Dubno Judy R, Ahlstrom Jayne B, Horwitz Amy R
Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425-5500, USA.
J Speech Lang Hear Res. 2008 Apr;51(2):539-56. doi: 10.1044/1092-4388(2008/039).
Three experiments measured benefit of spatial separation, benefit of binaural listening, and masking-level differences (MLDs) to assess age-related differences in binaural advantage.
Participants were younger and older adults with normal hearing through 4.0 kHz. Experiment 1 compared spatial benefit with and without head shadow. Sentences were at 0 degrees, and speech-shaped noise was at 0 degrees, 90 degrees, or +/-90 degrees. Experiment 2 measured binaural benefit with the near ear unplugged compared with plugged for sentences at 0 degrees and masker at 90 degrees. Experiment 3 measured MLDs under earphones for 0.5-kHz pure tones in Gaussian and low-noise noise, and spondees in speech-shaped noise.
Spatial-separation benefit for speech did not differ significantly for younger and older adults but was smaller than predicted by an audibility-based model for older adults and larger than predicted for younger adults. Binaural listening benefit was observed for younger participants only. Tonal MLDs suggested that listeners benefit from interaural difference cues during noise dips for signals out of phase. Neither tonal nor speech MLDs differed significantly between younger and older participants.
Binaural processing of sentences revealed some age-related deficits in the use of interaural difference cues, whereas no deficits were observed for more simple detection or recognition tasks.
进行三项实验，测量空间分离益处、双耳聆听益处和掩蔽级差（MLD），以评估双耳优势方面与年龄相关的差异。
参与者为听力在4.0千赫以下正常的年轻和年长成年人。实验1比较了有无头影时的空间益处。句子位于0度，言语噪声位于0度、90度或±90度。实验2测量了在近耳堵塞与未堵塞情况下，句子位于0度且掩蔽声位于90度时的双耳益处。实验3测量了耳机下0.5千赫纯音在高斯噪声和低噪声环境中的MLD，以及言语噪声中韵脚词的MLD。
年轻和年长成年人在言语空间分离益处方面无显著差异，但对于年长成年人，该益处小于基于可听度模型的预测值，而对于年轻成年人则大于预测值。仅在年轻参与者中观察到双耳聆听益处。音调MLD表明，对于异相信号，听众在噪声低谷期间受益于双耳差异线索。年轻和年长参与者在音调及言语MLD方面均无显著差异。
句子的双耳处理显示出在使用双耳差异线索方面存在一些与年龄相关的缺陷，而在更简单的检测或识别任务中未观察到缺陷。
