Eriksholm Workshop on Hearing Impairment and Cognitive Energy

The Relationship Between Spatial Release From Masking and Listening Effort Among Cochlear Implant Users With Single-Sided Deafness

OBJECTIVES

To examine speech intelligibility and listening effort in a group of patients with single-sided deafness (SSD) who received a cochlear implant (CI). There is limited knowledge on how effectively SSD-CI users can integrate electric and acoustic inputs to obtain spatial hearing benefits that are important for navigating everyday noisy environments. The present study examined speech intelligibility in quiet and noise simultaneously with measuring listening effort using pupillometry in individuals with SSD before, and 1 year after, CI activation. The study was designed to examine whether spatial separation between target and interfering speech leads to improved speech understanding (spatial release from masking [SRM]), and is associated with a decreased effort (spatial release from listening effort [SRE]) measured with pupil dilation (PPD).

DESIGN

Eight listeners with adult-onset SSD participated in two visits: (1) pre-CI and (2) post-CI (1 year after activation). Target speech consisted of Electrical and Electronics Engineers sentences and masker speech consisted of AzBio sentences. Outcomes were measured in three target-masker configurations with the target fixed at 0° azimuth: (1) quiet, (2) co-located target/maskers, and (3) spatially separated (±90° azimuth) target/maskers. Listening effort was quantified as change in peak proportional PPD on the task relative to baseline dilation. Participants were tested in three listening modes: acoustic-only, CI-only, and SSD-CI (both ears). At visit 1, the acoustic-only mode was tested in all three target-masker configurations. At visit 2, the acoustic-only and CI-only modes were tested in quiet, and the SSD-CI listening mode was tested in all three target-masker configurations.

RESULTS

Speech intelligibility scores in quiet were at the ceiling for the acoustic-only mode at both visits, and in the SSD-CI listening mode at visit 2. In quiet, at visit 2, speech intelligibility scores were significantly worse in the CI-only listening modes than in all other listening modes. Comparing SSD-CI listening at visit 2 with pre-CI acoustic-only listening at visit 1, speech intelligibility scores for co-located and spatially separated configurations showed a trend toward improvement (higher scores) that was not significant. However, speech intelligibility was significantly higher in the separated compared with the co-located configuration in acoustic-only and SSD-CI listening modes, indicating SRM. PPD evoked by speech presented in quiet was significantly higher with CI-only listening at visit 2 compared with acoustic-only listening at visit 1. However, there were no significant differences between co-located and spatially separated configurations on PPD, likely due to the variability among this small group of participants. There was a negative correlation between SRM and SRE, indicating that improved speech intelligibility with spatial separation of target and masker is associated with a greater decrease in listening effort on those conditions.

CONCLUSIONS

The small group of patients with SSD-CI in the present study demonstrated improved speech intelligibility from spatial separation of target and masking speech, but PPD measures did not reveal the effects of spatial separation on listening effort. However, there was an association between the improvement in speech intelligibility (SRM) and the reduction in listening effort (SRE) from spatial separation of target and masking speech.

A Multisite Randomized Controlled Trial Comparing the Effectiveness of Two Self-Fit Methods to the Best-Practices Method of Hearing Aid Fitting

TRIAL DESIGN

This is a randomized multisite noninferiority comparative-effectiveness clinical trial with three parallel branches comparing a best-practices audiologist-fit method to two experimental self-fit (person-fit) methods. Outcomes were measured at 6 weeks and 6 months post-fit.

METHOD

Participants: Five hundred eighty-four participants met the following inclusion criteria and enrolled: (a) age between 50 and 79 years; (b) never used or tried hearing aids previously; (c) can speak, read, and understand English well; (d) willing to purchase the study hearing aids for $650/pair; (e) no diagnosis of a memory or cognitive impairment; (f) 25-item Hearing Handicap Inventory for the Elderly (HHIE) score > 4; (g) Montreal Cognitive Assessment score ≥ 23; and (h) not excluded due to specific audiometric criteria. The audiometric exclusion criteria, based on air-conduction pure-tone thresholds, were as follows: (a) thresholds at all frequencies (250-8000 Hz) < 20 dB HL, for both ears (no hearing loss); (b) pure-tone average for 500, 1000, 2000, and 4000 Hz (PTA4) in the better ear > 50 dB HL (greater than moderate hearing loss); and (c) interaural difference > 20 dB at three or more frequencies or ≥ 40 dB at 500 or 1000 Hz. Interventions: Three groups received the same hearing aids fitted either by an audiologist using best practices (Group AB) or by themselves using one of two efficacious self-fit methods (Groups CD and EF). Objectives: The effectiveness of each of the self-fit methods, CD and EF, was hypothesized to be noninferior to the professional-fit method, AB. Outcomes: The primary outcome measure was the global score from the Profile of Hearing Aid Benefit (PHAB), and the secondary outcome measure was the benefit score (unaided - aided) for the 25-item HHIE. Randomization: Participants were stratified into one of three hearing loss categories based on better-ear PTA4: normal (≤ 20 dB HL), mild (20.1-35 dB HL), or moderate (35.1-50 dB HL). The random assignment of sequential enrollees within each hearing loss category to the three treatment groups made use of a site-specific pregenerated randomization list produced from a random-numbers table. Blinding: It was not possible to blind the participants as to the fitting method used, but the research personnel assessing the outcomes were blinded to the treatment group.

