Effect of speaker age on speech recognition and perceived listening effort in older adults with hearing loss

The impact of a speaker's voice quality on auditory perception and cognition: a behavioral and subjective approach

Introduction

Our voice is key for conveying information and knowledge to others during verbal communication. However, those who heavily depend on their voice, such as teachers and university professors, often develop voice problems, signaled by hoarseness. The aim of this study was to investigate the effect of hoarseness on listeners' memory for auditory-verbal information, listening effort, and listening impression.

Methods

Forty-eight normally hearing adults performed two memory tasks that were auditorily presented in varied voice quality (typical vs. hoarse). The tasks were Heard Text Recall, as part of a dual-task paradigm, and auditory Verbal Serial Recall (aVSR). Participants also completed a listening impression questionnaire for both voice qualities. Behavioral measures of memory for auditory-verbal information and listening effort were performance and response time. Subjective measures of listening effort and other aspects of listening impression were questionnaire rating scores.

Results

Results showed that, except for the aVSR, behavioral outcomes did not vary with the speaker's voice quality. Regarding the aVSR, we found a significant interaction between voice quality and trial, indicating that participants' recall performance dropped in the beginning of the task in the hoarse-voice condition but not in the typical-voice condition, and then increased again toward the end. Results from the listening impression questionnaire showed that listening to the hoarse voice resulted in significantly increased perceived listening effort, greater annoyance and poorer self-reported performance.

Discussion

These findings suggest that hoarseness can, at least subjectively, compromise effective listening. Vocal health may be particularly important in the educational context, where listening and learning are closely linked.

Familiar and unfamiliar speaker recognition assessment and system emulation for cochlear implant users

In the area of speech processing, human speaker identification under naturalistic environments is a challenging task, especially for hearing-impaired individuals with cochlear implants (CIs) or hearing aids (HAs). Motivated by the fact that electrodograms reflect direct CI stimulation of input audio, this study proposes a speaker identification (ID) investigation using two-dimensional electrodograms constructed from the responses of a CI auditory system to emulate CI speaker ID capabilities. Features are extracted from electrodograms through an identity vector (i-vector) framework to train and generate identity models for each speaker using a Gaussian mixture model-universal background model followed by probabilistic linear discriminant analysis. To validate the proposed system, perceptual speaker ID for 20 normal hearing (NH) and seven CI listeners was evaluated with a total of 41 different speakers and compared with the scores from the proposed system. A one-way analysis of variance showed that the proposed system can reliably predict the speaker ID capability of CI (F[1,10] = 0.18, p = 0.68) and NH (F[1,20] = 0, p = 0.98) listeners in naturalistic environments. The impact of speaker familiarity is also addressed, and the results show a reduced performance for speaker recognition by CI subjects using their CI processor, highlighting limitations of current speech processing strategies used in CIs/HAs.

Cognitive Predictors of Perception and Adaptation to Dysarthric Speech in Young Adult Listeners

PURPOSE

Although recruitment of cognitive-linguistic resources to support dysarthric speech perception and adaptation is presumed by theoretical accounts of effortful listening and supported by cross-disciplinary empirical findings, prospective relationships have received limited attention in the disordered speech literature. This study aimed to examine the predictive relationships between cognitive-linguistic parameters and intelligibility outcomes associated with familiarization with dysarthric speech in young adult listeners.

METHOD

A cohort of 156 listener participants between the ages of 18 and 50 years completed a three-phase perceptual training protocol (pretest, training, and posttest) with one of three speakers with dysarthria. Additionally, listeners completed the National Institutes of Health Toolbox Cognition Battery to obtain measures of the following cognitive-linguistic constructs: working memory, inhibitory control of attention, cognitive flexibility, processing speed, and vocabulary knowledge.

RESULTS

Elastic net regression models revealed that select cognitive-linguistic measures and their two-way interactions predicted both initial intelligibility and intelligibility improvement of dysarthric speech. While some consistency across models was shown, unique constellations of select cognitive factors and their interactions predicted initial intelligibility and intelligibility improvement of the three different speakers with dysarthria.

