On The (Un)importance of Working Memory in Speech-in-Noise Processing for Listeners with Normal Hearing Thresholds

The contribution of short-term memory for sound features to speech-in-noise perception and cognition

Speech-in-noise (SIN) perception is a fundamental ability that declines with aging, as does general cognition. We assess whether auditory cognitive ability, in particular short-term memory for sound features, contributes to both. We examined how auditory memory for fundamental sound features, the carrier frequency and amplitude modulation rate of modulated white noise, contributes to SIN perception. We assessed SIN in 153 healthy participants with varying degrees of hearing loss using measures that require single-digit perception (the Digits-in-Noise, DIN) and sentence perception (Speech-in-Babble, SIB). Independent variables were auditory memory and a range of other factors including the Pure Tone Audiogram (PTA), a measure of dichotic pitch-in-noise perception (Huggins pitch), and demographic variables including age and sex. Multiple linear regression models were compared using Bayesian Model Comparison. The best predictor model for DIN included PTA and Huggins pitch (r2 = 0.32, p < 0.001), whereas the model for SIB included the addition of auditory memory for sound features (r2 = 0.24, p < 0.001). Further analysis demonstrated that auditory memory also explained a significant portion of the variance (28 %) in scores for a screening cognitive test for dementia. Auditory memory for non-speech sounds may therefore provide an important predictor of both SIN and cognitive ability.

A Scoping Review and Meta-Analysis of the Relations Between Cognition and Cochlear Implant Outcomes and the Effect of Quiet Versus Noise Testing Conditions

OBJECTIVES

Evidence continues to emerge of associations between cochlear implant (CI) outcomes and cognitive functions in postlingually deafened adults. While there are multiple factors that appear to affect these associations, the impact of speech recognition background testing conditions (i.e., in quiet versus noise) has not been systematically explored. The two aims of this study were to (1) identify associations between speech recognition following cochlear implantation and performance on cognitive tasks, and to (2) investigate the impact of speech testing in quiet versus noise on these associations. Ultimately, we want to understand the conditions that impact this complex relationship between CI outcomes and cognition.

DESIGN

A scoping review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed on published literature evaluating the relation between outcomes of cochlear implantation and cognition. The current review evaluates 39 papers that reported associations between over 30 cognitive assessments and speech recognition tests in adult patients with CIs. Six cognitive domains were evaluated: Global Cognition, Inhibition-Concentration, Memory and Learning, Controlled Fluency, Verbal Fluency, and Visuospatial Organization. Meta-analysis was conducted on three cognitive assessments among 12 studies to evaluate relations with speech recognition outcomes. Subgroup analyses were performed to identify whether speech recognition testing in quiet versus in background noise impacted its association with cognitive performance.

RESULTS

Significant associations between cognition and speech recognition in a background of quiet or noise were found in 69% of studies. Tests of Global Cognition and Inhibition-Concentration skills resulted in the highest overall frequency of significant associations with speech recognition (45% and 57%, respectively). Despite the modest proportion of significant associations reported, pooling effect sizes across samples through meta-analysis revealed a moderate positive correlation between tests of Global Cognition (r = +0.37, p < 0.01) as well as Verbal Fluency (r = +0.44, p < 0.01) and postoperative speech recognition skills. Tests of Memory and Learning are most frequently utilized in the setting of CI (in 26 of 39 included studies), yet meta-analysis revealed nonsignificant associations with speech recognition performance in a background of quiet (r = +0.30, p = 0.18), and noise (r = -0.06, p = 0.78).

CONCLUSIONS

Background conditions of speech recognition testing may influence the relation between speech recognition outcomes and cognition. The magnitude of this effect of testing conditions on this relationship appears to vary depending on the cognitive construct being assessed. Overall, Global Cognition and Inhibition-Concentration skills are potentially useful in explaining speech recognition skills following cochlear implantation. Future work should continue to evaluate these relations to appropriately unify cognitive testing opportunities in the setting of cochlear implantation.

