Pupillometry Assessment of Speech Recognition and Listening Experience in Adult Cochlear Implant Patients

Listening Effort Measured With Pupillometry in Cochlear Implant Users Depends on Sound Level, But Not on the Signal to Noise Ratio When Using the Matrix Test

OBJECTIVES

We investigated whether listening effort is dependent on task difficulty for cochlear implant (CI) users when using the Matrix speech-in-noise test. To this end, we measured peak pupil dilation (PPD) at a wide range of signal to noise ratios (SNR) by systematically changing the noise level at a constant speech level, and vice versa.

DESIGN

A group of mostly elderly CI users performed the Dutch/Flemish Matrix test in quiet and in multitalker babble at different SNRs. SNRs were set relative to the speech-recognition threshold (SRT), namely at SRT, and 5 and 10 dB above SRT (0 dB, +5 dB, and +10 dB re SRT). The latter 2 conditions were obtained by either varying speech level (at a fixed noise level of 60 dBA) or by varying noise level (with a fixed speech level). We compared these PPDs with those of a group of typical hearing (TH) listeners. In addition, listening effort was assessed with subjective ratings on a Likert scale.

RESULTS

PPD for the CI group did not significantly depend on SNR, whereas SNR significantly affected PPDs for TH listeners. Subjective effort ratings depended significantly on SNR for both groups. For CI users, PPDs were significantly larger, and effort was rated higher when speech was varied, and noise was fixed for CI users. By contrast, for TH listeners effort ratings were significantly higher and performance scores lower when noise was varied, and speech was fixed.

CONCLUSIONS

The lack of a significant effect of varying SNR on PPD suggests that the Matrix test may not be a feasible speech test for measuring listening effort with pupillometric measures for CI users. A rating test appeared more promising in this population, corroborating earlier reports that subjective measures may reflect different dimensions of listening effort than pupil dilation. Establishing the SNR by varying speech or noise level can have subtle, but significant effects on measures of listening effort, and these effects can differ between TH listeners and CI users.

Changes on clinical and participatory outcomes in people with severe-to-profound hearing loss after cochlear implantation: protocol of a multicentre prospective observational cohort study - Societal Merit of Intervention on Hearing Loss Evaluation (SMILE)

INTRODUCTION

Cochlear implantation (CI) is a (cost-)effective intervention for people with severe or profound hearing loss. Since its introduction experience increased and the technology evolved, leading to better results and relaxation of CI eligibility criteria. Meanwhile, with national healthcare costs increasing there is a need for evidence of healthcare technology's value. This protocol describes a study to investigate clinical and participatory outcomes after CI for the currently (expanded) eligible hearing impaired population. The study adds to the current evidence base through its multicentre design, long-term follow-up and use of participatory outcomes alongside standard clinical outcomes.

METHODS

This multicentre prospective observational cohort study will include at least 156 adult patients with severe-to-profound hearing loss, approximately evenly divided into two groups (1, ages 18-65 years and 2, age >65 years). The measurements consist of audiometry, cognition tests, listening effort tests and multiple generic and disease specific questionnaires. Questionnaires will be administered twice before CI, soon after inclusion at CI referral and shortly before CI surgery, with an annual follow-up of 3 years after CI. The Impact on Participation and Autonomy questionnaire will be used to assess participation. Generalised models (linear, logistic, Poisson) will be used. Mixed effects models will be used to investigate changes over time while exploring differences in subgroups and the influence of covariates.

ETHICS AND DISSEMINATION

The study has received ethical approval from the Medical Ethical Committee of all participating centres. The results could provide valuable insights into changes in participatory outcomes of people with severe-to-profound hearing loss after CI. Results will be disseminated through peer-reviewed journals, scientific conferences and professional and patient organisation meetings.

TRIAL REGISTRATION NUMBER

NCT05525221.

Speech recognition in noise task among children and young-adults: a pupillometry study

Introduction

Children experience unique challenges when listening to speech in noisy environments. The present study used pupillometry, an established method for quantifying listening and cognitive effort, to detect temporal changes in pupil dilation during a speech-recognition-in-noise task among school-aged children and young adults.

Methods

Thirty school-aged children and 31 young adults listened to sentences amidst four-talker babble noise in two signal-to-noise ratios (SNR) conditions: high accuracy condition (+10 dB and  + 6 dB, for children and adults, respectively) and low accuracy condition (+5 dB and + 2 dB, for children and adults, respectively). They were asked to repeat the sentences while pupil size was measured continuously during the task.

Results

During the auditory processing phase, both groups displayed pupil dilation; however, adults exhibited greater dilation than children, particularly in the low accuracy condition. In the second phase (retention), only children demonstrated increased pupil dilation, whereas adults consistently exhibited a decrease in pupil size. Additionally, the children's group showed increased pupil dilation during the response phase.

Discussion

Although adults and school-aged children produce similar behavioural scores, group differences in dilation patterns point that their underlying auditory processing differs. A second peak of pupil dilation among the children suggests that their cognitive effort during speech recognition in noise lasts longer than in adults, continuing past the first auditory processing peak dilation. These findings support effortful listening among children and highlight the need to identify and alleviate listening difficulties in school-aged children, to provide proper intervention strategies.

Time Scales and Moments of Listening Effort Revealed in Pupillometry

This article offers a collection of observations that highlight the value of time course data in pupillometry and points out ways in which these observations create deeper understanding of listening effort. The main message is that listening effort should be considered on a moment-to-moment basis rather than as a singular amount. A review of various studies and the reanalysis of data reveal distinct signatures of effort before a stimulus, during a stimulus, in the moments after a stimulus, and changes over whole experimental testing sessions. Collectively these observations motivate questions that extend beyond the "amount" of effort, toward understanding how long the effort lasts, and how precisely someone can allocate effort at specific points in time or reduce effort at other times. Apparent disagreements between studies are reconsidered as informative lessons about stimulus selection and the nature of pupil dilation as a reflection of decision making rather than the difficulty of sensory encoding.

