A Study On The Influence Of Implantation Age And Side On The Development And Remodeling Of Auditory Cortex In Prelingual Deaf Children With Cochlear

Objective:Cochlear implant(CI)surgery is currently internationally recognized as the only effective method to solve severe-to-profounds sensorineural hearing loss.However,the effects of cochlear implantation have huge individual differences in hearing,speech and language functions after implantation.Although some cross-sectional studies have found that implantation age,preoperative residual hearing and other factors are the main factors that affect the effect of CI implantation in post-lingual deaf adults,the explanations that can be made by these factors are quite limited.The implant side is a problem that clinicians need to pay attention to,and there is insufficient evidence to support the medical decision on the implant side,especially neurological evidence.Functional near-infrared spectroscopy(fNIRS)can be safely and repeatedly used in infants and children to map the neural characteristics of cerebral cortical changes related to their hearing and language ability learning and development.Our research carried out a longitudinal follow-up survey of prelingual deaf children with severe-to-profound sensorineural hearing loss.The key factors that influence the effects of cochlear implantation and the development of neural mechanisms in the early hearing deprivation of young children with prelinguistic deafness were examined.This research is mainly divided into two parts:1.The effect of age at implantation on cochlear implant recipients in prelingually deaf childrenMethods:Twenty-two prelingual deaf children(16 males and 6 females)with unilateral cochlear implants with bilateral severe-to-profound sensorineural hearing loss participated in this study.Infant-Toddler Meaningful Auditory Integration Scale(IT-MAIS/MAIS),categories of Auditory Performance(CAP),speech intelligibility rate(SIR)to evaluate the patient’s post-implantation effect.And through fNIRS to evaluate the neural results,the stimulation conditions are speech and music conditions.After preprocessing the neuroimaging and behavioral data,SPSS statistical analysis software was used to perform repeated measures analysis of variance and covariance analysis.Result:No significant statistical difference was found at 1 month after turning on.The main effect between implantation age groups was significant in the 9th(F=4.977,p=0.037,partial η2=0.199)and 15th(F=4.665,p=0.043,partial η2=0.189)channels under the condition of speech at 6 months after the turn-on.Under music conditions,15 channels showed significant main effects between implantation age groups(F=4.719,p=0.042,partialη 2=0.191).The main effect of the stimulus conditions on the channel 2 was significant in the test 12 months after the turn-on.Implantation age have a significant main effect under the condition of the 4th channel music stimulation(F=9.440,p=006,partial η2=0.321).The stimulus condition in channel 5 has a significant main effect(F=7.913,p=0.011,partialη=0.283).Under channel 10 speech stimulation conditions,implantation age has a significant main effect(F=4.946,p=0.042,partial η2=0.248).Behavioral results:There is a significant correlation between the age at implantation and the development of SIR levels during the 1-6 months after the turn-on(R=0.451,p=0.035).The age at implantation was positively correlated with the neurological results of the speech and music discriminating ability in the 5th channel at 6 months after turn-on(R=0.556,p=0.007).On the 16th channel,the age at implantation was positively correlated with the degree of activation response to speech stimulation at 6 months after torn一on(R=0.507,p=0.016),and positively correlated with the neurodevelopment during the 1-6 months after turn-on(R=0.494,p=0.019).But it was negatively correlated with neurodevelopment during 6-12 months after turn-on(R=0.591,p=0.005).Conclusion:(1)Implantation before 24 months has a significant speech perception advantage compared with implantation afterwards.And the older you are at the time of implantation,the worse your speech perception and expression skills will be 12-24 months after turning on.(2)The effect of age at the time of implantation is greatest at 3-6 months,and then gradually weakens.(3)Near-infrared measurement of the temporal cortex response to auditory stimuli can be used as an evaluation tool to predict the effect of cochlear implant surgery,but the correlation between different stimuli in different periods is different.(4)Music may be a more sensitive stimulus in the early prediction,while verbal stimulation is better in the later stage.2.The impact of the choice of implant side on the cochlear implant recipients of prelingual deaf childrenMethod:Twenty-two prelingual deaf children(23 males and 11 females)with unilateral cochlear implants with bilateral severe-to-profound sensorineural hearing loss participated in this study.Infant-Toddler Meaningful Auditory Integration Scale(IT-MAIS/MAIS),categories of Auditory Performance(CAP),speech intelligibility rate(SIR)to evaluate the patient’s post-implantation effect.And through fNIRS to evaluate the neural results,the stimulation conditions are speech and music conditions.After preprocessing the neuroimaging and behavioral data,SPSS statistical analysis software was used to perform repeated measures analysis of variance and covariance analysis.Result:About 2 weeks after turn-on:Under music conditions,the hemisphere factor has a significant main effect(F=4.270,p=0.047,partial η2=0.121).Under the condition of noise stimulation,the activation of the posterior temporal region in the left cochlear implant group was significantly lower than that in the right cochlear implant group.The implanted side has a significant main effect under noise conditions(F=5.248,p=0.029,partial η2=0.141).When signal is compared with noise,the left cochlear implant group has a significant signal-noise stimulus discrimination advantage in the posterior temporal region compared with the right cochlear implant group(F=4.456,p=0.043,partial η2=0.122);When the signal stimulated the anterior temporal area of the right hemisphere at about 3 months after the turn-on,the implant side factors showed a significant main effect(F=5,113,p=0.032,partial η2=0.164).And there is a significant interaction between implantation side and age at implantation(F=5.431,p=0.028,partial η2=0.173).Signal-noise situation:There is a significant main effect on the implantation side of the right anterior temporal area(F=4.595,p=0.040,partial 112=0.126);Between the two tests:Under noisy conditions,the main effect of the implantation side on the activation of the anterior temporal area was significant(F=4.579,p=0.036,partial η2=0.069).There was no significant difference in CI behavior outcomes between the left and right cochlear implant groups.We found that the ITMAIS/MAIS score at about 2 weeks after turn-on was significantly negatively correlated with the activation of the right anterior temporal area under signal stimulation(R=-0.451,p=0.007),but the difference between the groups was not significant.Conclusion:In this study,we found that(1)there was no significant difference between the left and right cochlear implant groups in the traditional CI outcome behavioral assessment in the early stage after cochlear implantation in young children.(2)However,compared with the right cochlear implant group,patients with left cochlear implants have significant advantages in acoustic signal perception,noise suppression,and signal-to-noise identification in neuroimaging examinations.(3)These advantages in the process of auditory development may be mainly due to the gradual enhancement of the ability of the left cochlear implanters to activate the noise-suppressing auditory cortex and is significantly stronger than the right cochlear implant group.(4)And the left cochlear implant group showed sensitivity to the age at the time of implantation,indicating that the early left implantation can make better use of the possibility of the critical period of brain development.In summary,we cautiously recommend that young children with severe-to-profound sensorineural hearing loss who have bilateral hearing loss basically symmetrical and do not have severe cochlear structural malformations should preferentially undergo left cochlear implantation.