Preoperative imaging and electrophysiological evaluation of cochlear implantation in children with cochlear nerve dysplasia

Abstract

Objective:The aim of this study is to investigate the use of CT, magnetic resonance imaging （MRI）, functional magnetic resonance （fMRI） and electrical evoked auditory brainstem response in children with cochlear nerve deficiency （CND） before cochlear implantation （CI） （electrically evoked auditory brain stem response, EABR） evaluated auditory pathway, auditory cortex function, and cochlear nerve function. Method:Of 6 children with bilateral profound sensorineural hearing loss, bilateral internal auditory meatus stenosis was diagnosed by CT as in 4 cases and unilateral internal auditory meatus stenosis in 1 case. In 3 cases, oblique sagittal MRI reconstruction of the internal auditory meatus showed only facial nerve and vestibular nerve existence. 6 cases were diagnosed as CND by imaging, among which underwent fMRI and EABR in 3 cases, respectively. All the children received unilateral CI and were followed up for at least 1 year after hearing and speech rehabilitation. Result:fMRI was examed in 3 cases with CND. It showed that the right auditory cortex was activated in 1 case after sound given to the left ear but no activation was found in the left cortex when sound given to the right ear. 1 case showed activation in bilateral transverse temporal gyrus while sound was given to the left, right and both ears at 2000Hz. Another case had no activation in both auditory cortex. EABR detection elicited V wave in 2 of 3 cases. 6 children received audiological and speech evaluation 1 month, 6 and 12 months after CI. Among them, the hearing level was improved within 6 months after surgery in 4 cases, and the threshold of sound field was （48.15±6.60） dB HL, MAIS and CAP scores were improved. However, SIR score improvement is limited in 3 cases. The hearing level was improved in 1 case, but speech rehabilitation was poor mainly due to the older age. Conclusion:Preoperative comprehensive application of imaging and electrophysiological evaluation of children with CND can more accurately assess the integrity of the auditory pathway and understand the function of the cochlear nerve. It has important reference significance for whether or not to perform surgery. There was a significant difference in auditory speech rehabilitation after CND in children with CND.