Cochlear Implants, Speech Perception and Cognitive Load

人工耳蜗术(CI)使严重听力损失的人能够理解口语。然而，有限的信号传输在听觉困难的情况下会造成问题，例如几个人同时说话。这些所谓的“鸡尾酒会”情况对参与很重要，但对听觉处理提出了很高的要求。此外，良好的认知处理能力很重要，因为它们可能会抵消听觉困难情况下的知觉需求，这可能会导致过度使用认知资源--即高水平的听力努力。人工耳蜗术的成功与否通常取决于言语测听测试。然而，由于各种原因，它们只是部分反映了日常生活中的言语感知。一个重要的原因是，日常交流通常是在一定的认知负荷下进行的，特别是涉及注意力和记忆能力：在鸡尾酒会上，通常不清楚下一个发言的是谁。因此，为了提取感兴趣的信息，必须监视几个潜在的信息源。此外，为了跟上对话，能够记住谁之前说过特定的话是至关重要的。在听觉困难的情况下，这种认知负荷对CI用户在言语感知中的影响以前从未被系统地研究过。因此，对于在与日常生活相关的条件下估计与CI的沟通能力，缺少一个重要的理解。该项目旨在通过研究不同认知负荷下的言语知觉并描述潜在的机制来缩小这一严重差距。尤其是考虑了CI使用者的个体认知能力，这可能在言语理解中起到重要作用，但到目前为止受到的关注有限。此外，在鸡尾酒会的情况下，不同的方法被用来确定与言语理解相关的听力努力，而区分竞争对手的能力是通过凝视来描述的。该项目的核心假设是知觉需求和认知负荷的结合对言语理解有显著的负面影响，并可能导致高水平的听力努力，但个体的认知表现可以起到中介作用。通过将语音识别、听力努力和认知考虑在内，该项目有望在更全面地看待CI用户在与日常生活相关的交流情景中的言语感知机制方面开辟新的视野，从而促进未来生态有效诊断和人工耳蜗术康复的发展。

Cochlear implants (CI) allow for understanding spoken language in people with severe hearing loss. However, the limited signal transmission causes problems in acoustically difficult situations, such as several people talking simultaneously. These so-called "cocktail-party" situations are important for participation but pose high demands on auditory processing. Moreover, good cognitive processing abilities are of importance, since they may counteract the perceptual demands in acoustically difficult situations that may lead to excessive use of cognitive resources – referred to as high levels of listening effort. The success of cochlear implantation is typically determined by speech audiometric tests. However, for various reasons, they only partially mirror speech perception in everyday life. One important reason is that everyday communication typically takes place under a certain cognitive load, particularly involving attention and memory capacity: In a cocktail-party situation it is often not clear who speaks next. Thus, several potential sources of information have to be monitored in order to extract the information of interest. Furthermore, in order to follow a conversation, being able to remember who has previously made a specific utterance is of vital importance. Impact of such a cognitive load on CI users during speech perception in acoustically difficult situations has never been investigated systematically before. Hence, an important understanding for the estimation of communication abilities with CIs in conditions relevant to everyday life is missing. The proposed project aims at closing this serious gap by investigating speech perception under varying cognitive load and describing the underlying mechanisms. In particular, individual cognitive abilities of CI users are considered, which may play an important role in speech understanding, but have received limited attention so far. In addition, different methods are used to determine the listening effort associated with speech understanding in cocktail-party situations and the ability to differentiate competing speakers is described by gaze fixations. The core hypothesis of this project is that the combination of perceptual demands and cognitive load has a significant negative impact on speech understanding and may result in high levels of listening effort, but that individual cognitive performance can serve as a mediator. By taking speech recognition, listening effort, and cognition into account the project is expected to open new horizons in terms of a more holistic view of CI users’ speech perception mechanisms in communication situations relevant to everyday life, consequently promoting future developments in ecologically valid diagnosis and rehabilitation with cochlear implants.