Using Speech Recall in Hearing Aid Fitting and Outcome Evaluation Under Ecological Test Conditions

Differences Between French and English in the Use of Suprasegmental Cues for the Short-Term Recall of Word Lists

PURPOSE

Greater recognition of the impact of hearing loss on cognitive functions has led speech/hearing clinics to focus more on auditory memory outcomes. Typically evaluated by scoring participants' recall on a list of unrelated words after they have heard the list read out loud, this method implies pitch and timing variations across words. Here, we questioned whether these variations could impact performance differentially in one language or another.

METHOD

In a series of online studies evaluating auditory short-term memory in normally hearing adults, we examined how pitch patterns (Experiment 1), timing patterns (Experiment 2), and interactions between the two (Experiment 3) affected free recall of words, cued recall of forgotten words, and mental demand. Note that visual memory was never directly tested; written words were only used after auditory encoding in the cued recall part. Studies were administered in both French and English, always conducted with native listeners.

RESULT

Confirming prior work, grouping mechanisms facilitated free recall, but not cued recall (the latter being only affected by longer presentation time) or ratings of mental demand. Critically, grouping by pitch provided more benefit for French than for English listeners, while grouping by time was equally beneficial in both languages.

CONCLUSION

Pitch is more useful to French- than to English-speaking listeners for encoding spoken words in short-term memory, perhaps due to the syllable-based versus stress-based rhythms inherent to each language.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.27048328.

Pupillometry reveals effects of pitch manipulation within and across words on listening effort and short-term memory

For individuals with hearing loss, even successful speech communication comes at a cost. Cochlear implants transmit degraded information, specifically for voice pitch, which demands extra and sustained listening effort. The current study hypothesized that abnormal pitch patterns contribute to the additional listening effort, even in non-tonal language native speaking normally hearing listeners. We manipulated the fundamental frequency (F0) within and across words, while participants listen and repeat (simple intelligibility task), or listen, repeat, and later recall (concurrent encoding task) the words. In both experiments, the F0 manipulations resulted in small changes in intelligibility but no difference in free recall or subjective effort ratings. Pupillary metrics were yet sensitive to these manipulations: pupil dilations were larger when words were monotonized (flat contour) or inverted (the natural contour flipped upside-down), and larger when successive words were organized into a melodic pattern. The most likely interpretation is that the natural or expected F0 contour of a word contributes to its identity and facilitate its matching and retrieval from the phonological representation stored in long-term memory. Consequently, degrading words' F0 contour can result in extra listening effort. Our results call for solutions to improve pitch saliency and naturalness in future development of cochlear implants' signal processing strategies, even for non-tonal languages.

Can Music Enhance Working Memory and Speech in Noise Perception in Cochlear Implant Users? Design Protocol for a Randomized Controlled Behavioral and Electrophysiological Study

BACKGROUND

A cochlear implant (CI) enables deaf people to understand speech but due to technical restrictions, users face great limitations in noisy conditions. Music training has been shown to augment shared auditory and cognitive neural networks for processing speech and music and to improve auditory-motor coupling, which benefits speech perception in noisy listening conditions. These are promising prerequisites for studying multi-modal neurologic music training (NMT) for speech-in-noise (SIN) perception in adult cochlear implant (CI) users. Furthermore, a better understanding of the neurophysiological correlates when performing working memory (WM) and SIN tasks after multi-modal music training with CI users may provide clinicians with a better understanding of optimal rehabilitation.

METHODS

Within 3 months, 81 post-lingual deafened adult CI recipients will undergo electrophysiological recordings and a four-week neurologic music therapy multi-modal training randomly assigned to one of three training focusses (pitch, rhythm, and timbre). Pre- and post-tests will analyze behavioral outcomes and apply a novel electrophysiological measurement approach that includes neural tracking to speech and alpha oscillation modulations to the sentence-final-word-identification-and-recall test (SWIR-EEG). Expected outcome: Short-term multi-modal music training will enhance WM and SIN performance in post-lingual deafened adult CI recipients and will be reflected in greater neural tracking and alpha oscillation modulations in prefrontal areas. Prospectively, outcomes could contribute to understanding the relationship between cognitive functioning and SIN besides the technical deficits of the CI. Targeted clinical application of music training for post-lingual deafened adult CI carriers to significantly improve SIN and positively impact the quality of life can be realized.

An Exploration of the Memory Performance in Older Adult Hearing Aid Users on the Integrated Digit-in-Noise Test

This study aimed to preliminarily investigate the associations between performance on the integrated Digit-in-Noise Test (iDIN) and performance on measures of general cognition and working memory (WM). The study recruited 81 older adult hearing aid users between 60 and 95 years of age with bilateral moderate to severe hearing loss. The Chinese version of the Montreal Cognitive Assessment Basic (MoCA-BC) was used to screen older adults for mild cognitive impairment. Speech reception thresholds (SRTs) were measured using 2- to 5-digit sequences of the Mandarin iDIN. The differences in SRT between five-digit and two-digit sequences (SRT5-2), and between five-digit and three-digit sequences (SRT5-3), were used as indicators of memory performance. The results were compared to those from the Digit Span Test and Corsi Blocks Tapping Test, which evaluate WM and attention capacity. SRT5-2 and SRT5-3 demonstrated significant correlations with the three cognitive function tests (rs ranging from -.705 to -.528). Furthermore, SRT5-2 and SRT5-3 were significantly higher in participants who failed the MoCA-BC screening compared to those who passed. The findings show associations between performance on the iDIN and performance on memory tests. However, further validation and exploration are needed to fully establish its effectiveness and efficacy.

On the Feasibility of Using Behavioral Listening Effort Test Methods to Evaluate Auditory Performance in Cochlear Implant Users

Realistic outcome measures that reflect everyday hearing challenges are needed to assess hearing aid and cochlear implant (CI) fitting. Literature suggests that listening effort measures may be more sensitive to differences between hearing-device settings than established speech intelligibility measures when speech intelligibility is near maximum. Which method provides the most effective measurement of listening effort for this purpose is currently unclear. This study aimed to investigate the feasibility of two tests for measuring changes in listening effort in CI users due to signal-to-noise ratio (SNR) differences, as would arise from different hearing-device settings. By comparing the effect size of SNR differences on listening effort measures with test-retest differences, the study evaluated the suitability of these tests for clinical use. Nineteen CI users underwent two listening effort tests at two SNRs (+4 and +8 dB relative to individuals' 50% speech perception threshold). We employed dual-task paradigms-a sentence-final word identification and recall test (SWIRT) and a sentence verification test (SVT)-to assess listening effort at these two SNRs. Our results show a significant difference in listening effort between the SNRs for both test methods, although the effect size was comparable to the test-retest difference, and the sensitivity was not superior to speech intelligibility measures. Thus, the implementations of SVT and SWIRT used in this study are not suitable for clinical use to measure listening effort differences of this magnitude in individual CI users. However, they can be used in research involving CI users to analyze group data.