CONCLUSIONS

Current findings extend empirical support for theoretical models of speech perception in adverse listening conditions to dysarthric speech signals. Although predictive relationships were complex, vocabulary knowledge, working memory, and cognitive flexibility often emerged as important variables across the models.

The Involvement of Listening Effort in Explaining Bilingual Listening Under Adverse Listening Conditions

The current review examines listening effort to uncover how it is implicated in bilingual performance under adverse listening conditions. Various measures of listening effort, including physiological, behavioral, and subjective measures, have been employed to examine listening effort in bilingual children and adults. Adverse listening conditions, stemming from environmental factors, as well as factors related to the speaker or listener, have been examined. The existing literature, although relatively limited to date, points to increased listening effort among bilinguals in their nondominant second language (L2) compared to their dominant first language (L1) and relative to monolinguals. Interestingly, increased effort is often observed even when speech intelligibility remains unaffected. These findings emphasize the importance of considering listening effort alongside speech intelligibility. Building upon the insights gained from the current review, we propose that various factors may modulate the observed effects. These include the particular measure selected to examine listening effort, the characteristics of the adverse condition, as well as factors related to the particular linguistic background of the bilingual speaker. Critically, further research is needed to better understand the impact of these factors on listening effort. The review outlines avenues for future research that would promote a comprehensive understanding of listening effort in bilingual individuals.

Measuring the Subjective Cost of Listening Effort Using a Discounting Task

Purpose Objective measures of listening effort have been gaining prominence, as they provide metrics to quantify the difficulty of understanding speech under a variety of circumstances. A key challenge has been to develop paradigms that enable the complementary measurement of subjective listening effort in a quantitatively precise manner. In this study, we introduce a novel decision-making paradigm to examine age-related and individual differences in subjective effort during listening. Method Older and younger adults were presented with spoken sentences mixed with speech-shaped noise at multiple signal-to-noise ratios (SNRs). On each trial, subjects were offered the choice between completing an easier listening trial (presented at +20 dB SNR) for a smaller monetary reward and completing a harder listening trial (presented at either +4, 0, -4, -8, or -12 dB SNR) for a greater monetary reward. By varying the amount of the reward offered for the easier option, the subjective value of performing effortful listening trials at each SNR could be assessed. Results Older adults discounted the value of effortful listening to a greater degree than young adults, opting to accept less money in order to avoid more difficult SNRs. Additionally, older adults with poorer hearing and smaller working memory capacities were more likely to choose easier trials; however, in younger adults, no relationship with hearing or working memory was found. Self-reported measures of economic status did not affect these relationships. Conclusions These findings suggest that subjective listening effort depends on factors including, but not necessarily limited to, hearing and working memory. Additionally, this study demonstrates that economic decision-making paradigms can be a useful approach for assessing subjective listening effort and may prove beneficial in future research.

An exploratory model of speech intelligibility for healthy aging based on phonatory and articulatory measures

PURPOSE

The aims of the current study were to determine age-related changes to the phonatory and articulatory subsystems and to investigate an exploratory model of intelligibility for healthy aging based on phonatory and articulatory measures.

METHOD

Fifteen healthy, older adults (55-81 years) and 15 younger adults (20-35 years) participated in instrumental assessments of the phonatory (aerodynamic, acoustic) and articulatory (kinematic) subsystems. Speech intelligibility was determined by five listeners during multi-talker babble.

RESULTS

Older adults displayed shorter maximum phonation time, greater airflow during sentence reading, and lower cepstral peak prominence (CPP) and CPP SD. Additionally, older adults had slower tongue movement speed than younger adults. Speech intelligibility was also significantly reduced in the older group. A generalized estimating equations model combining phonatory and articulatory measures showed that CPP SD, low/high (L/H) spectral ratio mean and SD, Cepstral Spectral Index of Dysphonia (CSID), and maximum tongue movement speed were significant contributors to intelligibility changes in older individuals. While L/H mean and SD and CSID displayed an inverse relationship with intelligibility, CPP SD and maximum tongue speed displayed a direct relationship with intelligibility.

