Aphasia is a common consequence of stroke, affecting approximately 1 million individuals in the United States and often persisting as a chronic condition. A growing body of work suggests that persons with chronic aphasia (PWA) are poorer than age- and hearing-matched controls at understanding speech when background sounds, or auditory maskers, are present. However, little is currently known about how auditory masking affects listening effort in PWA. Listening effort?that is, the cognitive resources directed towards decoding an auditory signal?is a key construct in the study of receptive speech processing. The presence of auditory maskers can often result in substantial increases in listening effort, which in turn can have significant negative ramifications for listeners, such as increased stress and fatigue, as well as the availability of fewer remaining resources to direct towards concurrent cognitive-linguistic operations. Because auditory masking is ubiquitous in real-world social and community environments (e.g. restaurants, stores, family/social gatherings), gaining a better understanding of this topic is crucial in understanding everyday communication in PWA. This proposal therefore consists of a close investigation into listening effort in aphasia under auditory masking conditions. This investigation is part of a comprehensive training plan that will allow the candidate to gain proficiency in specific tools?including pupillometry, electroencephalography (EEG), and structural magnetic resonance imaging (MRI)?and apply them to address several research aims, under the advisement of a mentoring team of experienced scientists. During the mentored phase, the project will aim to examine whether listening effort is higher in PWA than in age- and hearing-matched controls, as well as to identify possible relationships between brain lesion location and listening effort in PWA. During this initial phase, the candidate will receive training in pupillometry and EEG as measures of listening effort, as well as in structural MRI to collect data on lesion location, in order to compare listening effort in PWA vs controls. During the independent phase, the project will aim to assess the effects of several specific types of auditory masker manipulations, including masker type and location, on listening effort in PWA and controls. Finally, the effect of increased listening effort on verbal working memory in PWA will be directly examined. Throughout the project, careful consideration will be given to differentiating between the effects of aphasia, age, and hearing loss on listening effort. Results will provide critical information about how auditory masking affects PWA, and may have implications for social engagement, community participation, and quality of life in this population. Completion of the project will also allow the candidate to launch an independent research career investigating clinically relevant questions in aphasia and related neurogenic cognitive-communication disorders.
Individuals with chronic stroke-induced aphasia frequently report difficulty listening to and understanding speech in environments where background sounds are present. This study investigates listening effort, as measured by pupillometry, electroencephalography, and self-report, in individuals with aphasia and in controls, under a variety of listening conditions.
