Neher Tobias, Wagener Kirsten C, Latzel Matthias
Medizinische Physik and Cluster of Excellence "Hearing4all", Dept. of Medical Physics and Acoustics, Carl-von-Ossietzky University, D-26111 Oldenburg, Germany.
Hörzentrum Oldenburg GmbH, Marie-Curie-Str. 2, D-26129 Oldenburg, Germany.
Hear Res. 2017 Sep;353:36-48. doi: 10.1016/j.heares.2017.07.014. Epub 2017 Jul 29.
Hearing aid (HA) users can differ markedly in their benefit from directional processing (or beamforming) algorithms. The current study therefore investigated candidacy for different bilateral directional processing schemes. Groups of elderly listeners with symmetric (N = 20) or asymmetric (N = 19) hearing thresholds for frequencies below 2 kHz, a large spread in the binaural intelligibility level difference (BILD), and no difference in age, overall degree of hearing loss, or performance on a measure of selective attention took part. Aided speech reception was measured using virtual acoustics together with a simulation of a linked pair of completely occluding behind-the-ear HAs. Five processing schemes and three acoustic scenarios were used. The processing schemes differed in the tradeoff between signal-to-noise ratio (SNR) improvement and binaural cue preservation. The acoustic scenarios consisted of a frontal target talker presented against two speech maskers from ±60° azimuth or spatially diffuse cafeteria noise. For both groups, a significant interaction between BILD, processing scheme, and acoustic scenario was found. This interaction implied that, in situations with lateral speech maskers, HA users with BILDs larger than about 2 dB profited more from preserved low-frequency binaural cues than from greater SNR improvement, whereas for smaller BILDs the opposite was true. Audiometric asymmetry reduced the influence of binaural hearing. In spatially diffuse noise, the maximal SNR improvement was generally beneficial. NS detection performance at 500 Hz predicted the benefit from low-frequency binaural cues. Together, these findings provide a basis for adapting bilateral directional processing to individual and situational influences. Further research is needed to investigate their generalizability to more realistic HA conditions (e.g., with low-frequency vent-transmitted sound).
助听器（HA）使用者从定向处理（或波束形成）算法中获得的益处可能存在显著差异。因此，本研究调查了不同双侧定向处理方案的适用性。研究对象为年龄、总体听力损失程度或选择性注意力测试表现无差异，但2kHz以下频率的听力阈值对称（N = 20）或不对称（N = 19）、双耳可懂度水平差异（BILD）差异较大的老年听众群体。使用虚拟声学技术并结合一对模拟的完全封闭的耳背式HA来测量助听语音接收情况。采用了五种处理方案和三种声学场景。这些处理方案在信噪比（SNR）改善和双耳线索保留之间的权衡上有所不同。声学场景包括一个正面目标说话者，其面对来自±60°方位的两个语音掩蔽器或空间扩散的自助餐厅噪声。对于两组听众，均发现BILD、处理方案和声学场景之间存在显著的交互作用。这种交互作用表明，在存在侧向语音掩蔽器的情况下，BILD大于约2dB的HA使用者从保留的低频双耳线索中获得的益处比从更大的SNR改善中获得的益处更多，而对于较小的BILD则情况相反。听力不对称降低了双耳听力的影响。在空间扩散噪声中，最大SNR改善通常是有益的。500Hz时的噪声检测性能可预测从低频双耳线索中获得的益处。总之，这些发现为使双侧定向处理适应个体和情境影响提供了依据。需要进一步研究以调查它们对更现实的HA条件（例如，有低频通气传输声音的情况） 的可推广性。