Exploring the Correlations Between Measures of Listening Effort in Adults and Children: A Systematic Review with Narrative Synthesis

Listening effort (LE) describes the cognitive resources needed to process an auditory message. Our understanding of this notion remains in its infancy, hindering our ability to appreciate how it impacts individuals with hearing impairment effectively. Despite the myriad of proposed measurement tools, a validated method remains elusive. This is complicated by the seeming lack of association between tools demonstrated via correlational analyses. This review aims to systematically review the literature relating to the correlational analyses between different measures of LE. Five databases were used- PubMed, Cochrane, EMBASE, PsychINFO, and CINAHL. The quality of the evidence was assessed using the GRADE criteria and risk of bias with ROBINS-I/GRADE tools. Each statistically significant analysis was classified using an approved system for medical correlations. The final analyses included 48 papers, equating to 274 correlational analyses, of which 99 reached statistical significance (36.1%). Within these results, the most prevalent classifications were poor or fair. Moreover, when moderate or very strong correlations were observed, they tended to be dependent on experimental conditions. The quality of evidence was graded as very low. These results show that measures of LE are poorly correlated and supports the multi-dimensional concept of LE. The lack of association may be explained by considering where each measure operates along the effort perception pathway. Moreover, the fragility of significant correlations to specific conditions further diminishes the hope of finding an all-encompassing tool. Therefore, it may be prudent to focus on capturing the consequences of LE rather than the notion itself.

Pupillometry as a Measure of Listening Effort in Patients with Bone-Anchored Hearing Systems

The goal of this study is to assess speech comprehension and listening effort by means of pupillometry, in patients with bone-anchored hearing system (BAHS). The study was performed prospectively in a group of 21 hearing-impaired adults, unilaterally implanted with BAHS Ponto. Listening effort was compared in patients wearing two sound processors (Oticon Medical AB, Askim, Sweden): Ponto 3 SuperPower (P3SP) and Ponto Pro (PP). Every patient was invited to two visits, separated by a 3-month break. The first session was to establish the noise level needed to obtain 95% correct sentence recall in the hearing in noise test (HINT), when speech is presented at 70 dB SPL. During the second session, pupillometry, with the use of the above-mentioned conditions, was performed. The mean HINT scores obtained during the second visit were 96.3% for PP and 97.7% for P3SP (p = 0.9863). In pupillometry, no significant differences were found for average PPD (peak pupil dilation; p = 0.3247), average peak pupil dilation timing (p = 0.527) and for pupil dilation growth curves with both processors. The findings of this study suggest that BAHS users allocate similar listening effort with PP and P3SP when processing speech-in-noise at a sound pressure level not saturating Ponto Pro and at a fixed performance level of 95%. This finding applies to the patients who meet the qualification criteria for bone conduction devices and have BC in situ threshold average below 45 dB HL.

Perceived Listening Difficulties of Adult Cochlear-Implant Users Under Measures Introduced to Combat the Spread of COVID-19

Following the outbreak of the COVID-19 pandemic, public-health measures introduced to stem the spread of the disease caused profound changes to patterns of daily-life communication. This paper presents the results of an online survey conducted to document adult cochlear-implant (CI) users’ perceived listening difficulties under four communication scenarios commonly experienced during the pandemic, specifically when talking: with someone wearing a facemask, under social/physical distancing guidelines, via telephone, and via video call. Results from ninety-four respondents indicated that people considered their in-person listening experiences in some common everyday scenarios to have been significantly worsened by the introduction of mask-wearing and physical distancing. Participants reported experiencing an array of listening difficulties, including reduced speech intelligibility and increased listening effort, which resulted in many people actively avoiding certain communication scenarios at least some of the time. Participants also found listening effortful during remote communication, which became rapidly more prevalent following the outbreak of the pandemic. Potential solutions identified by participants to ease the burden of everyday listening with a CI may have applicability beyond the context of the COVID-19 pandemic. Specifically, the results emphasized the importance of visual cues, including lipreading and live speech-to-text transcriptions, to improve in-person and remote communication for people with a CI.

Adult Users of the Oticon Medical Neuro Cochlear Implant System Benefit from Beamforming in the High Frequencies

The Oticon Medical Neuro cochlear implant system includes the modes Opti Omni and Speech Omni, the latter providing beamforming (i.e., directional selectivity) in the high frequencies. Two studies compared sentence identification scores of adult cochlear implant users with Opti Omni and Speech Omni. In Study 1, a double-blind longitudinal crossover study, 12 new users trialed Opti Omni or Speech Omni (random allocation) for three months, and their sentence identification in quiet and noise (+10 dB signal-to-noise ratio) with the trialed mode were measured. The same procedure was repeated for the second mode. In Study 2, a single-blind study, 11 experienced users performed a speech identification task in quiet and at relative signal-to-noise ratios ranging from -3 to +18 dB with Opti Omni and Speech Omni. The Study 1 scores in quiet and in noise were significantly better with Speech Omni than with Opti Omni. Study 2 scores were significantly better with Speech Omni than with Opti Omni at +6 and +9 dB signal-to-noise ratios. Beamforming in the high frequencies, as implemented in Speech Omni, leads to improved speech identification in medium levels of background noise, where cochlear implant users spend most of their day.