Audiovisual perception of interrupted speech by nonnative listeners

The purpose of the present study was to examine the influence of visual cues in audiovisual perception of interrupted speech by nonnative English listeners and to identify the role of working memory, long-term memory retrieval, and vocabulary knowledge in audiovisual perception by nonnative listeners. The participants included 31 Mandarin-speaking English learners between 19 and 41 years of age. The perceptual stimuli were noise-filled periodically interrupted AzBio and QuickSIN sentences with or without visual cues that showed a male speaker uttering the sentences. In addition to sentence recognition, the listeners completed a semantic fluency task, verbal (operation span) and visuospatial (symmetry span) working memory tasks, and two vocabulary knowledge tests (Vocabulary Level Test and Lexical Test for Advanced Learners of English). The results revealed significantly better speech recognition in the audio-visual condition than the audio-only condition, but the magnitude of visual benefit was substantially attenuated for sentences that had limited semantic context. The listeners' vocabulary size in English played a key role in the restoration of missing speech information and audiovisual integration in the perception of interrupted speech. Meanwhile, the listeners' verbal working memory capacity played an important role in audiovisual integration especially for the difficult stimuli with limited semantic context.

Elderly people with hearing loss and cognitive decline: speech perception performance in noise

PURPOSE

To verify the influence of verbal intellectual-cognitive skills on speech perception in noise, in elderly with sensorineural hearing loss, considering education, age, and degree of hearing loss.

METHODS

36 elderly between 60 and 89 years old with bilateral sensorineural hearing loss participated in the study. After psychological assessment using the Wechsler Intelligence Scale for Adults (WAIS-III), they were grouped into (GI) 24 elderly without cognitive alteration and (GII) 12 elderly with risk of cognitive alteration. They underwent otorhinolaryngological assessment, audiological interview, pure tone audiometry, and assessment of speech perception in noise using the Hearing in Noise Test (HINT-Brazil). The Mann-Whitney U statistical test compared the results between the groups, and the Spearman correlation verified the variable's age, degree of hearing loss, and level of education.

RESULTS

There was no difference between the groups in the ability to perceive speech in noise, except in the noise on the left condition, in which GII showed better performance in HINT-Brazil. The degree of hearing loss and level of education influenced the perception of speech in noise. The level of education was correlated with the WAIS-III results.

CONCLUSION

The decline in verbal intellectual-cognitive skills did not affect speech perception of noise in the elderly with hearing loss. The degree of hearing loss and level of education influenced the performance of the elderly in the speech perception test in noise. Performance in verbal cognitive skills varied according to the level of education.

Developmental Effects in the "Vocale Rapide dans le Bruit" Speech-in-Noise Identification Test: Reference Performances of Normal-Hearing Children and Adolescents

PURPOSE

The main objective of this study was to assess the existence of developmental effects on the performance of the Vocale Rapide dans le Bruit (VRB) speech-in-noise (SIN) identification test that was recently developed for the French language and to collect reference scores for children and adolescents.

METHOD

Seventy-two native French speakers, aged 10-20 years, participated in the study. Each participant listened and repeated four lists of eight sentences, each containing three key words to be scored. The sentences were presented in free field at different signal-to-noise ratios (SNRs) using a four-talker babble noise. The SNR yielding 50% of correct repetitions of key words (SNR50) was recorded for each list.

RESULTS

A strong relationship between age and SNR50 was found, better performance occurring with increasing age (average drop in SNR50 per year: 0.34 dB). Large differences (Cohen's d ≥ 1.2) were observed between the SNR50 achieved by 10- to 13-year-old participants and those of adults. For participants aged 14-15 years, the difference fell just above the 5% level of significance. No effects of hearing thresholds or level of education were observed.

CONCLUSIONS

The study confirms the existence of developmental effects on SIN identification performance as measured using the VRB test and provides reference data for taking into account these effects during clinical practice. Explanations as to why age effects perdure during adolescence are discussed.

Midlife Speech Perception Deficits: Impact of Extended High-Frequency Hearing, Peripheral Neural Function, and Cognitive Abilities

OBJECTIVES

The objectives of the present study were to investigate the effects of age-related changes in extended high-frequency (EHF) hearing, peripheral neural function, working memory, and executive function on speech perception deficits in middle-aged individuals with clinically normal hearing.

