Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, Champaign, IL 61820, USA.
Hum Factors. 2010 Aug;52(4):479-91. doi: 10.1177/0018720810380404.
A pair of experiments investigated the hypothesis that bimodal (auditory-visual) speech presentation and expanded auditory bandwidth would improve speech intelligibility and increase working memory performance for older adults by reducing the cognitive effort needed for speech perception.
Although telephone communication is important for helping older adults maintain social engagement, age-related sensory and working memory limits may make telephone conversations difficult.
Older adults with either age-normal hearing or mild-to-moderate sensorineural hearing loss performed a running memory task. Participants heard word strings of unpredictable length and at the end of each string were required to repeat back the final three words.Words were presented monaurally in telephone bandwidth (300 Hz to 3300 Hz) or expanded bandwidth (50 Hz to 7500 Hz), in quiet (65 dBZ SPL), or in white noise (65 dBZ SPL with noise at 60 dBZ SPL), with or without a visual display of the talker.
In quiet listening conditions, bimodal presentation increased the number of words correctly reported per trial but only for listeners with hearing loss and with high lipreading proficiency. Stimulus bandwidth did not affect performance. In noise, bimodal presentation and expanded bandwidth improved performance for all participant groups but did so by improving speech intelligibility, not by improving working memory.
Expanded bandwidth and bimodal presentation can improve speech perceptibility in difficult listening conditions but may not always improve working memory performance.
Results can inform the design of telephone features to improve ease of communication for older adults.
两项实验验证了一个假设，即双模态（视听）语音呈现和扩展听觉带宽可以通过减少语音感知所需的认知努力，提高语音可懂度并改善老年人的工作记忆表现。
尽管电话交流对于帮助老年人保持社交参与非常重要，但与年龄相关的感觉和工作记忆限制可能会使电话交谈变得困难。
具有正常年龄听力或轻度至中度感音神经性听力损失的老年人执行了一项连续记忆任务。参与者听到长度不可预测的单词串，在每个单词串结束时，他们需要重复最后三个单词。单词以单耳方式在电话带宽（300Hz 至 3300Hz）或扩展带宽（50Hz 至 7500Hz）中呈现，在安静（65dBZ SPL）或白噪声（65dBZ SPL 与 60dBZ SPL 的噪声）中呈现，有无说话者的视觉显示。
在安静聆听条件下，双模态呈现增加了每个试验中正确报告的单词数量，但仅适用于听力损失和高唇读能力的听众。刺激带宽不影响性能。在噪声中，双模态呈现和扩展带宽改善了所有参与者组的表现，但这是通过提高语音可懂度来实现的，而不是通过改善工作记忆来实现的。
扩展带宽和双模态呈现可以在困难的聆听条件下提高语音可感知性，但不一定总是能改善工作记忆表现。
结果可以为设计改善老年人通信便利性的电话功能提供信息。
