogenic potential(oVEMP),caloric test and video head impulse test(vHIT)to assess the function of vestibular.Vertigo symptoms was collected and the patients were evaluated for Dizziness Handicap Inventory(DHI).The vestibular evoked myogenic potential was positive when the waveform loss.The caloric test was positive when UW>25%or SPV mean<6°/s,vHIT was abnormal when vHIT-G(LC)<0.8,vHIT-G(AC.PC)<0.7.ResultsThe positive rates of cVEMP,oVEMP,caloric test and vHIT(LC/AC/PC)in 50 patients were 40%,36%,42.5%,45%/40%/30%.No significant difference between the surgical ear and non-surgical ear.The positive rates of cVEMP and caloric test in one week to six months after operation were significantly different from the preoperative values,while the differences between oVEMP and preoperative positive rates in one year and six months after operation were still statistically significant.vHIT-G has no significant difference before and after implant.Postoperative vertigo occurred in 12 cases(24%).The incidence of vertigo(30%)in bilateral cochlear implantation group was higher than that in unilateral implantation group(22.5%).The symptoms of vertigo patients were relieved within six months after operation,and the DHI score increased one week after operation compared with that before operation,and the difference was statistically significant.There was no significant difference between preoperative and postoperative one month to one year.Conclusions1.Adult patients with sensorineural hearing loss have vary degrees of vestibular function impaired,and related with their causes of deafness.2.Cochlear implants may have impaired vestibular function,manifested as abnormalities of vestibular function examination and dizziness symptoms,and the probability of damage to vestibular end-organ was followed by utricle,saccule and semicircular canal.3.The impaired vestibular function after cochlear implantation showed a trend of recovery in one year after surgery.The function of vestibular function was significantly impaired after cochlear implantation for one week,and there was a tendency of recovery.Among them,utricle and senmicircular canals returned to normal after six months,and the saccule returned to normal one year after surgery.4.The effect of cochlear surgery on the function of the semicircular canal in the low frequency region was significantly lower than that in the high frequency area.5.Compared with unilateral cochlear implant patients,the risk of dizziness after bilateral cochlear implant surgery is higher.