How does cochlear implantation affect five vestibular end-organ functions and dizziness?
OBJECTIVE
To evaluate all five vestibular end-organ functions (lateral, anterior, posterior semicircular canal, utricule, and saccule) and to investigate the relationship between Dizziness Handicap Inventory (DHI) and vestibular functions prior to CI (cochlear implantation) and at postoperative day 3 and month 3.


METHODS
A total of 42 patients (age 16-70years) with normal vestibular functions preoperatively and undergoing unilateral CI were included in this prospective descriptive study. Video head impulse test (vHIT) for three semicircular canal (SSC) functions, ocular vestibular-evoked myogenic potential (oVEMP) for utricule function, cervical vestibular-evoked myogenic potential (cVEMP) for saccule function and DHI for subjective vertigo symptoms were performed prior to CI and at postoperative day 3 and month 3.


RESULTS
There was a significant impairment of vestibular function in 12 patients (28.5%) on the implantation side and significant DHI increase was observed in 13 of 42 (30.9%) patients at postoperative day 3 after CI (p<0.05). We found SSC dysfunction in 7 patients (16,6%) who underwent observation with vHIT, saccule dysfunction in 8 patients (19%) with cVEMP and utricule dysfunction in 5 patients (11.9%) with oVEMP on the operated side 3days after surgery (p<0.05). Posterior SSC functions (5 patients) were more affected than lateral SSC functions (3 patients). At postoperative month 3, six patients (14.2%) still had deteriorating results in the objective tests and significant DHI increase was continued in 4 (9.5%) patients (p<0.05). The deterioration in vHIT continued in only 1 (2.3%) patient (p>0.05). The deterioration in cVEMP continued in 5 (11.9%) patients (p<0.05). The deterioration in oVEMP continued in 2 (4.7%) patients (p>0.05). There was a significant correlation between DHI and objective vestibular tests both in the early and late postoperative period (r=0.795; p<0.05).


CONCLUSION
Our study showed that both canal and otolith functions can be damaged after CI especially in the early postoperative period. Surprisingly, posterior SSC functions were more affected than lateral SSC. Therefore, a gold standard vestibular test battery that can evaluate each of three SSC canals and two otoliths functions is essential. Since a single vestibular test for this purpose is not available, we recommend the use of the three available vestibular tests together. This test battery, which is capable of evaluating five vestibular end-organ functions in preoperative and postoperative vestibular evaluations, can provide more accurate results not only for CI but also for most otologic surgeries.
['Dagkiran|Muhammed|M|', 'Tuncer|Ulku|U|', 'Surmelioglu|Ozgur|O|', 'Tarkan|Ozgur|O|', 'Ozdemir|Suleyman|S|', 'Cetik|Fikret|F|', 'Kiroglu|Mete|M|']
D000293:Adolescent D000328:Adult D000368:Aged D019929:Cochlear Implantation D004244:Dizziness D005260:Female D064087:Head Impulse Test D006319:Hearing Loss, Sensorineural D006801:Humans D008297:Male D008875:Middle Aged D011183:Postoperative Complications D011446:Prospective Studies D012444:Saccule and Utricle D012665:Semicircular Canals D011795:Surveys and Questionnaires D014717:Vertigo D015837:Vestibular Diseases D058585:Vestibular Evoked Myogenic Potentials D055815:Young Adult
Cochlear implantation Five vestibular end-organ function Dizziness handicap inventory Video head impulse test Cervical vestibular-evoked myogenic potentials Oculer vestibular-evoked myogenic potentials