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

Despite substantial technical advances and wider clinical use, cochlear implant (CI) users continue to report high and elevated listening effort especially under challenging noisy conditions. Among all the objective measures to quantify listening effort, pupillometry is one of the most widely used and robust physiological measures. Previous studies with normally hearing (NH) and hearing-impaired (HI) listeners have shown that the relation between speech performance in noise and listening effort (as measured by peak pupil dilation) is not linear and exhibits an inverted-U shape. However, it is unclear whether the same psychometric relation exists in CI users, and whether individual differences in auditory sensitivity and central cognitive capacity affect this relation. Therefore, we recruited 17 post-lingually deaf CI adults to perform speech-in-noise tasks from 0 to 20 dB SNR with a 4 dB step size. Simultaneously, their pupillary responses and self-reported subjective effort were recorded. To characterize top-down and bottom-up individual variabilities, a spectro-temporal modulation task and a set of cognitive abilities were measured. Clinical word recognition in quiet and Quality of Life (QoL) were also collected. Results showed that at a group level, an inverted-U shape psychometric curve between task difficulty (SNR) and peak pupil dilation (PPD) was not observed. Individual shape of the psychometric curve was significantly associated with some individual factors: CI users with higher clinical word and speech-in-noise recognition showed a quadratic decrease of PPD over increasing SNRs; CI users with better non-verbal intelligence and lower QoL showed smaller average PPD. To summarize, individual differences in CI users had a significant impact on the psychometric relation between pupillary response and task difficulty, hence affecting the interpretation of pupillary response as listening effort (or engagement) at different task difficulty levels. Future research and clinical applications should further characterize the possible effects of individual factors (such as motivation or engagement) in modulating CI users' occurrence of 'tipping point' on their psychometric functions, and develop an individualized method for reliably quantifying listening effort using pupillometry.

The relationship between age, acceptable noise level, and listening effort in middle-aged and older-aged individuals

Objective

The purpose of the study was to evaluate listening effort in adults who experience varied annoyance towards noise.

Materials and methods

Fifty native Kannada-speaking adults aged 41-68 years participated. We evaluated the participant's acceptable noise level while listening to speech. Further, a sentence-final word-identification and recall test at 0 dB SNR (less favorable condition) and 4 dB SNR (relatively favorable condition) was used to assess listening effort. The repeat and recall scores were obtained for each condition.

Results

The regression model revealed that the listening effort increased by 0.6% at 0 dB SNR and by 0.5% at 4 dB SNR with every one-year advancement in age. Listening effort increased by 0.9% at 0 dB SNR and by 0.7% at 4 dB SNR with every one dB change in the value of Acceptable Noise Level (ANL). At 0 dB SNR and 4 dB SNR, a moderate and mild negative correlation was noted respectively between listening effort and annoyance towards noise when the factor age was controlled.

Conclusion

Listening effort increases with age, and its effect is more in less favorable than in relatively favorable conditions. However, if the annoyance towards noise was controlled, the impact of age on listening effort was reduced. Listening effort correlated with the level of annoyance once the age effect was controlled. Furthermore, the listening effort was predicted from the ANL to a moderate degree.

Evaluation of the Benefits of Bilateral Fitting in Bone-Anchored Hearing System Users: Spatial Resolution and Memory for Speech

OBJECTIVES

The purpose of this study was to evaluate the benefits of bilateral implantation for bone-anchored hearing system (BAHS) users in terms of spatial resolution abilities and auditory memory for speech.

DESIGN

This is a prospective, single-center, comparative, single-blinded study where the listeners served as their own control. Twenty-four experienced bone-anchored users with a bilateral conductive or mixed hearing loss participated in the study. After fitting the listeners unilaterally and bilaterally with BAHS sound processor(s) (Ponto 3 SuperPower), spatial resolution was estimated by measuring the minimum audible angle (MAA) to achieve an 80% correct response via a two-alternative-forced choice task (right-left discrimination of noise bursts) in two conditions: both sound processors active (bilateral condition) and only one sound processor active (unilateral condition). In addition, a memory recall test, the Sentence-final Word Identification and Recall (SWIR) test was performed with five lists of seven sentences for each of the two conditions (unilateral and bilateral). Self-reported performance in everyday life with the listener's own sound processors was also evaluated via a questionnaire (the abbreviated version of the Speech, Spatial and Qualities of Hearing scale).

RESULTS

The MAA to discriminate noise bursts improved significantly from 75.04° in the unilateral condition to 3.61° in the bilateral condition ( p < 0.0001). The average improvement in performance was 54.28°. The SWIR test results showed that the listeners could recall, on average, 55.03% of the last words in a list of seven sentences in the unilateral condition and 57.23% in the bilateral condition. While the main effect of condition was not significant, there was a significant interaction between condition and repetition (list), revealing a significantly higher recall performance in the bilateral condition than in the unilateral condition for the second repetition/list out of five (10.2% difference; p = 0.022). Self-reported performance with bilateral BAHS obtained via the Speech, Spatial and Qualities of Hearing scale questionnaire was, on average, 4.4 for speech, 3.7 for spatial, and 5.1 for qualities of hearing. There was no correlation between self-reported performance in everyday life and bilateral performance in the MAA test, while significant correlations were obtained between self-reported performance and recall performance in the SWIR test.

CONCLUSIONS

These results showed a large benefit in spatial resolution for users with symmetric BC thresholds when being fitted with two BAHS, although their self-reported performance with bilateral BAHS in everyday life was rather low. In addition, there was no overall benefit of bilateral fitting on memory for speech, despite observing a benefit in one out of five repetitions of the SWIR test. Performance in the SWIR test was correlated with the users' self-reported performance in everyday life, such that users with higher recall ability reported to achieve better performance in real life. These findings highlight the advantages of bilateral fitting on spatial resolution, although bilaterally fitted BAHS users continue to experience some difficulties in their daily lives, especially when locating sounds, judging distance and movement. More research is needed to support a higher penetration of bilateral BAHS treatment for bilateral conductive and mixed hearing losses.