RESULTS

Numbers randomized: The 584 enrollees were randomized to one of the three treatment groups: AB (n = 190), CD (n = 193), and EF (n = 201).

Trial status: The trial began on November 1, 2020, and 6-month outcomes were obtained from the last participant on March 29, 2024. Numbers analyzed: At the 6-week measurement interval, outcome measures were completed for 182 AB, 172 CD, and 178 EF participants, representing 91.1% of the 584 individuals who enrolled. At the 6-month interval, completed outcomes were available for 166 AB, 148 CD, and 151 participants, representing 79.6% of the 584 original enrollees. Outcome: Bootstrapped (N = 1,000) means and 95% confidence intervals (CIs) at 6 weeks were 16.4 (95% CI [14.3, 18.7]), 16.8 (95% CI [14.9, 18.6]), and 15.2 (95% CI [13.5, 17.1]) for the AB, CD, and EF treatment groups on the primary outcome measure (PHAB global). At 6 months, primary outcome scores were 15.5 (95% CI [13.4, 17.8]), 16.3 (95% CI [14.4, 18.2]), and 15.3 (95% CI [13.5, 17.3]) for the AB, CD, and EF treatment groups, respectively. At both measurement intervals, there were no significant effects of treatment group (p > .05) for the primary or secondary outcome measures. Harms: No significant adverse events or side effects were observed.

CONCLUSIONS

At both the 6-week and 6-month postfit intervals, each of the two self-fit methods (CD, EF) yielded outcomes (primary and secondary) that were noninferior to the professional-fit best-practices (AB) fitting method. In addition, on average, clinically meaningful benefit was provided regardless of the fitting method.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.28585145.

Age-Related Differences in Auditory Cortex Activity During Spoken Word Recognition

Understanding spoken words requires the rapid matching of a complex acoustic stimulus with stored lexical representations. The degree to which brain networks supporting spoken word recognition are affected by adult aging remains poorly understood. In the current study we used fMRI to measure the brain responses to spoken words in two conditions: an attentive listening condition, in which no response was required, and a repetition task. Listeners were 29 young adults (aged 19-30 years) and 32 older adults (aged 65-81 years) without self-reported hearing difficulty. We found largely similar patterns of activity during word perception for both young and older adults, centered on the bilateral superior temporal gyrus. As expected, the repetition condition resulted in significantly more activity in areas related to motor planning and execution (including the premotor cortex and supplemental motor area) compared to the attentive listening condition. Importantly, however, older adults showed significantly less activity in probabilistically defined auditory cortex than young adults when listening to individual words in both the attentive listening and repetition tasks. Age differences in auditory cortex activity were seen selectively for words (no age differences were present for 1-channel vocoded speech, used as a control condition), and could not be easily explained by accuracy on the task, movement in the scanner, or hearing sensitivity (available on a subset of participants). These findings indicate largely similar patterns of brain activity for young and older adults when listening to words in quiet, but suggest less recruitment of auditory cortex by the older adults.

Pupil Responses of Adults With Traumatic Brain Injury During Processing of Speech in Noise

Previous research has shown the effects of task demands on pupil responses in both normal hearing (NH) and hearing impaired (HI) adults. One consistent finding is that HI listeners have smaller pupil dilations at low levels of speech recognition performance (≤50%). This study aimed to examine the pupil dilation in adults with a normal pure-tone audiogram who experience serious difficulties when processing speech-in-noise. Hence, 20 adults, aged 26 to 62 years, with traumatic brain injury (TBI) or cerebrovascular accident (CVA) but with a normal audiogram participated. Their pupil size was recorded while they listened to sentences masked by fluctuating noise or interfering speech at 50% and 84% intelligibility. In each condition, participants rated their perceived performance, effort, and task persistence. In addition, participants performed the text reception threshold task—a visual sentence completion task—that measured language-related processing. Data were compared with those of age-matched NH and HI participants with no neurological problems obtained in earlier studies using the same setup and design. The TBI group had the same pure-tone audiogram and text reception threshold scores as the NH listeners, yet their speech reception thresholds were significantly worse. Although the pupil dilation responses on average did not differ between groups, self-rated effort scores were highest in the TBI group. Results of a correlation analyses showed that TBI participants with worse speech reception thresholds had a smaller pupil response. We speculate that increased distractibility or fatigue affected the ability of TBI participants to allocate effort during speech perception in noise.

Relations Between Self-Reported Daily-Life Fatigue, Hearing Status, and Pupil Dilation During a Speech Perception in Noise Task

Supplemental Digital Content is available in the text.

Objective:

People with hearing impairment are likely to experience higher levels of fatigue because of effortful listening in daily communication. This hearing-related fatigue might not only constrain their work performance but also result in withdrawal from major social roles. Therefore, it is important to understand the relationships between fatigue, listening effort, and hearing impairment by examining the evidence from both subjective and objective measurements. The aim of the present study was to investigate these relationships by assessing subjectively measured daily-life fatigue (self-report questionnaires) and objectively measured listening effort (pupillometry) in both normally hearing and hearing-impaired participants.

