Characteristics Of Age-related Electric Response In Waardenburg Syndrome Patients With Cochlear Implantation

Objective Waardenburg Syndrome(WS)is a relatively rare autosomal dominant hereditary disease,which is partially recessive.Waardenburg syndrome is a disease characterized with dystopia canthorum,heterochromatic iris,white forelock and hereditary sensorineural deafness.Currently,the main treatment for WS patients with severe and profound sensorineural deafness is Cochlear implant(CI).The purpose of this study is to investigate the correlation between electrical evoked compound action potential(eCAP)and age,and the trend of postoperative electrical stimulation over time.The above results were used to evaluate the relationship between the number of Spiral ganglion neurons(SGN)with age in WS patients.Methods Patients who were diagnosed as Waardenburg Syndrome and received cochlear implantation from 2001 to 2017 were concluded.In the intraoperative eCAP test,patients were divided into<4 years old group and ?4 years old group.Patients after operation were all less than 4 years old.Non-syndromic hearing loss(NS)patients were selected as the control group according to the electrode type and the age at CI surgery.The intraoperative eCAP amplitude growth function(AGF)was used to perform linear regression analysis to calculate Slope value and predictive threshold(Threshold,T).Compare Slope value and the predictive threshold between WS and NS patients,and investigate the correlation with age and electrode position.The Threshold Level(T Level),Comfortable Level(C Level)and Dynamic Range(DR)were used to evaluate the electric stimulation after CI.Intraoperative eCAP data between two groups were statistically analyzed using an independent sample t test.The correlation between eCAP and age was analyzed by Linear Correlation Analysis.The eCAP evoked rate is calculated by chi-square test.One-way ANOVA was used to analyzed the effect of time after operation on electrical stimulation.Results Intraoperative eCAP results:10 WS patients were concluded in the<4 years old group,and 7 patients were concluded in the ?4 years old group.Slope value of WS patients was significantly lower than NS patients(P<0.01),and the threshold was significantly higher than control group(P<0.05),especially in patients over 4 years old.In WS patients,the Slope value over 4 years old was lower than that under 4 years old(P<0.05),and the threshold was higher than that under 4 years old(P<0.01).The Slope value is significantly negatively correlated with implantation age(r=-0.305,P<0.01).The Slope value of the proximal electrode of WS patients was significantly lower than that of the distal electrode.Both in the proximal and distal electrodes,the Slope value of WS patients is lower than that of NS patients.Mapping parameters after operation:7 WS patients were concluded.The T value of WS patients was significantly higher than that of NS patients(P<0.05),and the DR value was significantly lower than that of NS patients.In both groups,there was no significant difference in T and C values among 1-4 years after operation.The DR values in the third and fourth years were higher than those in the first and second years(P<0.01).Conclusion The Slope value in WS patients was significantly lower than that in NS patients,and gradually decreased with age.The predictive threshold in WS patients were significantly higher than those in NS patients over 4 years old.Because the Slope value was positively correlated with the number of spiral ganglion cells,it is speculated that the ganglion cells of WS patients are less than NS patients,and gradually decrease with aging.The minimum electrical stimulation that can be heard by WS patients was significantly higher than that of NS patients in the third and fourth years.The DR value was significantly lower than that of NS patients 4 years after surgery,and the DR values of both groups gradually increased,indicating WS.The patient's acceptance of electrical stimulation is narrower and the extent of sound that can be heard is not as good as that of NS patients.The above results show that in order to make WS patients have a better cochlear implant effect,early cochlear implant surgery is more urgent than other NS patients.