1Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA; 2Cochlear Americas, Departments of Clinical Services and Research, Centennial, Colorado, USA; and 3Cochlear AG, Department of Clinical Technical Services, Basel, Switzerland.
Ear Hear. 2017 Sep/Oct;38(5):539-553. doi: 10.1097/AUD.0000000000000418.
The primary objective of this study was to assess the effect of electric and acoustic overlap for speech understanding in typical listening conditions using semidiffuse noise.
This study used a within-subjects, repeated measures design including 11 experienced adult implant recipients (13 ears) with functional residual hearing in the implanted and nonimplanted ear. The aided acoustic bandwidth was fixed and the low-frequency cutoff for the cochlear implant (CI) was varied systematically. Assessments were completed in the R-SPACE sound-simulation system which includes a semidiffuse restaurant noise originating from eight loudspeakers placed circumferentially about the subject's head. AzBio sentences were presented at 67 dBA with signal to noise ratio varying between +10 and 0 dB determined individually to yield approximately 50 to 60% correct for the CI-alone condition with full CI bandwidth. Listening conditions for all subjects included CI alone, bimodal (CI + contralateral hearing aid), and bilateral-aided electric and acoustic stimulation (EAS; CI + bilateral hearing aid). Low-frequency cutoffs both below and above the original "clinical software recommendation" frequency were tested for all patients, in all conditions. Subjects estimated listening difficulty for all conditions using listener ratings based on a visual analog scale.
Three primary findings were that (1) there was statistically significant benefit of preserved acoustic hearing in the implanted ear for most overlap conditions, (2) the default clinical software recommendation rarely yielded the highest level of speech recognition (1 of 13 ears), and (3) greater EAS overlap than that provided by the clinical recommendation yielded significant improvements in speech understanding.
For standard-electrode CI recipients with preserved hearing, spectral overlap of acoustic and electric stimuli yielded significantly better speech understanding and less listening effort in a laboratory-based, restaurant-noise simulation. In conclusion, EAS patients may derive more benefit from greater acoustic and electric overlap than given in current software fitting recommendations, which are based solely on audiometric threshold. These data have larger scientific implications, as previous studies may not have assessed outcomes with optimized EAS parameters, thereby underestimating the benefit afforded by hearing preservation.
本研究的主要目的是在典型的听力环境下，使用半扩散噪声评估言语理解中电声重叠的效果。
本研究采用了一个被试内、重复测量设计，包括 11 名有功能残余听力的经验丰富的成年植入者（13 只耳朵），他们在植入耳和非植入耳都有听力。助听的声带宽是固定的，耳蜗植入物（CI）的低频截止频率被系统地改变。评估是在 R-SPACE 声音模拟系统中完成的，该系统包括一个来自八个扬声器的半扩散餐厅噪声，这些扬声器环绕在受试者头部周围。AzBio 句子在 67 dBA 下呈现，信噪比在+10 到 0 dB 之间变化，以确保 CI 单独使用时的正确百分比约为 50%到 60%，此时的带宽是全频的。所有受试者的听力条件包括 CI 单独、双模式（CI+对侧助听器）和双侧电声刺激（EAS；CI+双侧助听器）。所有患者都在所有条件下测试了低于和高于原始“临床软件推荐”频率的低频截止值。所有条件下，受试者都根据视觉模拟量表的听力者评分来估计听力难度。
主要有三个发现：（1）在大多数重叠条件下，植入耳的残余听力有统计学上的显著益处；（2）默认的临床软件推荐很少能产生最高水平的言语识别（13 只耳朵中的 1 只）；（3）EAS 重叠大于临床推荐值会显著提高言语理解能力。
对于有残余听力的标准电极 CI 接受者来说，在实验室的餐厅噪声模拟中，电声刺激的频谱重叠会显著提高言语理解能力，并减少听力负担。总之，EAS 患者可能会从比当前软件拟合建议更大的电声重叠中获益更多，而这些建议仅仅是基于听力阈值。这些数据具有更大的科学意义，因为之前的研究可能没有评估优化后的 EAS 参数所带来的结果，从而低估了听力保护带来的益处。