A decrease in physiological arousal accompanied by stable behavioral performance reflects task habituation

Despite the evidence of a positive relationship between task demands and listening effort, the Framework for Understanding Effortful Listening (FUEL) highlights the important role of arousal on an individual’s choice to engage in challenging listening tasks. Previous studies have interpreted physiological responses in conjunction with behavioral responses as markers of task engagement. The aim of the current study was to investigate the effect of potential changes in physiological arousal, indexed by the pupil baseline, on task engagement over the course of an auditory recall test. Furthermore, the aim was to investigate whether working memory (WM) capacity and the signal-to-noise ratio (SNR) at which the test was conducted had an effect on changes in arousal. Twenty-one adult hearing aid users with mild to moderately severe symmetrical sensorineural hearing loss were included. The pupil baseline was measured during the Sentence-final Word Identification and Recall (SWIR) test, which was administered in a background noise composed of sixteen talkers. The Reading Span (RS) test was used as a measure of WM capacity. The findings showed that the pupil baseline decreased over the course of the SWIR test. However, recall performance remained stable, indicating that the participants maintained the necessary engagement level required to perform the task. These findings were interpreted as a decline in arousal as a result of task habituation. There was no effect of WM capacity or individual SNR level on the change in pupil baseline over time. A significant interaction was found between WM capacity and SNR level on the overall mean pupil baseline. Individuals with higher WM capacity exhibited an overall larger mean pupil baseline at low SNR levels compared to individuals with poorer WM capacity. This may be related to the ability of individuals with higher WM capacity to perform better than individual with poorer WM capacity in challenging listening conditions.

Listening Effort in Cochlear Implant Users: The Effect of Speech Intelligibility, Noise Reduction Processing, and Working Memory Capacity on the Pupil Dilation Response

PURPOSE

This study aimed to evaluate the effect of speech recognition performance, working memory capacity (WMC), and a noise reduction algorithm (NRA) on listening effort as measured with pupillometry in cochlear implant (CI) users while listening to speech in noise.

METHOD

Speech recognition and pupil responses (peak dilation, peak latency, and release of dilation) were measured during a speech recognition task at three speech-to-noise ratios (SNRs) with an NRA in both on and off conditions. WMC was measured with a reading span task. Twenty experienced CI users participated in this study.

RESULTS

With increasing SNR and speech recognition performance, (a) the peak pupil dilation decreased by only a small amount, (b) the peak latency decreased, and (c) the release of dilation after the sentences increased. The NRA had no effect on speech recognition in noise or on the peak or latency values of the pupil response but caused less release of dilation after the end of the sentences. A lower reading span score was associated with higher peak pupil dilation but was not associated with peak latency, release of dilation, or speech recognition in noise.

CONCLUSIONS

In CI users, speech perception is effortful, even at higher speech recognition scores and high SNRs, indicating that CI users are in a chronic state of increased effort in communication situations. The application of a clinically used NRA did not improve speech perception, nor did it reduce listening effort. Participants with a relatively low WMC exerted relatively more listening effort but did not have better speech reception thresholds in noise.

The Effects of Hearing-Aid Amplification and Noise on Conversational Dynamics Between Normal-Hearing and Hearing-Impaired Talkers

There is a long-standing tradition to assess hearing-aid benefits using lab-based speech intelligibility tests. Towards a more everyday-like scenario, the current study investigated the effects of hearing-aid amplification and noise on face-to-face communication between two conversational partners. Eleven pairs, consisting of a younger normal-hearing (NH) and an older hearing-impaired (HI) participant, solved spot-the-difference tasks while their conversations were recorded. In a two-block randomized design, the tasks were solved in quiet or noise, both with and without the HI participant receiving hearing-aid amplification with active occlusion cancellation. In the presence of 70 dB SPL babble noise, participants had fewer, slower, and less well-timed turn-starts, while speaking louder with longer inter-pausal units (IPUs, stretches of continuous speech surrounded by silence) and reducing their articulation rates. All these changes are indicative of increased communication effort. The timing of turn-starts by the HI participants exhibited more variability than that of their NH conversational partners. In the presence of background noise, the timing of turn-starts by the HI participants became even more variable, and their NH partners spoke louder. When the HI participants were provided with hearing-aid amplification, their timing of turn-starts became faster, they increased their articulation rate, and they produced shorter IPUs, all indicating reduced communication effort. In conclusion, measures of the conversational dynamics showed that background noise increased the communication effort, especially for the HI participants, and that providing hearing-aid amplification caused the HI participant to behave more like their NH conversational partner, especially in quiet situations.

A Glimpse of Memory Through the Eyes: Pupillary Responses Measured During Encoding Reflect the Likelihood of Subsequent Memory Recall in an Auditory Free Recall Test

The aim of the current study was to investigate whether task-evoked pupillary responses measured during encoding, individual working memory capacity and noise reduction in hearing aids were associated with the likelihood of subsequently recalling an item in an auditory free recall test combined with pupillometry. Participants with mild to moderately severe symmetrical sensorineural hearing loss (n = 21) were included. The Sentence-final Word Identification and Recall (SWIR) test was administered in a background noise composed of sixteen talkers with noise reduction in hearing aids activated and deactivated. The task-evoked peak pupil dilation (PPD) was measured. The Reading Span (RS) test was used as a measure of individual working memory capacity. Larger PPD at a single trial level was significantly associated with higher likelihood of subsequently recalling a word, presumably reflecting the intensity of attention devoted during encoding. There was no clear evidence of a significant relationship between working memory capacity and subsequent memory recall, which may be attributed to the SWIR test and RS test being administered in different modalities, as well as differences in task characteristics. Noise reduction did not have a significant effect on subsequent memory recall. This may be due to the background noise not having a detrimental effect on attentional processing at the favorable signal-to-noise ratio levels at which the test was conducted.

Postoperative Benefit of Bone Anchored Hearing Systems: Behavioral Performance and Self-Reported Outcomes

Introduction Bone anchored hearing solutions are a well-known option for patients with a conductive, mixed conductive-sensorineural hearing loss and those with single-sided deafness.

Objective The aim of the present study was to evaluate the Ponto bone-anchored hearing system in terms of behavioral performance and self-reported outcomes, by comparing unaided and aided performance (softband and abutment), as well as aided performance with the sound processor on softband (preoperatively) versus abutment (postoperatively).

