الفهرس 
Chapter I: Anatomical Considerations for CIOnly 14 pages are availabe for public view
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Abstract
Several authors have investigated the effect of cochlear
implantation on the vestibular system, with high variability in results.
The aim of this study was to study to evaluate the effect of cochlear
implantation on the inferior vestibular nerve function and to examine
the correlation between the approaches of cochlear implant and
vestibular insult (if any).
The study included 20 patients with severe to profound
sensorineural hearing loss who underwent cochlear implantation
surgery 11 of them by posterior tympanotomy approach and 9 of them
by transcanal approach. Evaluation of the vestibular function was
done before and after the surgery by cVEMP responses.
The most common etiology of HL among study group was the
heredofamilial cause (35%) and unknown etiology representing (35%)
followed by postfebrile (20%). cVEMP showed abnormal or absent
responses in 7/20(35%) preoperatively.
Our study results revealed that, 9 patients out of 13 patients
(69%) lost c VEMP response postoperatively.
Our results showed no significant difference between the two
different surgical approaches used during the study, these results also
showed that c VEMP was normal postoperatively when Round
window insertion technique was used (80%) while there was loss of
c VEMP response postoperatively in all patients when insertion of
the electrodes was done through bony cochleostomy.