الفهرس 
Introduction and rationale and aims of workOnly 14 pages are availabe for public view
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Abstract
Our study was performed on 35 ANSD patients, 32 SNHL patients and 15 control children. The aims of the current study were to record and describe VEMP in children with ANSD, to compare VEMP findings in ANSD children to those in children with profound non-neuropathy SNHL, and to determine if the VEMP can separate presynaptic site of lesion from the postsynaptic site of lesion in ANSD.
Results of our study showed that:
The vast majority of ANSD children (88% of ears) had intact and normal VEMP response. Furthermore, No significant difference was found between ANSD children and normal children as regards P1-N1 amplitude, P1 latency, N1 latency and AR. Results reflects normal saccular function along with normally functioning inferior vestibular nerve and higher central connections, which are responsible for VEMP response in the majority of ANSD children.
The minority (12% of ears) had an absent VEMP response. All ANSD children with absent VEMP response were males while none of female children had absent VEMP. This can be explained by a genetic origin of X-linked inheritance pattern of ANSD.
No difference between the ANSD without risk factors and with risk factors as regards the percentages of children having intact or absent VEMP response, P1-N1 amplitude, AR, P1 or N1 latency of VEMP response. Such results reflect that risk factors that are known to affect the auditory nerve and the higher auditory nervous system do not affect the inferior vestibular nerve. These results support the choice of cochlear implantation in cases of ANSD even in the presence of risk factors as there will be no fear of bilateral saccular dysfunction in the case saccular damage occurred in the surgery side as a result of the surgical procedure.
While the vast majority of ANSD children had intact and normal VEMP response, less than half of the ears (47% of ears) of non- neuropathy SNHL children had intact VEMP response and 53% of ears had absent VEMP response. Such difference in the VEMP results reflects different pathological site (s) and pathological mechanisms between the regular SNHL and ANSD. While the pathology involves the saccule in the majority of cases of SNHL, the pathology beyond ANSD in children with pre-lingual onset is limited to the auditory system in the vast majority of cases and spares the saccule.
Overall, our study provided evaluation of the saccule and the inferior vestibular nerve in ANSD children. Similarly; the other parts of the vestibular system can be evaluated by other procedures. The oVEMP can evaluate the utricle and superior vestibular nerve and the video head thrust can evaluate the three semicircular canals.