Methods Fourteen adult bone-anchored candidates, with either a bilateral (n = 12) or unilateral (n = 2) conductive or mixed hearing loss, participated in the present study. Sound-field hearing thresholds were evaluated unaided and aided (softband and abutment). A speech-in-noise test was also performed unaided and aided for two spatial configurations (S0N90; implanted side; S0N90; nonimplanted side). The Glasgow Health Status Inventory and the Speech, Spatial and Quality of sound questionnaires were administered pre- and postsurgery to compare quality of life and perceived unaided and aided performance. Skin reaction (Holgers scores) was evaluated at 15 days, 6 weeks, and 10 weeks after surgery.

Results Significant improvements postoperatively relative to unaided were obtained for sound-field thresholds at all tested frequencies. Additionally, sound-field thresholds were significantly improved with the sound processor on abutment relative to the softband at frequencies > 1 kHz. Improved performance postoperatively relative to unaided was also obtained in the speech-in-noise test and in self-reported outcomes.

Conclusions Improvements in behavioral performance and self-reported outcomes were obtained with the sound processor mounted on abutment.

Investigating Real-World Benefits of High-Frequency Gain in Bone-Anchored Users with Ecological Momentary Assessment and Real-Time Data Logging

Purpose: To compare listening ability (speech reception thresholds) and real-life listening experience in users with a percutaneous bone conduction device (BCD) with two listening programs differing only in high-frequency gain. In situ real-life experiences were recorded with ecological momentary assessment (EMA) techniques combined with real-time acoustical data logging and standard retrospective questionnaires. Methods: Nineteen experienced BCD users participated in this study. They all used a Ponto 4 BCD from Oticon Medical during a 4-week trial period. Environmental data and device parameters (i.e., device usage and volume control) were logged in real-time on an iPhone via a custom iOS research app. At the end of the trial period, subjects filled in APHAB, SSQ, and preference questionnaires. Listening abilities with the two programs were evaluated with speech reception threshold tests. Results: The APHAB and SSQ questionnaires did not reveal any differences between the two listening programs. The EMAs revealed group-level effects, indicating that in speech and noisy listening environments, subjects preferred the default listening program, and found the program with additional high-frequency gain too loud. This finding was corroborated by the volume log—subjects avoided the higher volume control setting and reacted more to changes in environmental sound pressure levels when using the high-frequency gain program. Finally, day-to-day changes in EMAs revealed acclimatization effects in the listening experience for ratings of “sound quality” and “program suitability” of the BCD, but not for ratings of “loudness perception” and “speech understanding”. The acclimatization effect did not differ among the listening programs. Conclusion: Adding custom high-frequency amplification to the BCD target-gain prescription improves speech reception in laboratory tests under quiet conditions, but results in poorer real-life listening experiences due to loudness.

How Do We Allocate Our Resources When Listening and Memorizing Speech in Noise? A Pupillometry Study

OBJECTIVES

Actively following a conversation can be demanding and limited cognitive resources must be allocated to the processing of speech, retaining and encoding the perceived content, and preparing an answer. The aim of the present study was to disentangle the allocation of effort into the effort required for listening (listening effort) and the effort required for retention (memory effort) by means of pupil dilation.

DESIGN

Twenty-five normal-hearing German speaking participants underwent a sentence final word identification and recall test, while pupillometry was conducted. The participants' task was to listen to a sentence in four-talker babble background noise and to repeat the final word afterward. At the end of a list of sentences, they were asked to recall as many of the final words as possible. Pupil dilation was recorded during different list lengths (three sentences versus six sentences) and varying memory load (recall versus no recall). Additionally, the effect of a noise reduction algorithm on performance, listening effort, and memory effort was evaluated.

RESULTS

We analyzed pupil dilation both before each sentence (sentence baseline) as well as the dilation in response to each sentence relative to the sentence baseline (sentence dilation). The pupillometry data indicated a steeper increase of sentence baseline under recall compared to no recall, suggesting higher memory effort due to memory processing. This increase in sentence baseline was most prominent toward the end of the longer lists, that is, during the second half of six sentences. Without a recall task, sentence baseline declined over the course of the list. Noise reduction appeared to have a significant influence on effort allocation for listening, which was reflected in generally decreased sentence dilation.

CONCLUSION

Our results showed that recording pupil dilation in a speech identification and recall task provides valuable insights beyond behavioral performance. It is a suitable tool to disentangle the allocation of effort to listening versus memorizing speech.

Recall of Reverberant Speech in Quiet and Four-Talker Babble Noise

Using behavioral evaluation of free recall performance, we investigated whether reverberation and/or noise affected memory performance in normal-hearing adults. Thirty-four participants performed a free-recall task in which they were instructed to repeat the initial word after each sentence and to remember the target words after each list of seven sentences, in a 2 (reverberation) × 2 (noise) factorial design. Pupil dilation responses (baseline and peak pupil dilation) were also recorded sentence-by-sentence while the participants were trying to remember the target words. In noise, speech was presented at an easily audible level using an individualized signal-to-noise ratio (95% speech intelligibility). As expected, recall performance was significantly lower in the noisy environment than in the quiet condition. Regardless of noise interference or reverberation, sentence- baseline values gradually increased with an increase in the number of words to be remembered for a subsequent free-recall task. Long reverberation time had no significant effect on memory retrieval of verbal stimuli or pupillary responses during encoding.

Three New Outcome Measures That Tap Into Cognitive Processes Required for Real-Life Communication

To increase the ecological validity of outcomes from laboratory evaluations of hearing and hearing devices, it is desirable to introduce more realistic outcome measures in the laboratory. This article presents and discusses three outcome measures that have been designed to go beyond traditional speech-in-noise measures to better reflect realistic everyday challenges. The outcome measures reviewed are: the Sentence-final Word Identification and Recall (SWIR) test that measures working memory performance while listening to speech in noise at ceiling performance; a neural tracking method that produces a quantitative measure of selective speech attention in noise; and pupillometry that measures changes in pupil dilation to assess listening effort while listening to speech in noise. According to evaluation data, the SWIR test provides a sensitive measure in situations where speech perception performance might be unaffected. Similarly, pupil dilation has also shown sensitivity in situations where traditional speech-in-noise measures are insensitive. Changes in working memory capacity and effort mobilization were found at positive signal-to-noise ratios (SNR), that is, at SNRs that might reflect everyday situations. Using stimulus reconstruction, it has been demonstrated that neural tracking is a robust method at determining to what degree a listener is attending to a specific talker in a typical cocktail party situation. Using both established and commercially available noise reduction schemes, data have further shown that all three measures are sensitive to variation in SNR. In summary, the new outcome measures seem suitable for testing hearing and hearing devices under more realistic and demanding everyday conditions than traditional speech-in-noise tests.

