| Auditory neuropathy(AN)is a special type of sensorineural deafness.Otoacoustic emissionand(OAE)and/or cochlear microacoustic(CM)potential are the typical electrophysiological characteristics of auditory neurology,and the absence or extreme abnormality of ABR waveforms are the audiological characteristics.It is thought to be a result of auditory nerve dyssynchrony,resulting from the destruction of sound information at different points in the neural pathway,including cochlear inner hair cells,the synapses between the inner hair cells and the auditory nerve,or the ascending auditory nerve.According to the data of the 70 th World Health Assembly,360 million people worldwide suffer from hearing loss(HL),accounting for 5% of the total population,and the risk of HL among adolescents is as high as 1 billion people.The incidence of AN accounts for 2.4% to 15% of sensorineural hearing loss(SNHL),and the prevalence of AN in neonates with high risk factors is as high as 23%.AN is one of the common diseases that lead to hearing and speech communication disorders in infants and adolescents.Although cochlear implantation(CI)can improve the awareness of speech sounds and the ability to recognize words and sentences in these people,the effects of speech rehabilitation vary greatly,especially in the noisy environment,and speech perception is difficult.From the initial clinical phenotype recognition to the typical characteristics of electrophysiology and a series of studies on psychoacoustics and genetic and metabolic mechanisms,the classification,diagnosis and intervention of AN have gradually entered a precise stage.The clinical phenotype of AN is mainly characterized by fluctuating HL,decreased speech perception ability,especially in noise environment,and decreased spatial positioning ability.The unique characteristics of psychoacoustics include a decline in time domain processing ability,difficulty in speech recognition under noise,and a disproportionate decrease in speech recognition rate and pure tone hearing threshold.Speech recognition is the highest and most complex function of the human auditory system,which is closely related to the higher functions of the brain such as thinking,experience,memory and learning.Therefore,speech recognition is also the highest standard for testing hearing function.In contrast,50% of patients with AN develop before the age of 4 years,and bilateral disease accounts for 92%.At present,the assessment of the speech ability of such prelingual HL children mainly evaluates the language development level of hearing impaired children by conducting a variety of parents’ questionnaires related to speech scales in the form of interviews.The Categories of Auditory Behavior(CAP)scale,the Speech Intelligibility Rate(SIR)scale,the Infant-Toddling Meaningful Auditory Integration Scale(IT-MAIS)/ Meaningful Auditory Integration Scale(MAIS)and the Small Children Auditory Development Questionnaire(Littlears)and Parental Evaluation of Aural/Oral Performance of Children(Peach)scales.The results of the scale are easily influenced by the subjective judgment of parents.Therefore,this study aims to analyze and summarize the influencing factors of hearing and speech ability of patients with AN and to preliminarily explore the characteristics of objective evaluation indicators of AN.Part I The influencing factors of hearing and speech abilities of cochlear implant user with AN ObjectiveTo analyze the correlation between the high risk factors and etiology of an phenotype,the degree of hearing loss,subjective and objective audiological characteristics,the age of CI,the type of CI and imaging characteristics and the effects of auditory and speech rehabilitation after CI.MethodsThe medical history of 76 patients with AN with CI was collected,and the general condition,clinical characteristics,imaging characteristics,subjective and objective audiology characteristics,and the effects of auditory and speech rehabilitation after CI were analyzed.Outpatient or telephone follow-up was conducted.Parental interview questionnaire was used to analyze the children with preverbal deafness,including IT-MAIS/MAIS,CAP and SIR questionnaires.The children with preverbal deafness were given speech test.Subsound-field speech audioscopy was performed for patients with postlingual deafness,but CAP and SIR questionnaires were performed for adult patients with short operation time of cochlear implant.Results1.The total effective rate of CI in improving speech disorders of AN was85.5%(65/76),that is,40.8%(31/76)of postoperative speech ability was restored to normal,44.7%(34/76)of effective,10.6%(8/76)of poor effect and3.9%(3/76)of ineffective.2.There was a correlation between CI patients with auditory nerve dysplasia and/or internal auditory canal stenosis and those without.3.33 cases(34 ears)of 61 children with prelingual HL were evaluated under the sound field after adjusting the machine.The average hearing threshold was 38.05±6.63 d B HL(range: 27.5d B HL ～ 50 d B HL),and all of them could obtain good practical hearing.The average hearing threshold after cochlear