DISCUSSION

Aging affects the phonatory and articulatory subsystems with implications for speech intelligibility. Phonatory cepstral/spectral measures (except mean CPP) were associated with speech intelligibility changes, suggesting that changes in voice quality may contribute to reduced intelligibility in older adults. Pertaining to articulation, slower tongue movement speed likely contributed to reduced intelligibility in older individuals.

The Spanish 12-item version of the Speech, Spatial and Qualities of Hearing scale (Sp-SSQ12): adaptation, reliability, and discriminant validity for people with and without hearing loss

PURPOSE

Because of the limited number of Spanish validated questionnaires available to assess auditory functionality in daily life situations in adults, the purpose of this study was to investigate the validity and the reliability of the Spanish version of the Speech, Spatial and Qualities of Hearing 12 items scale (sp-SSQ12), adapted from the published Spanish SSQ49, and to provide reference data for normal and hearing-impaired populations.

METHODS

The SSQ12 is a self-report questionnaire, consisting of 12 items assessing a range of daily life listening situations. One hundred fifty adults (101 female) with a mean age of 53.9 years (SD 20.3; range 20-88 years) took part in the study. Internal consistency, test-retest reliability, validity, and floor and ceiling effects were investigated.

RESULTS

The sp-SSQ12 questionnaire had high internal consistency (Cronbach's alpha = 0.95) and test-retest scores were highly correlated (ICC = 0.79). There was minimal evidence of floor and ceiling effects in our sample. Significant differences were observed overall and for the three subscales between normal and hearing-impaired groups. Although some significant differences in SSQ12 scores between groups of participants from different countries, these differences were minimal.

CONCLUSIONS

The sp-SSQ12 questionnaire is a valid and reliable tool that is easy to administer and requires a short time to answer. We recommend the use of this tool for the assessment of functional hearing in the Spanish-speaking population.Implication for rehabilitationHearing loss impacts people's lives in a number of ways that are captured in the SSQ.The sp-SSQ12 is a valid and reliable tool for assessing everyday listening abilities and limitations experienced by Spanish-speaking adults with hearing loss.The sp-SSQ12 can be incorporated in the hearing rehabilitation process as a tool for evaluating and improving hearing assessment and rehabilitation programs.The sp-SSQ12 can help to identify adults who require a comprehensive hearing assessment.

The Effect of Talker and Listener Depressive Symptoms on Speech Intelligibility

Purpose This study examined the effect of depressive symptoms on production and perception of conversational and clear speech (CS) sentences. Method Five talkers each with high-depressive (HD) and low-depressive (LD) symptoms read sentences in conversational and clear speaking style. Acoustic measures of speaking rate, mean fundamental frequency (F0; Hz), F0 range (Hz), and energy in the 1-3 kHz range (dB) were obtained. Thirty-two young adult participants (15 HD, 16 LD) heard these conversational and clear sentences mixed with energetic masking (speech-shaped noise) at -5 dB SPL signal-to-noise ratio. Another group of 39 young adult participants (18 HD, 19 LD) heard the same sentences mixed with informational masking (one-talker competing speech) at -12 dB SPL signal-to-noise ratio. The key word correct score was obtained. Results CS was characterized by a decreased speaking rate, increased F0 mean and range, and increased energy in the 1-3 kHz range. Talkers with HD symptoms produced these modifications significantly less compared to talkers with LD symptoms. When listening to speech in energetic masking (speech-shaped noise), listeners with both HD and LD symptoms benefited less from the CS produced by HD talkers. Listeners with HD symptoms performed significantly worse than listeners with LD symptoms when listening to speech in informational masking (one-talker competing speech). Conclusions Results provide evidence that depressive symptoms impact intelligibility and have the potential to aid in clinical decision making for individuals with depression.

Listening effort: Are we measuring cognition or affect, or both?