Development of an Australian behavioural method for assessing listening task difficulty at high speech intelligibility levels

OBJECTIVE

To develop and validate an Australian version of a behavioural test for assessing listening task difficulty at high speech intelligibility levels.

DESIGN

In the SWIR-Aus test, listeners perform two tasks: identify the last word of each of seven sentences in a list and recall the identified words after each list. First, the test material was developed by creating seven-sentence lists with similar final-word features. Then, for the validation, participant's performance on the SWIR-Aus test was compared when a binary mask noise reduction algorithm was on and off.

STUDY SAMPLE

All participants in this study had normal hearing thresholds. Nine participants (23.8-56.0 years) participated in the characterisation of the speech material. Another thirteen participants (18.4-59.1 years) participated in a pilot test to determine the SNR to use at the validation stage. Finally, twenty-four new participants (20.0-56.9 years) participated in the validation of the test.

RESULTS

The results of the validation of the test showed that recall and identification scores were significantly better when the binary mask noise reduction algorithm was on compared to off.

CONCLUSIONS

The SWIR-Aus test was developed using Australian speech material and can be used for assessing task difficulty at high speech intelligibility levels.

The Effects of Task Difficulty Predictability and Noise Reduction on Recall Performance and Pupil Dilation Responses

OBJECTIVES

Communication requires cognitive processes which are not captured by traditional speech understanding tests. Under challenging listening situations, more working memory resources are needed to process speech, leaving fewer resources available for storage. The aim of the current study was to investigate the effect of task difficulty predictability, that is, knowing versus not knowing task difficulty in advance, and the effect of noise reduction on working memory resource allocation to processing and storage of speech heard in background noise. For this purpose, an "offline" behavioral measure, the Sentence-Final Word Identification and Recall (SWIR) test, and an "online" physiological measure, pupillometry, were combined. Moreover, the outcomes of the two measures were compared to investigate whether they reflect the same processes related to resource allocation.

DESIGN

Twenty-four experienced hearing aid users with moderate to moderately severe hearing loss participated in this study. The SWIR test and pupillometry were measured simultaneously with noise reduction in the test hearing aids activated and deactivated in a background noise composed of four-talker babble. The task of the SWIR test is to listen to lists of sentences, repeat the last word immediately after each sentence and recall the repeated words when the list is finished. The sentence baseline dilation, which is defined as the mean pupil dilation before each sentence, and task-evoked peak pupil dilation (PPD) were analyzed over the course of the lists. The task difficulty predictability was manipulated by including lists of three, five, and seven sentences. The test was conducted over two sessions, one during which the participants were informed about list length before each list (predictable task difficulty) and one during which they were not (unpredictable task difficulty).

RESULTS

The sentence baseline dilation was higher when task difficulty was unpredictable compared to predictable, except at the start of the list, where there was no difference. The PPD tended to be higher at the beginning of the list, this pattern being more prominent when task difficulty was unpredictable. Recall performance was better and sentence baseline dilation was higher when noise reduction was on, especially toward the end of longer lists. There was no effect of noise reduction on PPD.

CONCLUSIONS

Task difficulty predictability did not have an effect on resource allocation, since recall performance was similar independently of whether task difficulty was predictable or unpredictable. The higher sentence baseline dilation when task difficulty was unpredictable likely reflected a difference in the recall strategy or higher degree of task engagement/alertness or arousal. Hence, pupillometry captured processes which the SWIR test does not capture. Noise reduction frees up resources to be used for storage of speech, which was reflected in the better recall performance and larger sentence baseline dilation toward the end of the list when noise reduction was on. Thus, both measures captured different temporal aspects of the same processes related to resource allocation with noise reduction on and off.

Disentangling listening effort and memory load beyond behavioural evidence: Pupillary response to listening effort during a concurrent memory task

Recent research has demonstrated that pupillometry is a robust measure for quantifying listening effort. However, pupillary responses in listening situations where multiple cognitive functions are engaged and sustained over a period of time remain hard to interpret. This limits our conceptualisation and understanding of listening effort in realistic situations, because rarely in everyday life are people challenged by one task at a time. Therefore, the purpose of this experiment was to reveal the dynamics of listening effort in a sustained listening condition using a word repeat and recall task. Words were presented in quiet and speech-shaped noise at different signal-to-noise ratios (SNR): 0dB, 7dB, 14dB and quiet. Participants were presented with lists of 10 words, and required to repeat each word after its presentation. At the end of the list, participants either recalled as many words as possible or moved on to the next list. Simultaneously, their pupil dilation was recorded throughout the whole experiment. When only word repeating was required, peak pupil dilation (PPD) was bigger in 0dB versus other conditions; whereas when recall was required, PPD showed no difference among SNR levels and PPD in 0dB was smaller than repeat-only condition. Baseline pupil diameter and PPD followed different variation patterns across the 10 serial positions within a block for conditions requiring recall: baseline pupil diameter built up progressively and plateaued in the later positions (but shot up when listeners were recalling the previously heard words from memory); PPD decreased at a pace quicker than in repeat-only condition. The current findings demonstrate that additional cognitive load during a speech intelligibility task could disturb the well-established relation between pupillary response and listening effort. Both the magnitude and temporal pattern of task-evoked pupillary response differ greatly in complex listening conditions, urging for more listening effort studies in complex and realistic listening situations.

Effects of Noise and Serial Position on Free Recall of Spoken Words and Pupil Dilation during Encoding in Normal-Hearing Adults

This preliminary study assessed the effects of noise and stimulus presentation order on recall of spoken words and recorded pupil sizes while normal-hearing listeners were trying to encode a series of words for a subsequent recall task. In three listening conditions (stationary noise in Experiment 1; quiet versus four-talker babble in Experiment 2), participants were assigned to remember as many words as possible to recall them in any order after each list of seven sentences. In the two noise conditions, lists of sentences fixed at 65 dB SPL were presented at an easily audible level via a loudspeaker. Reading span (RS) scores were used as a grouping variable, based on a median split. The primacy effect was present apart from the noise interference, and the high-RS group significantly outperformed the low-RS group at free recall measured in the quiet and four-talker babble noise conditions. RS scores were positively correlated with free-recall scores. In both quiet and four-talker babble noise conditions, sentence baselines after correction to the initial stimulus baseline increased significantly with increasing memory load. Larger sentence baselines but smaller peak pupil dilations seemed to be associated with noise interruption. The analysis method of pupil dilation used in this study is likely to provide a more thorough understanding of how listeners respond to a later recall task in comparison with previously used methods. Further studies are needed to confirm the applicability of our method in people with impaired hearing using multiple repetitions to estimate the allocation of relevant cognitive resources.

