الفهرس 
Introduction and rationaleOnly 14 pages are availabe for public view
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Abstract
The outcome of CI was previously investigated in a considerable number of researches. Those studies revealed positive outcome as regards auditory and speech perceptual skills. However, controversy was present as regards some of surgical complications, timing of CI and more recently electrode impedance instability that may further affect consistent auditory benefit.
The aim of this work was to investigate the outcome of CI in such cases as regards postoperative auditory and speech perceptual skills. The second aim was to investigate postoperative stability of CI through postoperative checking stability of EI and ECAP.
The study included 48 subjects aged from four to 28 years underwent CI divided as follow: eight subjects with isolated EVA, 16 subjects with EVA associated with other inner ear malformations. The outcome of CI in those subjects was compared to CI outcome in 24 subjects without any inner ear malformations.
The protocol of the study included: preoperative and intraoperative data collection. Postoperative assessment included: audiological assessment through MAIS questionnaire, aided hearing thresholds, aided SRT and aided speech discrimination tests. Speech and language assessment was done through Arabic language age and aided phoneme perception test. Serial electrode impedance measures were recorded and pattern of EI changes over time was investigated in the studied groups. Postoperative ECAP characteristics and stability after CI were also investigated.
The resulting data revealed that outcome of CI in isolated EVA patients regarding auditory skills as well as speech perceptual abilities was comparable to that of the control group and both had a statistically significant better outcome than that of EVA-IP II group. Changes in EI overtime in isolated EVA group didn’t revealed major fluctuations. ECAP characteristics suggested that EVA subjects might have better neuronal survival than in EVA –IP II subjects and even than some subjects of the control group.
This study recommends that CI could be considered safely in EVA subjects with severe to profound hearing losses. Subjects with less severe hearing losses should be implanted if hearing fluctuations interfere with consistent auditory input and speech perceptual abilities.