Davis Timothy J, Gifford René H
Department of Hearing and Speech Sciences, Vanderbilt University, Nashville, TN.
J Speech Lang Hear Res. 2018 Mar 15;61(3):752-761. doi: 10.1044/2017_JSLHR-H-16-0441.
The primary purpose of this study was to derive spatial release from masking (SRM) performance-azimuth functions for bilateral cochlear implant (CI) users to provide a thorough description of SRM as a function of target/distracter spatial configuration. The secondary purpose of this study was to investigate the effect of the microphone location for SRM in a within-subject study design.
Speech recognition was measured in 12 adults with bilateral CIs for 11 spatial separations ranging from -90° to +90° in 20° steps using an adaptive block design. Five of the 12 participants were tested with both the behind-the-ear microphones and a T-mic configuration to further investigate the effect of mic location on SRM.
SRM can be significantly affected by the hemifield origin of the distracter stimulus-particularly for listeners with interaural asymmetry in speech understanding. The greatest SRM was observed with a distracter positioned 50° away from the target. There was no effect of mic location on SRM for the current experimental design.
Our results demonstrate that the traditional assessment of SRM with a distracter positioned at 90° azimuth may underestimate maximum performance for individuals with bilateral CIs.
本研究的主要目的是为双侧人工耳蜗（CI）使用者推导掩蔽空间释放（SRM）性能-方位函数，以全面描述SRM作为目标/干扰物空间配置的函数。本研究的次要目的是在受试者内研究设计中研究麦克风位置对SRM的影响。
采用自适应块设计，对12名双侧CI成人进行语音识别测量，测量11种空间分离条件下的语音识别，空间分离范围为-90°至+90°，步长为20°。12名参与者中有5名接受了耳后麦克风和T型麦克风配置的测试，以进一步研究麦克风位置对SRM的影响。
SRM会受到干扰刺激的半视野来源的显著影响，特别是对于在言语理解方面存在双耳不对称的听众。当干扰物与目标相距50°时，观察到最大的SRM。在当前实验设计中，麦克风位置对SRM没有影响。
我们的结果表明，传统的将干扰物置于90°方位角来评估SRM的方法可能会低估双侧CI使用者的最大性能。
