The Changes Of Sound Localization Ability In Adults With Bilateral Sensorineural Hearing Loss After Unilateral Cochlear Implantation

Objective With extensive development of cochlear implant surgery,hearing function after implantation is drawing more and more attention.Sound localization is related to speech perception and has become one of the regular hearing examinations.Our experiment tested the horizontal sound localization(SL)ability of 17 bilateral sensorineural hearing loss adults with unilateral cochlear implantation(CI).We hope to find out the best fitting mode and the factors that may influence the SL ability,and to discuss the plasticity of in central nervous system(CNS).Methods 17 adult bilateral sensorineural hearing loss patients with unilateral CI were selected.The test was taken place in qualified audiometric room.All subjects took the root mean square(RMS)error and minimum audible angle(MAA)tests with the self-developed device(Patent number:No.200520017252.1)in different fitting patterns at different time as well as the speech recognition score(SRS)test.Results Subjects with bilateral hearing aids before CI,their RMS error was(28.43±11.14°).Subjects with CI using experience for 1 month,the RMS error when using uni-CI and bimodal was(42.00±3.67°)and(35.72±7.19°)respectively.Subjects with CI using experience for 6 months,the RMS error when using uni-CI and bimodal was(41.06±3.17°)and(36.36±5.53°)respectively.1 month and 6 months after CI activation,the MAA of bimodal was(152.00±39.32°)and(152.00±39.32°)respectively.We found that SL ability was better by means of bimodal than uni-CI at both 1 and 6 months,p<0.05,with statistical difference.Additionally,there is a decline in SL ability comparing with using bilateral hearing aids before the surgery.Meanwhile,the SL ability was related to hearing level of non-implanted ear.Moreover 6 months after activation the cochlear,the SRS of uni-CI and bimodal was(37.50±28.84)and(69.83±29.82)respectively,P<0.05,with statistical difference.Conclusion Adult patients with bilateral sensorineural hearing loss,within 6 months after activation the CI,the SL ability is better when using bimodal than uni-CI.However,comparing with bilateral hearing aids fitting before the surgery,the SL is worse when using both fitting patterns after the surgery.Subjects with uni-CI,better hearing level of contralateral ear could acquire better SL ability.There is no Statistic difference of SL ability between 1 month and 6 months uni-CI application.