听障儿童双耳双模式配戴的声源定位能力初探

The Sound Localization Abilities of Implanted Children Fitted with Hearing Aids in the Opposite Ears

目的探讨双耳双模式配戴能否帮助听障儿童改善声源定位能力以及哪些因素可能影响双耳双模式声源定位优势的发挥。方法采用强迫二选一任务，比较16名听障儿童在不同助听模式及不同声源角度下的声源定位能力。结果声源位于90°／270°时，38％的被试体现出双耳双模式的声源定位优势1位于45°／315°时，优势比例下降到25％。进一步分析表明，人工耳蜗麦克风的位置以及术前双耳配戴助听器的经验与双耳双模式声源定位优势的发挥密切相关。结论声源定位能力是听障儿童日常生活中的难点，即使双耳双模式配戴，也仅在声源位于左右方时，比单侧耳蜗状态体现出一定优势，随着声源角度的减小，双耳强度差和时间差线索减弱，双耳双模式的声源定位优势也随之减小。人工耳蜗的麦克风须放置在正确位置，否则会影响声源定位能力。此外，术前助听器配戴经验可能会影响听障儿童利用双耳线索的能力。

Objective To investigate that if the binaural-bimodal fitting can improve the sound localization abilities of hearing-impaired children and what factors influence the binaural-bimodal advantage in sound localization ability. Methods The sound localization abilities of 16 subjects were tested under different hearing aid modes and sound source angles with two-alternative forced-choice tasks. Results When the sound source was located in 90°/270°, 38% of the subjects showed the binaural-birnodal advantage, and the proportion fell to 25% in 45°/315°location. According to further analysis, the binaural-bimodal advantage in sound localization was closely related with the microphone positions of CI and the experience with hearing aids before CI surgery. Conclusion It＇s difficult for children with a CI to localize the sound source. The binaural-bimodal condition is better than unilateral CI condition when the sound is located on the left and right side （maximum IID and ITD clues）, and the advantage decreases with the decrease of the sound source angles. The position of CI microphone can influence the sound localization ability, and the experience with hearing aids before CI surgery may be another factor that affects the binaural-birnodal advantage in sound localization. [Key words]Hearing-impaired child; Binaural-bimodal fitting; Sound localization