Auditory Neuroscience Laboratory, Roxelyn and Richard Pepper Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL.
Department of Audiology, All India Institute of Speech and Hearing, Mysuru.
Am J Audiol. 2022 Sep;31(3):707-718. doi: 10.1044/2022_AJA-22-00029. Epub 2022 Aug 4.
Speech recognition in noise is a ubiquitous problem in older listeners. Speech, the most commonly encountered noise in the real world, causes greater masking than noise maskers, a phenomenon called informational masking (IM). This is due to the lexical-semantic and/or acoustic-phonetic information present in speech maskers. In this study, we aimed to observe the age-related differences in speech recognition and the magnitudes of IM when the maskers varied in the type of linguistic information.
In 30 young and 30 older individuals, we measured the signal-to-noise ratio required to obtain 50% correct identification under four-talker babble (lexical-semantic and acoustic-phonetic information), four-talker reverse babble (predominantly acoustic-phonetic information), and speech-shaped noise (SSN; energetic).
In both groups, the four-talker babble caused the greatest masking effect (worst performances), whereas the SSN resulted in the least masking effect (best performances). The effectiveness of IM due to the lexical-semantic information was comparable between the two groups. However, the effectiveness of IM due to the acoustic-phonetic information was significantly higher in the older listeners, causing worse performances.
The greater effectiveness of IM due to the acoustic-phonetic information (worse performance) could be due to the minimal-to-mild high-frequency hearing loss and the consequent temporal processing deficits observed in the older listeners. However, it is possible that the older listeners can employ compensatory mechanisms (such as life experiences, contextual cues, employing higher listening efforts, among many possible other mechanisms) to overcome some of these deficits.
在老年听众中，噪声环境下的语音识别是一个普遍存在的问题。语音是现实世界中最常见的噪声，它比噪声掩蔽器造成更大的掩蔽效应，这种现象称为信息掩蔽（IM）。这是由于语音掩蔽器中存在词汇语义和/或声学语音信息。在这项研究中，我们旨在观察当掩蔽器的语言信息类型不同时，言语识别和 IM 幅度随年龄的变化差异。
在 30 名年轻和 30 名老年个体中，我们测量了在四声道闲聊（词汇语义和声学语音信息）、四声道反向闲聊（主要是声学语音信息）和语音噪声（SSN；能量）下，获得 50%正确识别所需的信噪比。
在两组中，四声道闲聊造成最大的掩蔽效应（最差表现），而 SSN 导致最小的掩蔽效应（最佳表现）。两组之间，由于词汇语义信息导致的 IM 有效性相当。然而，由于声学语音信息导致的 IM 有效性在老年听众中显著更高，导致更差的表现。
由于声学语音信息导致的 IM 有效性更高（表现更差）可能是由于老年听众存在轻度至中度高频听力损失，以及随之而来的时间处理缺陷。然而，老年听众可能会采用补偿机制（例如生活经验、上下文线索、更高的听力努力等，以及许多其他可能的机制）来克服其中一些缺陷。
