Exploring neurocognitive factors and brain activation in adult cochlear implant recipients associated with speech perception outcomes—A scoping review

Abstract

BackgroundCochlear implants (CIs) are considered an effective treatment for severe-to-profound sensorineural hearing loss. However, speech perception outcomes are highly variable among adult CI recipients. Top-down neurocognitive factors have been hypothesized to contribute to this variation that is currently only partly explained by biological and audiological factors. Studies investigating this, use varying methods and observe varying outcomes, and their relevance has yet to be evaluated in a review. Gathering and structuring this evidence in this scoping review provides a clear overview of where this research line currently stands, with the aim of guiding future research.ObjectiveTo understand to which extent different neurocognitive factors influence speech perception in adult CI users with a postlingual onset of hearing loss, by systematically reviewing the literature.MethodsA systematic scoping review was performed according to the PRISMA guidelines. Studies investigating the influence of one or more neurocognitive factors on speech perception post-implantation were included. Word and sentence perception in quiet and noise were included as speech perception outcome metrics and six key neurocognitive domains, as defined by the DSM-5, were covered during the literature search (Protocol in open science registries: 10.17605/OSF.IO/Z3G7W of searches in June 2020, April 2022).ResultsFrom 5,668 retrieved articles, 54 articles were included and grouped into three categories using different measures to relate to speech perception outcomes: (1) Nineteen studies investigating brain activation, (2) Thirty-one investigating performance on cognitive tests, and (3) Eighteen investigating linguistic skills.ConclusionThe use of cognitive functions, recruiting the frontal cortex, the use of visual cues, recruiting the occipital cortex, and the temporal cortex still available for language processing, are beneficial for adult CI users. Cognitive assessments indicate that performance on non-verbal intelligence tasks positively correlated with speech perception outcomes. Performance on auditory or visual working memory, learning, memory and vocabulary tasks were unrelated to speech perception outcomes and performance on the Stroop task not to word perception in quiet. However, there are still many uncertainties regarding the explanation of inconsistent results between papers and more comprehensive studies are needed e.g., including different assessment times, or combining neuroimaging and behavioral measures.Systematic review registrationhttps://doi.org/10.17605/OSF.IO/Z3G7W.

Motor Processing in Children With Cochlear Implants as Assessed by Functional Near-Infrared Spectroscopy

“…Cortical reorganization following CI may not always prevent the auditory cortex from responding to auditory stimuli ( Land et al, 2016 ). Quite to the contrary, some individuals with CI may integrate multisensory information very effectively ( Rouger et al, 2007 ) and cross-modal plasticity may strengthen their communication skills, especially those children who are familiar with sign language (see Beckers et al, 2023 for a comprehensive review on adult CI users). This is an unsettled on-going debate with many ramifications ( Anderson et al, 2017b ; Stropahl et al, 2016 ).…”

Variability in clinicians’ prediction accuracy for outcomes of adult cochlear implant users

“…This is especially relevant when considering that the majority of current clinical predictors cannot be addressed with auditory training or device programming (Moberly et al 2016). Given that other studies have found correlations between non-standard clinical measures, such as neurocognitive factors, and speech perception outcomes, it may be valuable to consider these factors when predicting outcomes (Beckers et al 2023). Goudey et al (2021) suggest that additional variance could be explained by information about patients' home and work environment, education, comorbidities, medication, rehabilitation, social interactions, and cognition.…”

Impact of SNR, peripheral auditory sensitivity, and central cognitive profile on the psychometric relation between pupillary response and speech performance in CI users

“…Non-verbal intelligence measured by Progressive Matrices is negatively correlated with the average PPD, suggesting that CI participants with higher non-verbal intelligence showed lower PPD across all SNR conditions. The relation between non-verbal intelligence and speech outcomes in CI users have been examined in past studies, but it was unclear how non-verbal intelligence affect listening effort (Mattingly et al, 2018;Moberly et al, 2019;Amini et al, 2023;Beckers et al, 2023). Non-verbal intelligence is typically found to relate positively with word or sentence recognition, indicating that higher ability to induce abstract relation helps recognizing sentences that have degraded resolution due to CI signal processing (Carpenter et al, 1990).…”

“…Multiple studies have shown significant correlation between spectral-temporal acuity with speech performance, suggesting that bottom-up auditory processing ability is important to explain CI variabilities (Aronoff and Landsberger, 2013;Lawler et al, 2017;DiNino and Arenberg, 2018). In addition to biological and audiological factors, individual cognitive capacities, i.e., top-down abilities, have been shown to affct both the speech and listening effort outcomes in CI users (Pisoni, 2000;Amini et al, 10.3389/fnins.2023.1307777 Frontiers in Neuroscience 03 frontiersin.org 2023; Beckers et al, 2023). Working memory (WM) is a factor of most interest due to its association with speech performance in pediatric and adult CI users, HI and old NH listeners (Pisoni and Cleary, 2003;Akeroyd, 2008;Rudner et al, 2011;Besser et al, 2013;Füllgrabe and Rosen, 2016;Kestens et al, 2021;Dingemanse and Goedegebure, 2022).…”

“…Nonverbal reasoning tests have also been suggested as a method to predict speech recognition in CI users, because the ability to solve new tasks using limited information should, intuitively, relate to the ability to fuse degraded auditory inputs into a meaningful percept. Past studies have reported a significant correlation between CI users' sentence recognition and their non-verbal reasoning skills, although the underlying relation between nonverbal reasoning and processing efficiency remains unclear (Carpenter et al, 1990;Mattingly et al, 2018;Moberly et al, 2019;Beckers et al, 2023). Cognitive inhibition is the ability to suppress distracting information, and past studies have shown that this ability could be linked with CI word and sentence recognition (Moberly et al, 2018;Tamati et al, 2020;Völter et al, 2021;Tamati and Moberly, 2022).…”