Listening effort is increasingly recognized as a factor in communication, particularly for and with nonnative speakers, for the elderly, for individuals with hearing impairment and/or for those working in noise. However, as highlighted by McGarrigle et al., International Journal of Audiology, 2014, 53, 433-445, the term "listening effort" encompasses a wide variety of concepts, including the engagement and control of multiple possibly distinct neural systems for information processing, and the affective response to the expenditure of those resources in a given context. Thus, experimental or clinical methods intended to objectively quantify listening effort may ultimately reflect a complex interaction between the operations of one or more of those information processing systems, and/or the affective and motivational response to the demand on those systems. Here we examine theoretical, behavioral, and psychophysiological factors related to resolving the question of what we are measuring, and why, when we measure "listening effort." This article is categorized under: Linguistics > Language in Mind and Brain Psychology > Theory and Methods Psychology > Attention Psychology > Emotion and Motivation.

Effect of Auditory Task Type on Physiological and Subjective Measures of Listening Effort in Individuals With Normal Hearing

Purpose Listening effort has traditionally been measured using subjective rating scales and behavioral measures. Recent physiological measures of listening effort have utilized pupil dilation. Using a combination of physiological and subjective measures of listening effort, this study aimed to identify differences in listening effort during 2 auditory tasks: sentence recognition and word recognition. Method Pupil dilation and subjective ratings of listening effort were obtained for auditory tasks utilizing AzBio sentences recognition and Northwestern University Auditory Test No. 6 words recognition, across 3 listening situations: in quiet, at +6 dB signal-to-noise ratio, and at 0 dB signal-to-noise ratio. Task accuracy was recorded for each of the 6 conditions, as well as peak pupil dilation and a subjective rating of listening effort. Results A significant impact of listening situation (quiet vs. noise) and task type (sentence recognition vs. word recognition) on both physiological and subjective measures was found. There was a significant interaction between listening situation and task type, suggesting that contextual cues may only be beneficial when audibility is uncompromised. The current study found no correlation between the physiological and subjective measures, possibly suggesting that these measures analyze different aspects of cognitive effort in a listening task.

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.

Perceived listener effort as an outcome measure for disordered speech

PURPOSE

Perceived listening effort is a perceptual dimension used to identify the amount of work necessary to understand disordered speech. The purpose of this study was to investigate the utility of perceived listening effort to provide unique information about disordered speech. The relationships between perceived listening effort and two current outcome measures (speech acceptability, intelligibility) were examined for listeners rating electrolaryngeal speech, along with their reliability and intra-rater agreement.

METHODS

Ten healthy male speakers read low-context sentences using an electrolarynx. Twenty-five inexperienced listeners orthographically transcribed and rated the stimuli for perceived listening effort and speech acceptability using a visual analog scale. Strict reliability and agreement criteria were set.

RESULTS

Perceived listening effort was moderately to strongly correlated with intelligibility (r = -0.76) and acceptability (r = -0.80), each of which contributed uniquely to ratings of perceived listening effort. However, only 17 listeners met stringent reliability and agreement criteria.

CONCLUSIONS

Ratings of perceived listening effort may provide unique information about the communicative success of individuals with communication disorders. There is great variability, however, among inexperienced listeners' perceptual ratings of electrolaryngeal speech. Future research should investigate variables that may affect perceived listening effort specifically and auditory-perceptual ratings in general.

Effects of Familiarization on Intelligibility of Dysarthric Speech in Older Adults With and Without Hearing Loss

PURPOSE

Familiarization tasks offer a promising platform for listener-targeted remediation of intelligibility disorders associated with dysarthria. To date, the body of work demonstrating improved understanding of dysarthric speech following a familiarization experience has been carried out on younger adults. The primary purpose of the present study was to examine the intelligibility effects of familiarization in older adults.

METHOD

Nineteen older adults, with and without hearing loss, completed a familiarization protocol consisting of three phases: pretest, familiarization, and posttest. The older adults' initial intelligibility and intelligibility improvement scores were compared with previously reported data collected from 50 younger adults (Borrie, Lansford, & Barrett, 2017a).

