Interactions between audition and cognition in hearing loss and aging

Understanding spoken language requires transmission of the acoustic signal up the ascending auditory pathway. However, in many cases speech understanding also relies on cognitive processes that act on the acoustic signal. One area in which cognitive processing is particularly striking during speech comprehension is when the acoustic signal is made less challenging, which might happen due to background noise, talker characteristics, or hearing loss. This chapter focuses on the interaction between hearing and cognition in hearing loss in aging. The chapter begins with a review of common age-related changes in hearing and cognition, followed by summary evidence from behavioral, pupillometric, and neuroimaging paradigms that elucidate the interplay between hearing ability and cognition. Across a variety of experimental paradigms, there is compelling evidence that when listeners process acoustically challenging speech, additional cognitive processing is required compared to acoustically clear speech. This increase in cognitive processing is associated with specific brain networks, with the clearest evidence implicating the cingulo-opercular and executive attention networks and prefrontal cortex. Individual differences in hearing and cognitive ability thus determine the cognitive demand faced by a particular listener, and the cognitive and neural resources needed to aid in speech perception.