implantation was increased from 78.33±17.34 d B HL to 32.58±9.26 d B HL,and the difference between preoperative and postoperative mean hearing threshold was statistically significant(P < 0.001).4.CAP level of 57 children increased from 0.25±0.69 to 5.51±1.67;SIR level increased from grade 1 preoperatively to 3.60±1.21,and the difference between CAP and SIR preoperatively and postoperatively was statistically significant(P < 0.001).Speech audiometry in 5 cases showed effective effect in4 cases and poor effect in 1 case.In the 15 cases of post-speech deafness,4 cases recovered to normal speech,1 case was effective,1 case was poor,and 1 case was ineffective.However,the recognition rate of monosyllabic,disyllable and quiet sentences was improved by more than 30% compared with that before operation.Eight patients received CAP and SIR questionnaire after surgery,and their CAP and SIR grades increased from 0.75±1.04 and 1.25±0.46 preoperatively to 6.00±1.41 and 4.75±0.71,respectively.The differences between CAP and SIR grades before and after surgery were statistically significant(P < 0.001).Conclusion1.CI can effectively improve the speech ability of patients with AN and extremely severe speech disorders.2.The effect of speech rehabilitation after CI in patients with auditory nerve implant is related to whether the patients are accompanied by auditory nerve dysplasia and/or with internal auditory canal stenosis.3.The HL of the postoperative residual ear with cochlear implant was faster than that of the non-operative ear.Part II The study of objective indexes of AN patients with CI.ObjectiveTo explore the significance of genetic testing in the evaluation of CI effect for patients with AN,and to analyze and summarize the characteristics of electrode impedance and ECAPs threshold monitored during the operation,and T,C and DR values of postoperative adjustment for patients with an,and to explore the specificity and regularity of these objective indicators.Methods1.Panel or WES detection of polygenic deafness was carried out by NSG target region capture technology.The pathogenicity of the mutation sites was evaluated by bioinformatics analysis method,and the influence of related gene variations on the hearing and speech effects after cochlear implantation was analyzed.2.Analyze and summarize the electrode impedance value and ECAPs threshold monitored during CI for patients with AN,as well as the debugging impedance value,T threshold,C threshold and DR of the post-operative speech processing program.Results1.A total of 19(41.3%)patients(46 of 76 CI users with AN)were detected with pathogenic sites or genetic variations of suspected pathogenic sites related to AN phenotypes.There were 11(57.9%,11/19)cases of OTOF gene variation,2(1.1%,2/19)cases of AIFM1 gene variation,2(1.1%,2/19)cases of TIMM8 A gene variation,1(0.5%,1/19)cases of TWNK gene variation,and 1(0.5%,1/19)cases of ADGRV1/GPR98 pathogenic/suspected pathogenic gene variants associated with AN were detected with GPR98 gene variant,1 case(0.5%,1/19)with MYO15 A gene variant and 1 case(0.5%,1/19)with MYO1 A gene variant and 27 cases(58.7%,29/46)with MYO1 A gene variant.The IT-MAIS/MAIS score was 32.00±7.64 after cochlear implantation.The CAP and SIR levels were increased from 0.27±0.47 and grade 1 to 6.18±0.98 and 3.82±0.98,respectively.The difference between them before and after surgery was statistically significant(P < 0.001).3.For patients with AN with extremely severe speech disorders caused by gene variants of AIFM1,TIMM8 A,TWNK,ADGRV1/GPR98 and MYO15 A,the hearing and speech effects of CI were all well rehabilitating.4.The electrode impedance value of the CI is the highest when the device is started up.As time goes by,the impedance value gradually decreases to a stable level.5.There was no correlation between the Cochlear Nucleus and MEDEL CI in the AN group and the SNHL group.6.After Cochlear Nucleus CI,the electrode comfort threshold was lower and its dynamic range was narrower than that of the SNHL group.However,the electrode comfort threshold was higher than that of the SNHL group except the electrode 1 ～ 2.The comfort threshold and threshold of MEDEL,AB 90 K and Nolcon CI users with AN were higher than those in patients with SNHL,but their dynamic range was wider than that in patients with SNHL,while Nolcon electrodes were narrower than that in patients with SNHL.Conclusions1.Genetic testing is a necessary testing method to clarify the etiology of AN.2.OTOF gene variants can be used as a severe speech impediment of auditory nerve disease effect of hearing speech rehabilitation after CI good predictors.3.For other genetic mutations cause auditory nerve lesions,patients can be satisfactory to listen to the hearing rehabilitation effect of nerve degeneration of CI indication selection provides a strong clinical guideline.3.The difference of T threshold,C threshold and DR threshold between auditory nerve patients and SNHL group after CI may be related to the number of neurons and hair cells remaining in auditory nerve. |
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