RESULTS

Relative to younger adults, initial intelligibility scores were significantly lower for older adults, although additional analysis revealed that the difference was limited to older adults with hearing loss. Key, however, is that irrespective of hearing status, the older and younger adults achieved comparable intelligibility improvement following familiarization (gain of roughly 20 percentage points).

CONCLUSION

This study extends previous findings of improved intelligibility of dysarthria following familiarization to a group of listeners who are critical to consider in listener-targeted remediation, namely, aging caregivers and/or spouses of individuals with dysarthria.

Acoustics of Clear and Noise-Adapted Speech in Children, Young, and Older Adults

PURPOSE

This study investigated acoustic-phonetic modifications produced in noise-adapted speech (NAS) and clear speech (CS) by children, young adults, and older adults.

METHOD

Ten children (11-13 years of age), 10 young adults (18-29 years of age), and 10 older adults (60-84 years of age) read sentences in conversational and clear speaking style in quiet and in noise. A number of acoustic measurements were obtained.

RESULTS

NAS and CS were characterized by a decrease in speaking rate and an increase in 1-3 kHz energy, sound pressure level (SPL), vowel space area (VSA), and harmonics-to-noise ratio. NAS increased fundamental frequency (F0) mean and decreased jitter and shimmer. CS increased frequency and duration of pauses. Older adults produced the slowest speaking rate, longest pauses, and smallest increase in F0 mean, 1-3 kHz energy, and SPL when speaking clearly. They produced the smallest increases in VSA in NAS and CS. Children slowed down less, increased the VSA least, increased harmonics-to-noise ratio, and decreased jitter and shimmer most in CS. Children increased mean F0 and F1 most in noise.

CONCLUSIONS

Findings have implications for a model of speech production in healthy speakers as well as the potential to aid in clinical decision making for individuals with speech disorders, particularly dysarthria.

Intelligibility of Noise-Adapted and Clear Speech in Child, Young Adult, and Older Adult Talkers

PURPOSE

This study examined intelligibility of conversational and clear speech sentences produced in quiet and in noise by children, young adults, and older adults. Relative talker intelligibility was assessed across speaking styles.

METHOD

Sixty-one young adult participants listened to sentences mixed with speech-shaped noise at -5 dB signal-to-noise ratio. The analyses examined percent correct scores across conversational, clear, and noise-adapted conditions and the three talker groups. Correlation analyses examined whether talker intelligibility is consistent across speaking style adaptations.

RESULTS

Noise-adapted and clear speech significantly enhanced intelligibility for young adult listeners. The intelligibility improvement varied across the three talker groups. Notably, intelligibility benefit was smallest for children's speaking style modifications. Listeners also perceived speech produced in noise by older adults to be less intelligible compared to the younger talkers. Talker intelligibility was correlated strongly between conversational and clear speech in quiet, but not for conversational speech produced in quiet and in noise.

CONCLUSIONS

Results provide evidence that intelligibility variation related to age and communicative barrier has the potential to aid clinical decision making for individuals with speech disorders, particularly dysarthria.

Comparison of Single-Task versus Dual-Task for Listening Effort

Background and Objectives

Depending on the kind of task and/or material, listeners sometimes need to pay attention to understand communication. The present study aimed to estimate a listener’s amount of effort needed to understand communication by using recognition score and response time as a function of signal-to-noise ratio (SNR) and to confirm his/ her task dependency for listening effort.

Subjects and Methods

Forty-eight young adults with normal hearing participated in the study. As stimuli, Korean Speech Perception in Noise test without a question tag and three consecutive digits were used for sentence recognition (or single-task) and arithmetic (or dual-task), respectively. Both tasks were measured in quiet and under four SNR (i.e., 0, -4, -8, -12 dB) conditions. Their outcomes were analyzed and compared in terms of percent correct and response time.

Results

Sentence recognition scores and arithmetic scores decreased as the level of noise increased. Response time for sentence recognition decreased as noise increased, whereas the response time for arithmetic increased as noise increased. In addition, there was a negative correlation between error percent and response time in the sentence recognition. Conversely, a positive correlation between error percent and response time appeared in the arithmetic test.