The Cost of Intrinsic and Extrinsic Cognitive Demands on Auditory Functioning in Older Adults With Normal Hearing or Using Hearing Aids

OBJECTIVES

We investigated the impact of both intrinsic and extrinsic cognitive demands on auditory and secondary task performance in older adults with normal hearing (NH) and adults using hearing aids (HAs) in an ecologically relevant listening environment.

DESIGN

Fifteen adults with NH and 15 adults using HAs (60 to 72 years of age) were recruited to perform the "Audiovisual True-to-Life Assessment of Auditory Rehabilitation"-paradigm (AVATAR), which combines an auditory-visual speech-in-noise task with three secondary tasks on either auditory localization or visual short-term memory in a preload multitask paradigm. Intrinsic demands were altered by presenting speech either at equivalent speech accuracy levels of 50% correct (SPIN50%) or equivalent speech-to-noise ratios of +5dB SNR (SPIN+5dB). We manipulated the amount of extrinsic cognitive demands by including one (dual condition) or three secondary tasks (quadruple condition). Performance decrements on the secondary tasks were considered to reflect an increase in resource allocation to speech understanding and thus an increase in listening effort. In addition, we administered a cognitive test battery as well as a questionnaire on self-reported hearing difficulties and subjective measures of effort and motivation.

RESULTS

Speech understanding and secondary task performance on the visual short-term memory task were lower in the SPIN50% condition compared to SPIN+5dB. Whereas speech understanding at SPIN50% was equally high in the dual and quadruple conditions, the quadruple condition resulted in lower secondary task performance on the visual short-term memory task, higher levels of self-reported effort, and lower motivation compared to the dual-task condition. The same was true for experimental conditions at SPIN+5dB. Additionally, adults with NH outperformed adults using HAs on speech understanding, auditory localization, and self-reported hearing abilities, but no group differences were observed on secondary task costs or cognitive measures.

CONCLUSIONS

This study showed that, irrespective of the hearing status of the listener, speech performance was not affected by the amount of extrinsic cognitive demands, but was worse and required more effort under conditions with a more negative SNR. Also, increasing the extrinsic cognitive demands resulted in lower performance on one of the secondary tasks, suggesting that more complex listening environments require more effort. Although adults with NH outperformed HA users on speech understanding and auditory localization, the two groups did not differ with respect to secondary task costs.

An exploratory Study of EEG Alpha Oscillation and Pupil Dilation in Hearing-Aid Users During Effortful listening to Continuous Speech

Individuals with hearing loss allocate cognitive resources to comprehend noisy speech in everyday life scenarios. Such a scenario could be when they are exposed to ongoing speech and need to sustain their attention for a rather long period of time, which requires listening effort. Two well-established physiological methods that have been found to be sensitive to identify changes in listening effort are pupillometry and electroencephalography (EEG). However, these measurements have been used mainly for momentary, evoked or episodic effort. The aim of this study was to investigate how sustained effort manifests in pupillometry and EEG, using continuous speech with varying signal-to-noise ratio (SNR). Eight hearing-aid users participated in this exploratory study and performed a continuous speech-in-noise task. The speech material consisted of 30-second continuous streams that were presented from loudspeakers to the right and left side of the listener (±30° azimuth) in the presence of 4-talker background noise (+180° azimuth). The participants were instructed to attend either to the right or left speaker and ignore the other in a randomized order with two different SNR conditions: 0 dB and -5 dB (the difference between the target and the competing talker). The effects of SNR on listening effort were explored objectively using pupillometry and EEG. The results showed larger mean pupil dilation and decreased EEG alpha power in the parietal lobe during the more effortful condition. This study demonstrates that both measures are sensitive to changes in SNR during continuous speech.

The effects of task difficulty, background noise and noise reduction on recall

OBJECTIVE

In the present study, we investigated whether varying the task difficulty of the Sentence-Final Word Identification and Recall (SWIR) Test has an effect on the benefit of noise reduction, as well as whether task difficulty predictability affects recall. The relationship between working memory and recall was examined.

DESIGN

Task difficulty was manipulated by varying the list length with noise reduction on and off in competing speech and speech-shaped noise. Half of the participants were informed about list length in advance. Working memory capacity was measured using the Reading Span.

STUDY SAMPLE

Thirty-two experienced hearing aid users with moderate sensorineural hearing loss.

RESULTS

Task difficulty did not affect the noise reduction benefit and task difficulty predictability did not affect recall. Participants may have employed a different recall strategy when task difficulty was unpredictable and noise reduction off. Reading Span scores positively correlated with the SWIR test. Noise reduction improved recall in competing speech.

CONCLUSIONS

The SWIR test with varying list length is suitable for detecting the benefit of noise reduction. The correlation with working memory suggests that the SWIR test could be modified to be adaptive to individual cognitive capacity. The results on noise and noise reduction replicate previous findings.

Ten years of experience with the Ponto bone-anchored hearing system-A systematic literature review

Background

Bone‐anchored hearing systems (BAHSs) are widely used for hearing rehabilitation and are indicated in cases of conductive and mixed hearing loss and in single‐sided deafness. The Ponto system, that is one available option, has been on the market since 2009.

Objective of review

The aim of this study is to systematically review the literature reporting on the Ponto system, with regard to audiological and surgical outcomes and patient's quality‐of‐life scores.

Type of review

A systematic literature search was performed in the PubMed database 2009‐July 2019.

Search strategy

Search term: ((osseointegrated hearing aid) OR (bone conduction implant) OR (bone anchored hearing) OR BAHA OR BAHS OR BAHI). Pre‐defined inclusion and exclusion criteria were applied.

Evaluation method

English‐language articles reporting original clinical data (audiological, surgical or quality‐of‐life outcomes) on the Ponto system were included.

Articles reporting on Ponto and another BAHS system where the results on Ponto constituted less than 50% of the patient population or including only results on testband or softband devices were excluded.

Results

Audiological outcomes were discussed in 20 publications. Improvement against the unaided thresholds was demonstrated. The functional improvement was on average 33.9 dB. The effective gain or remaining air‐bone gap was on average 6.7 dB. All evaluated data showed aided speech reception thresholds significantly below normal speech level. Twenty‐seven publications reported surgical and follow‐up data for the Ponto system. Implant survival was 97.7%, adverse skin reactions (Holgers ≥ 2) were 5% across visits and 15% across patients. No complications were life‐threatening, causing permanent disability/damage or requiring a hospitalisation. Five studies reported quality of life using the Glasgow benefit inventory, 98% reported an improvement when analysing the score on an individual level.

