title: Vestibular dysfunction after cochlear implantation.
abstract: OBJECTIVE
  To determine the prevalence, symptom characteristics, and potential risk factors for vestibular symptoms after cochlear implantation.
  
  
  METHODS
  Case-control study design embedded within an ongoing cohort of patients undergoing implantation.
  
  
  METHODS
  Academic medical center cochlear implant research program funded by the National Institutes of Health.
  
  
  METHODS
  Seventy five eligible consecutive patients undergoing cochlear implantation.
  
  
  METHODS
  Medical record review.
  
  
  METHODS
  Recorded symptoms of vestibular symptoms after cochlear implantation. Subjects with vestibular symptoms were considered case subjects; those without vestibular symptoms were considered control subjects.
  
  
  RESULTS
  Twenty-nine of 75 (39%) patients experienced dizziness postoperatively. Four patients experienced a single, transient acute vertigo attack occurring less than 24 hours after surgery. The majority, 25 patients, experienced delayed, episodic onset of vertigo. The median (interquartile range) time of delayed onset was 74 (26-377) days after implantation. Delayed dizziness manifested as spontaneous episodic or positional vertigo. Preoperative dizziness, age at implantation, and age at onset of hearing loss were significantly greater in the dizzy group. Preoperative electronystagmography did not differentiate between groups.
  
  
  CONCLUSIONS
  Thirty-nine percent (29/75) of subjects with implants were dizzy after implantation. The majority of subjects experienced dizziness in a delayed episodic fashion. Dizziness was not related to implant activation. It seemed that delayed dizziness was not related to immediate surgical intervention but could result from chronic changes occurring in the inner ear; there was some suggestion this could take the form of endolymphatic hydrops.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, Campus Box 8115, 660 S. Euclid Ave. St. Louis, MO 63110, USA.
authors.forename: Manuela
authors.initials: M
authors.lastname: Fina
authors.forename: Margaret
authors.initials: M
authors.lastname: Skinner
authors.forename: Joel A
authors.initials: JA
authors.lastname: Goebel
authors.forename: Jay F
authors.initials: JF
authors.lastname: Piccirillo
authors.forename: J Gail
authors.initials: JG
authors.lastname: Neely
authors.forename: Owen
authors.initials: O
authors.lastname: Black
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001309:Auditory Threshold / Q000502:physiology; D016022:Case-Control Studies; D019929:Cochlear Implantation / Q000295:instrumentation; D015331:Cohort Studies; D004584:Electronystagmography; D018159:Endolymphatic Hydrops / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D013069:Speech Reception Threshold Test; D014717:Vertigo / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D014722:Vestibule, Labyrinth / Q000503:physiopathology*