Souza Pamela, Arehart Kathryn, Neher Tobias
Communication Sciences and Disorders, Knowles Hearing Center, Northwestern University, Evanston IL, USA.
Speech, Language and Hearing Sciences, University of Colorado Boulder, Boulder CO, USA.
Front Psychol. 2015 Dec 16;6:1894. doi: 10.3389/fpsyg.2015.01894. eCollection 2015.
Working memory-the ability to process and store information-has been identified as an important aspect of speech perception in difficult listening environments. Working memory can be envisioned as a limited-capacity system which is engaged when an input signal cannot be readily matched to a stored representation or template. This "mismatch" is expected to occur more frequently when the signal is degraded. Because working memory capacity varies among individuals, those with smaller capacity are expected to demonstrate poorer speech understanding when speech is degraded, such as in background noise. However, it is less clear whether (and how) working memory should influence practical decisions, such as hearing treatment. Here, we consider the relationship between working memory capacity and response to specific hearing aid processing strategies. Three types of signal processing are considered, each of which will alter the acoustic signal: fast-acting wide-dynamic range compression, which smooths the amplitude envelope of the input signal; digital noise reduction, which may inadvertently remove speech signal components as it suppresses noise; and frequency compression, which alters the relationship between spectral peaks. For fast-acting wide-dynamic range compression, a growing body of data suggests that individuals with smaller working memory capacity may be more susceptible to such signal alterations, and may receive greater amplification benefit with "low alteration" processing. While the evidence for a relationship between wide-dynamic range compression and working memory appears robust, the effects of working memory on perceptual response to other forms of hearing aid signal processing are less clear cut. We conclude our review with a discussion of the opportunities (and challenges) in translating information on individual working memory into clinical treatment, including clinically feasible measures of working memory.
工作记忆——处理和存储信息的能力——已被确认为在困难聆听环境中语音感知的一个重要方面。工作记忆可以被设想为一个容量有限的系统，当输入信号不能轻易与存储的表征或模板匹配时，该系统就会被激活。当信号 degraded 时，这种“不匹配”预计会更频繁地发生。由于工作记忆容量因人而异，预计容量较小的人在语音 degraded 时，如在背景噪声中，语音理解能力会较差。然而，工作记忆是否（以及如何）应该影响实际决策，如听力治疗，还不太清楚。在这里，我们考虑工作记忆容量与对特定助听器处理策略的反应之间的关系。我们考虑了三种类型的信号处理，每种处理都会改变声学信号：快速作用的宽动态范围压缩，它使输入信号的幅度包络平滑；数字降噪，它在抑制噪声时可能会无意中去除语音信号成分；以及频率压缩，它改变频谱峰值之间的关系。对于快速作用的宽动态范围压缩，越来越多的数据表明，工作记忆容量较小的个体可能更容易受到这种信号改变的影响，并且可能从“低改变”处理中获得更大的放大益处。虽然宽动态范围压缩与工作记忆之间关系的证据似乎很充分，但工作记忆对其他形式的助听器信号处理的感知反应的影响尚不太明确。我们在综述的结尾讨论了将个体工作记忆信息转化为临床治疗的机会（和挑战），包括临床上可行的工作记忆测量方法。