Conclusions

The outcomes of this systematic review confirm that percutaneous systems provide consistent audiological benefits and improved quality of life for patients. Further, the review demonstrates that the percutaneous systems are safe, with relatively low complication rates. Skin‐related complications are the most common complication type and are experienced by approximately one patient out of seven, or in less than one of 20 follow‐up visits.

Bone Conduction Amplification in Children: Stimulation via a Percutaneous Abutment versus a Transcutaneous Softband

OBJECTIVES

Research suggests that the speech perception of children using bone conduction amplification improves if the device is coupled to an implanted abutment rather than to a softband. The purpose of the present study was to determine if the benefit of direct stimulation via an abutment is limited to small improvements in speech perception or if similar or greater benefits occur for other auditory tasks important for learning and communication.

DESIGN

Fourteen children (7 to 15 years of age) with bilateral conductive and three children with unilateral conductive or sensorineural hearing loss were enrolled. Each child completed four tasks while using a bone conduction device coupled to an implanted abutment and with the device coupled to a softband. The two devices were worn at the same time and activated one at a time for testing. The children completed four tasks under each coupling condition: (a) a traditional word recognition task, (b) an auditory lexical decision task in which the children repeated aloud, and indicated the category of, real and nonsense words, (c) a nonsense-word detection task which required the children to identify nonsense words within short sentences, and (d) a rapid word learning task in which the children learned to associate nonsense words with novel images.

RESULTS

Regression analyses revealed that age, duration of device use, in-situ hearing thresholds, or device output did not account for a significant portion of the variability in performance for any of the four tasks. Repeated-measures analysis of variance revealed significant increases in word recognition with the abutment as well as significantly better performance for the lexical decision and word learning tasks. The data indicated that the children with the poorest performance with the softband tended to benefit most with the abutment. Also, the younger children showed improved performance for more tasks with the abutment than the older children. No difference between coupling conditions was observed for nonsense-word detection.

CONCLUSIONS

The improved recognition of familiar words, categorization and repetition of nonsense words, and speed of word learning with the abutment suggests that direct stimulation provides a higher-quality signal than indirect stimulation through a softband. Because these processes are important for vocabulary acquisition and language development, children may experience long-term benefits of direct stimulation for academic, social, and vocational purposes in addition to immediate improvement in communication.

Auditory Working Memory Explains Variance in Speech Recognition in Older Listeners Under Adverse Listening Conditions

Introduction

Older listeners have difficulty understanding speech in unfavorable listening conditions. To compensate for acoustic degradation, cognitive processing skills, such as working memory, need to be engaged. Despite prior findings on the association between working memory and speech recognition in various listening conditions, it is not yet clear whether the modality of stimuli presentation for working memory tasks should be auditory or visual. Given the modality-specific characteristics of working memory, we hypothesized that auditory working memory capacity could predict speech recognition performance in adverse listening conditions for older listeners and that the contribution of auditory working memory to speech recognition would depend on the task and listening condition.

Methods

Seventy-six older listeners and twenty younger listeners completed four kinds of auditory working memory tasks, including digit and speech span tasks, and sentence recognition tasks in four different listening conditions having multi-talker noise and time-compression. For older listeners, cognitive function was screened using the Mini-Mental Status Examination, and audibility was assured.

Results

Auditory working memory, as measured by listening span, significantly predicted speech recognition performance in adverse listening conditions for older listeners. A linear regression model showed speech recognition performance for older listeners could be explained by auditory working memory whilst controlling for the impact of age and hearing sensitivity.

Discussion

Measuring working memory in the auditory modality facilitated explaining the variance in speech recognition in adverse listening conditions for older listeners. The linguistic features and the complexity of the auditory stimuli may affect the association between working memory and speech recognition performance.

Conclusion

We demonstrated the contribution of auditory working memory to speech recognition in unfavorable listening conditions in older populations. Taking the modality-specific characteristics of working memory into account may be a key to better understand the difficulty in speech recognition in daily listening conditions for older listeners.

Selected Cognitive Factors Associated with Individual Variability in Clinical Measures of Speech Recognition in Noise Amplified by Fast-Acting Compression Among Hearing Aid Users

Objective:

Previous work examining speech recognition in more challenging listening environments has revealed a large variability in both persons with normal and hearing impairments. Although this is clinically very important, up to now, no consensus has been reached about which factors may provide better explanation for the existing individual variability in speech recognition ability among hearing aid users, when speech signal is degraded. This study aimed to examine hearing-sensitivity skills and cognitive ability differences between listeners with good and poor speech recognition abilities.

Materials and Methods:

A total of 195 experienced hearing aid users (33–80 years) were grouped by higher or lower speech recognition ability based on their performance on the Hagerman sentences task in multi-talker babble using fast-acting compression algorithm. They completed a battery of cognitive abilities tests, hearing-in-noise and the auditory thresholds test.

Results:

The results showed that the two groups did differ significantly overall on cognitive abilities tests like working memory, cognitive processing speed and attentional shifting, but not on the attentional inhibitory test and non-verbal intelligence test.

Conclusions:

Listeners with poor compared to those with better speech recognition abilities exhibit poorer cognitive abilities, which place them in a disadvantaged position, and /or more susceptible to signal modifications (as a result of fast-acting compression signal processing), resulting in limited benefits from hearing aids strategies. The findings may have implications for hearing aid signal processing strategies selection in rehabilitations.

Speech Perception in Noise and Listening Effort of Older Adults With Nonlinear Frequency Compression Hearing Aids

OBJECTIVES

The purpose of this laboratory-based study was to compare the efficacy of two hearing aid fittings with and without nonlinear frequency compression, implemented within commercially available hearing aids. Previous research regarding the utility of nonlinear frequency compression has revealed conflicting results for speech recognition, marked by high individual variability. Individual differences in auditory function and cognitive abilities, specifically hearing loss slope and working memory, may contribute to aided performance. The first aim of the study was to determine the effect of nonlinear frequency compression on aided speech recognition in noise and listening effort using a dual-task test paradigm. The hypothesis, based on the Ease of Language Understanding model, was that nonlinear frequency compression would improve speech recognition in noise and decrease listening effort. The second aim of the study was to determine if listener variables of hearing loss slope, working memory capacity, and age would predict performance with nonlinear frequency compression.

