Cochlear implants and listening effort: the interaction of cognitive and sensory constraints

New York University School Of Medicine, New York NY

Investigators

Linked publications, trials & patents

Abstract

Despite the clinical success of cochlear implants (CIs), speech perception outcomes are quite variable. Current outcome studies and clinical practice focus almost exclusively on the CI user’s ability to repeat words and simple sentences. The goal of the proposed work is to transform our understanding of speech communication by CI users, and to bridge the gap between speech recognition and actual comprehension of everyday discourse, which is the typical goal of human communication. We aim to examine the cognitive mechanisms that enable CI users to adapt to a significantly degraded auditory signal, how they leverage linguistic knowledge to aid comprehension, and the extent to which listening effort impacts their performance. This proposal is divided into three main objectives. Aim 1 will investigate the role of linguistic context in perception of degraded auditory input, particularly the ways in which syntactic and semantic structure aid in speech recognition and comprehension in CI users. Although the use of context to aid word recognition is generally beneficial, a habitual over-reliance on context can be maladaptive. We introduce a metric designed to index a tendency to over-use context to the detriment of attention to phonological information. Aim 2 will stress- test human speech comprehension. We hypothesize that listeners requiring more listening effort are more susceptible to diverse communicative challenges. We aim to ascertain whether the additional effort could further cascade and result in a decline in comprehension for speech stimuli longer than single words or simple sentences. Aim 3 will test the impact of available processing time on narrative and sentence comprehension. Experiments will test the extent to which added processing time could enhance speech recognition and comprehension of normally rapid discourse and individual sentences. Our ultimate goal, in addition to studying intelligibility of isolated words or sentences, is to draw closer to real- world comprehension of everyday discourse. Comprehension will be evaluated not only quantitatively but also qualitatively, by using the semantic hierarchy effect, an index of relative recall of main ideas versus details. For all aims we will employ pupillometry as an objective physiological measure of listening effort, a feature of critical importance not captured by traditional speech perception measures. The proposed studies, complemented by a battery of cognitive, psychophysical, and clinical speech perception tests, aim to elucidate the mechanisms underlying successful communication in CI users. We aim to reveal factors that contribute to resilience or vulnerability to communicative challenges and produce data with the potential to guide the evaluation or rehabilitation of CI users. The outcome of this research may provide more meaningful measurements of communicative success, expanding beyond mere perceptual accuracy to encompass the effort required to achieve it. This approach to understanding speech comprehension in CI users is expected to significantly enhance the current standard of clinical research and practice.