Influence of cochlear implantation on peripheral vestibular receptor function.
OBJECTIVE
The objectives of this study were 1) to assess the influence of a cochlear implantation on peripheral vestibular receptor function in the inner ear in the implant and in the nonimplant side, and 2) to analyze a possible correlation with resulting vertigo symptoms.


METHODS
Prospective clinical study.


METHODS
Cochlear implant center at tertiary referral hospital.


METHODS
A total of 32 patients, aged 15 to 83 years, undergoing cochlear implantation were assessed pre- and postoperatively for caloric horizontal semicircular canal response and vestibular-evoked myogenic potentials of the sacculus, and postoperatively for subjective vertigo symptoms. Patients with vertigo were compared with patients without symptoms with regard to the findings of the vestibular function tests.


RESULTS
Cochlear implantation represents a significant risk factor for horizontal semicircular canal impairment (P < 0.001) and sacculus impairment (P = 0.047) in the implanted ear. In eight of 16 patients with preoperatively preserved caloric response, this response was decreased postoperatively. Before surgery, 14 of 30 patients had regular vestibular-evoked myogenic responses. Two months after implantation, six patients had a new loss and another six showed depression of sacculus function on vestibular-evoked myogenic potentials testing. The impaired vestibular function did not correlate with vertigo symptoms. Function on the contralateral side remains unaffected (P > 0.05).


CONCLUSIONS
Cochlear implantation is a relevant risk factor for damage of peripheral vestibular receptor function. Therefore, preservation not only of residual hearing function but also of vestibular function should be aimed for, by using minimally invasive surgical techniques.
Krause
Eike
E
Department of Oto-Rhino-Laryngology, Head and Neck Surgery, Ludwig-Maximilians-University, Munich, Germany. Eike.Krause@med.uni-muenchen.de
Louza
Julia P R
JP
Wechtenbruch
Juliane
J
Gürkov
Robert
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019929:Cochlear Implantation / Q000009:adverse effects*; D005071:Evoked Potentials; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology; D011446:Prospective Studies; D012444:Saccule and Utricle / Q000502:physiology; D012665:Semicircular Canals / Q000293:injuries*; D014717:Vertigo / Q000453:epidemiology / Q000209:etiology