DESIGN

A total of 17 adults (age, 57-85 years) with symmetrical sensorineural hearing loss were tested in the sound field using hearing aids fit to target (NAL-NL2). Participants were recruited with a range of hearing loss severities and slopes. A within-subjects, single-blinded design was used to compare performance with and without nonlinear frequency compression. Speech recognition in noise and listening effort were measured by adapting the Revised Speech in Noise Test into a dual-task paradigm. Participants were required trial-by-trial to repeat the last word of each sentence presented in speech babble and then recall the sentence-ending words after every block of six sentences. Half of the sentences were rich in context for the recognition of the final word of each sentence, and half were neutral in context. Extrinsic factors of sentence context and nonlinear frequency compression were manipulated, and intrinsic factors of hearing loss slope, working memory capacity, and age were measured to determine which participant factors were associated with benefit from nonlinear frequency compression.

RESULTS

On average, speech recognition in noise performance significantly improved with the use of nonlinear frequency compression. Individuals with steeply sloping hearing loss received more recognition benefit. Recall performance also significantly improved at the group level, with nonlinear frequency compression revealing reduced listening effort. The older participants within the study cohort received less recall benefit than the younger participants. The benefits of nonlinear frequency compression for speech recognition and listening effort did not correlate with each other, suggesting separable sources of benefit for these outcome measures.

CONCLUSIONS

Improvements of speech recognition in noise and reduced listening effort indicate that adult hearing aid users can receive benefit from nonlinear frequency compression in a noisy environment, with the amount of benefit varying across individuals and across outcome measures. Evidence supports individualized selection of nonlinear frequency compression, with results suggesting benefits in speech recognition for individuals with steeply sloping hearing losses and in listening effort for younger individuals. Future research is indicated with a larger data set on the dual-task paradigm as a potential cognitive outcome measure.

Conversational speech levels and signal-to-noise ratios in realistic acoustic conditions

Estimating the basic acoustic parameters of conversational speech in noisy real-world conditions has been an elusive task in hearing research. Nevertheless, these data are essential ingredients for speech intelligibility tests and fitting rules for hearing aids. Previous surveys did not provide clear methodology for their acoustic measurements and setups, were opaque about their samples, or did not control for distance between the talker and listener, even though people are known to adapt their distance in noisy conversations. In the present study, conversations were elicited between pairs of people by asking them to play a collaborative game that required them to communicate. While performing this task, the subjects listened to binaural recordings of different everyday scenes, which were presented to them at their original sound pressure level (SPL) via highly open headphones. Their voices were recorded separately using calibrated headset microphones. The subjects were seated inside an anechoic chamber at 1 and 0.5 m distances. Precise estimates of realistic speech levels and signal-to-noise ratios (SNRs) were obtained for the different acoustic scenes, at broadband and third octave levels. It is shown that with acoustic background noise at above approximately 69 dB SPL at 1 m distance, or 75 dB SPL at 0.5 m, the average SNR can become negative. It is shown through interpolation of the two conditions that if the conversation partners would have been allowed to optimize their positions by moving closer to each other, then positive SNRs should be only observed above 75 dB SPL. The implications of the results on speech tests and hearing aid fitting rules are discussed.

Impact of SNR, masker type and noise reduction processing on sentence recognition performance and listening effort as indicated by the pupil dilation response

Recent studies have shown that activating the noise reduction scheme in hearing aids results in a smaller peak pupil dilation (PPD), indicating reduced listening effort, at 50% and 95% correct sentence recognition with a 4-talker masker. The objective of this study was to measure the effect of the noise reduction scheme (on or off) on PPD and sentence recognition across a wide range of signal-to-noise ratios (SNRs) from +16 dB to -12 dB and two masker types (4-talker and stationary noise). Relatively low PPDs were observed at very low (-12 dB) and very high (+16 dB to +8 dB) SNRs presumably due to 'giving up' and 'easy listening', respectively. The maximum PPD was observed with SNRs at approximately 50% correct sentence recognition. Sentence recognition with both masker types was significantly improved by the noise reduction scheme, which corresponds to the shift in performance from SNR function at approximately 5 dB toward a lower SNR. This intelligibility effect was accompanied by a corresponding effect on the PPD, shifting the peak by approximately 4 dB toward a lower SNR. In addition, with the 4-talker masker, when the noise reduction scheme was active, the PPD was smaller overall than that when the scheme was inactive. We conclude that with the 4-talker masker, noise reduction scheme processing provides a listening effort benefit in addition to any effect associated with improved intelligibility. Thus, the effect of the noise reduction scheme on listening effort incorporates more than can be explained by intelligibility alone, emphasizing the potential importance of measuring listening effort in addition to traditional speech reception measures.

Autonomic Nervous System Reactivity During Speech Repetition Tasks: Heart Rate Variability and Skin Conductance

Cognitive and emotional challenges may elicit a physiological stress response that can include arousal of the sympathetic nervous system (fight or flight response) and withdrawal of the parasympathetic nervous system (responsible for recovery and rest). This article reviews studies that have used measures of electrodermal activity (skin conductance) and heart rate variability (HRV) to index sympathetic and parasympathetic activity during auditory tasks. In addition, the authors present results from a new study with normal-hearing listeners examining the effects of speaking rate on changes in skin conductance and high-frequency HRV (HF-HRV). Sentence repetition accuracy for normal and fast speaking rates was measured in noise using signal to noise ratios that were adjusted to approximate 80% accuracy (+3 dB fast rate; 0 dB normal rate) while monitoring skin conductance and HF-HRV activity. A significant increase in skin conductance level (reflecting sympathetic nervous system arousal) and a decrease in HF-HRV (reflecting parasympathetic nervous system withdrawal) were observed with an increase in speaking rate indicating sensitivity of both measures to increased task demand. Changes in psychophysiological reactivity with increased auditory task demand may reflect differences in listening effort, but other person-related factors such as motivation and stress may also play a role. Further research is needed to understand how psychophysiological activity during listening tasks is influenced by the acoustic characteristics of stimuli, task demands, and by the characteristics and emotional responses of the individual.

Listening and Learning: Cognitive Contributions to the Rehabilitation of Older Adults With and Without Audiometrically Defined Hearing Loss

Here, we describe some of the ways in which aging negatively affects the way sensory input is transduced and processed within the aging brain and how cognitive work is involved when listening to a less-than-perfect signal. We also describe how audiologic rehabilitation, including hearing aid amplification and listening training, is used to reduce the amount of cognitive resources required for effective auditory communication and conclude with an example of how listening effort is being studied in research laboratories for the purpose(s) of informing clinical practice.