VEMP results of unilateral cochlear implant user with inner ear malformation: Preliminary results.

Objective: To evaluate vestibular evoked myogenic potentials (VEMP) results of unilateral cochlear implant users with inner ear malformations. Method: VEMP is a short latency myogenic response recorded with surface electrodes placed over muscles. VEMP response could be recorded even in subjects with severe to profound hearing loss and this reveals intact vestibular organs. However, it is complicated that what happens in case of inner ear malformations. In the current study, 10 unilateral cochlear implant users with inner ear malformations were included. These subjects were selected randomly from institutional ear malformations database. Both cervical VEMP (cVEMP) and ocular VEMP (oVEMP) was applied for all subjects. Results: Age range was in between 7 years and 6 months and 40 years with 20,7 mean. All subjects had different cochleaovestibular malformations and in same subject both ear also had different malformations. 9 subjects had right CI and 1 subject left CI. All subjects had bilateral normal middle ear function. They were tested with cVEMP and oVEMP in a random order. In implanted ear, cVEMP response got in 4 subject, but oVEMP response got in 2 subjects. However in non-implanted ear, cVEMP and oVEMP responses got in 5 subjects. VEMP wave forms revealed some difference in both latency and amplitude form CI user with normal inner ear structure and normal subject's reports from literature. Conclusion: Cochlear implant could change vestibular functions and this could be evaluated with VEMP especially to see saccul and utricul functions. It was known that dizziness and balance problems commonly accompany with inner ear malformations also after CI their complaint may increase. Different cochleovestibular malformations result in different VEMP recordings. But it is not clear that absence of VEMP result from cochleaovestibular malformation or from CI. Therefore, further studies need. [ABSTRACT FROM AUTHOR]