Conclusions

Listening effort showed a different pattern based on the kind of task, single vs. dual, while the dual-task required greater effort from the listener.

Impact of Background Noise and Sentence Complexity on Processing Demands during Sentence Comprehension

Speech comprehension in adverse listening conditions can be effortful even when speech is fully intelligible. Acoustical distortions typically make speech comprehension more effortful, but effort also depends on linguistic aspects of the speech signal, such as its syntactic complexity. In the present study, pupil dilations, and subjective effort ratings were recorded in 20 normal-hearing participants while performing a sentence comprehension task. The sentences were either syntactically simple (subject-first sentence structure) or complex (object-first sentence structure) and were presented in two levels of background noise both corresponding to high intelligibility. A digit span and a reading span test were used to assess individual differences in the participants' working memory capacity (WMC). The results showed that the subjectively rated effort was mostly affected by the noise level and less by syntactic complexity. Conversely, pupil dilations increased with syntactic complexity but only showed a small effect of the noise level. Participants with higher WMC showed increased pupil responses in the higher-level noise condition but rated sentence comprehension as being less effortful compared to participants with lower WMC. Overall, the results demonstrate that pupil dilations and subjectively rated effort represent different aspects of effort. Furthermore, the results indicate that effort can vary in situations with high speech intelligibility.

Cognitive-perceptual examination of remediation approaches to hypokinetic dysarthria

PURPOSE

To determine how increased vocal loudness and reduced speech rate affect listeners' cognitive-perceptual processing of hypokinetic dysarthric speech associated with Parkinson's disease.

METHOD

Fifty-one healthy listener participants completed a speech perception experiment. Listeners repeated phrases produced by 5 individuals with dysarthria across habitual, loud, and slow speaking modes. Listeners were allocated to habitual ( n = 17), loud ( n = 17), or slow ( n = 17) experimental conditions. Transcripts derived from the phrase repetition task were coded for overall accuracy (i.e., intelligibility), and perceptual error analyses examined how these conditions affected listeners' phonemic mapping (i.e., syllable resemblance) and lexical segmentation (i.e., lexical boundary error analysis).

RESULTS

Both speech conditions provided obvious perceptual benefits to listeners. Overall, transcript accuracy was highest in the slow condition. In the loud condition, however, improvement was evidenced across the experiment. An error analysis suggested that listeners in the loud condition prioritized acoustic-phonetic cues in their attempts to resolve the degraded signal, whereas those in the slow condition appeared to preferentially weight lexical stress cues.

CONCLUSIONS

Increased loudness and reduced rate exhibited differential effects on listeners' perceptual processing of dysarthric speech. The current study highlights the insights that may be gained from a cognitive-perceptual approach.

Vocabulary influences older and younger listeners' processing of dysarthric speech

This study examined younger (n = 16) and older (n = 16) listeners' processing of dysarthric speech-a naturally occurring form of signal degradation. It aimed to determine how age, hearing acuity, memory, and vocabulary knowledge interacted in speech recognition and lexical segmentation. Listener transcripts were coded for accuracy and pattern of lexical boundary errors. For younger listeners, transcription accuracy was predicted by receptive vocabulary. For older listeners, this same effect existed but was moderated by pure-tone hearing thresholds. While both groups employed syllabic stress cues to inform lexical segmentation, older listeners were less reliant on this perceptual strategy. The results were interpreted to suggest that individuals with larger receptive vocabularies, with their presumed greater language familiarity, were better able to leverage cue redundancies within the speech signal to form lexical hypothesis-leading to an improved ability to comprehend dysarthric speech. This advantage was minimized as hearing thresholds increased. While the differing levels of reliance on stress cues across the listener groups could not be attributed to specific individual differences, it was hypothesized that some combination of larger vocabularies and reduced hearing thresholds in the older participant group led to them prioritize lexical cues as a segmentation frame.