Design:

Twenty-seven normally hearing and 19 age-matched participants with hearing impairment were included in this study. Two self-report fatigue questionnaires Need For Recovery and Checklist Individual Strength were given to the participants before the test session to evaluate the subjectively measured daily fatigue. Participants were asked to perform a speech reception threshold test with single-talker masker targeting a 50% correct response criterion. The pupil diameter was recorded during the speech processing, and we used peak pupil dilation (PPD) as the main outcome measure of the pupillometry.

Results:

No correlation was found between subjectively measured fatigue and hearing acuity, nor was a group difference found between the normally hearing and the hearing-impaired participants on the fatigue scores. A significant negative correlation was found between self-reported fatigue and PPD. A similar correlation was also found between Speech Intelligibility Index required for 50% correct and PPD. Multiple regression analysis showed that factors representing “hearing acuity” and “self-reported fatigue” had equal and independent associations with the PPD during the speech in noise test. Less fatigue and better hearing acuity were associated with a larger pupil dilation.

Conclusions:

To the best of our knowledge, this is the first study to investigate the relationship between a subjective measure of daily-life fatigue and an objective measure of pupil dilation, as an indicator of listening effort. These findings help to provide an empirical link between pupil responses, as observed in the laboratory, and daily-life fatigue.

The Pupil Dilation Response During Speech Perception in Dark and Light: The Involvement of the Parasympathetic Nervous System in Listening Effort

Recently, the measurement of the pupil dilation response has been applied in many studies to assess listening effort. Meanwhile, the mechanisms underlying this response are still largely unknown. We present the results of a method that separates the influence of the parasympathetic and sympathetic branches of the autonomic nervous system on the pupil response during speech perception. This is achieved by changing the background illumination level. In darkness, the influence of the parasympathetic nervous system on the pupil response is minimal, whereas in light, there is an additional component from the parasympathetic nervous system. Nineteen hearing-impaired and 27 age-matched normal-hearing listeners performed speech reception threshold tests targeting a 50% correct performance level while pupil responses were recorded. The target speech was masked with a competing talker. The test was conducted twice, once in dark and once in a light condition. Need for Recovery and Checklist Individual Strength questionnaires were acquired as indices of daily-life fatigue. In dark, the peak pupil dilation (PPD) did not differ between the two groups, but in light, the normal-hearing group showed a larger PPD than the hearing-impaired group. Listeners with better hearing acuity showed larger differences in dilation between dark and light. These results indicate a larger effect of parasympathetic inhibition on the pupil dilation response of listeners with better hearing acuity, and a relatively high parasympathetic activity in those with worse hearing. Previously observed differences in PPD between normal and impaired listeners are probably not solely because of differences in listening effort.

Semantic context improves speech intelligibility and reduces listening effort for listeners with hearing impairment

OBJECTIVE

We investigated whether speech intelligibility and listening effort for hearing-aid users is affected by semantic context and hearing-aid setting.

DESIGN

Participants heard target sentences spoken in a reverberant background of cafeteria noise and competing speech. Participants reported each sentence verbally. Eight participants also rated listening effort after each sentence. Sentence topic was either the same as, or different from, the previous target sentence.

STUDY SAMPLE

Twenty participants with sensorineural hearing loss were fit binaurally with Signia receiver-in-the-canal hearing aids. Participants performed the task twice: once using the hearing aid's omnidirectional setting and once using the "Reverberant Room" setting, designed to aid listening in reverberant environments.

RESULTS

Participants achieved better speech intelligibility for same-topic than different-topic sentences, and when they used the "Reverberant Room" than the omnidirectional hearing-aid setting. Participants who rated effort showed a reliable reduction in listening effort for same-topic sentences and for the "Reverberant Room" hearing-aid setting. The improvement in speech intelligibility from semantic context (i.e. same-topic compared to different-topic sentences) was greater than the improvement gained from changing hearing-aid setting.

CONCLUSIONS

These findings highlight the enormous potential of cognitive (specifically, semantic) factors for improving speech intelligibility and reducing perceived listening effort in noise for hearing-aid users.

Effort Not Speed Characterizes Comprehension of Spoken Sentences by Older Adults with Mild Hearing Impairment

In spite of the rapidity of everyday speech, older adults tend to keep up relatively well in day-to-day listening. In laboratory settings older adults do not respond as quickly as younger adults in off-line tests of sentence comprehension, but the question is whether comprehension itself is actually slower. Two unique features of the human eye were used to address this question. First, we tracked eye-movements as 20 young adults and 20 healthy older adults listened to sentences that referred to one of four objects pictured on a computer screen. Although the older adults took longer to indicate the referenced object with a cursor-pointing response, their gaze moved to the correct object as rapidly as that of the younger adults. Second, we concurrently measured dilation of the pupil of the eye as a physiological index of effort. This measure revealed that although poorer hearing acuity did not slow processing, success came at the cost of greater processing effort.