DESIGN

We administered a comprehensive assessment battery to 37 participants spanning the age range of 20 to 56 years. This battery encompassed various evaluations, including standard and EHF pure-tone audiometry, ranging from 0.25 to 16 kHz. In addition, we conducted auditory brainstem response assessments with varying stimulation rates and levels, a spatial release from masking (SRM) task, and cognitive evaluations that involved the Trail Making test (TMT) for assessing executive function and the Abbreviated Reading Span test (ARST) for measuring working memory.

RESULTS

The results indicated a decline in hearing sensitivities at EHFs and an increase in completion times for the TMT with age. In addition, as age increased, there was a corresponding decrease in the amount of SRM. The declines in SRM were associated with age-related declines in hearing sensitivity at EHFs and TMT performance. While we observed an age-related decline in wave I responses, this decline was primarily driven by age-related reductions in EHF thresholds. In addition, the results obtained using the ARST did not show an age-related decline. Neither the auditory brainstem response results nor ARST scores were correlated with the amount of SRM.

CONCLUSIONS

These findings suggest that speech perception deficits in middle age are primarily linked to declines in EHF hearing and executive function, rather than cochlear synaptopathy or working memory.

Identifying Links Between Latent Memory and Speech Recognition Factors

OBJECTIVES

The link between memory ability and speech recognition accuracy is often examined by correlating summary measures of performance across various tasks, but interpretation of such correlations critically depends on assumptions about how these measures map onto underlying factors of interest. The present work presents an alternative approach, wherein latent factor models are fit to trial-level data from multiple tasks to directly test hypotheses about the underlying structure of memory and the extent to which latent memory factors are associated with individual differences in speech recognition accuracy. Latent factor models with different numbers of factors were fit to the data and compared to one another to select the structures which best explained vocoded sentence recognition in a two-talker masker across a range of target-to-masker ratios, performance on three memory tasks, and the link between sentence recognition and memory.

DESIGN

Young adults with normal hearing (N = 52 for the memory tasks, of which 21 participants also completed the sentence recognition task) completed three memory tasks and one sentence recognition task: reading span, auditory digit span, visual free recall of words, and recognition of 16-channel vocoded Perceptually Robust English Sentence Test Open-set sentences in the presence of a two-talker masker at target-to-masker ratios between +10 and 0 dB. Correlations between summary measures of memory task performance and sentence recognition accuracy were calculated for comparison to prior work, and latent factor models were fit to trial-level data and compared against one another to identify the number of latent factors which best explains the data. Models with one or two latent factors were fit to the sentence recognition data and models with one, two, or three latent factors were fit to the memory task data. Based on findings with these models, full models that linked one speech factor to one, two, or three memory factors were fit to the full data set. Models were compared via Expected Log pointwise Predictive Density and post hoc inspection of model parameters.

RESULTS

Summary measures were positively correlated across memory tasks and sentence recognition. Latent factor models revealed that sentence recognition accuracy was best explained by a single factor that varied across participants. Memory task performance was best explained by two latent factors, of which one was generally associated with performance on all three tasks and the other was specific to digit span recall accuracy at lists of six digits or more. When these models were combined, the general memory factor was closely related to the sentence recognition factor, whereas the factor specific to digit span had no apparent association with sentence recognition.

CONCLUSIONS

Comparison of latent factor models enables testing hypotheses about the underlying structure linking cognition and speech recognition. This approach showed that multiple memory tasks assess a common latent factor that is related to individual differences in sentence recognition, although performance on some tasks was associated with multiple factors. Thus, while these tasks provide some convergent assessment of common latent factors, caution is needed when interpreting what they tell us about speech recognition.

Development of the mandarin reading span test and confirmation of its relationship with speech perception in noise

OBJECTIVE

This study aimed to develop a dual-task Mandarin Reading Span Test (RST) to assess verbal working memory related to speech perception in noise.

DESIGN

The test material was developed taking into account psycholinguistic factors (i.e. sentence structure, number of syllables, word familiarity, and sentences plausibility), to achieve good test reliability and face validity. The relationship between the 28-sentence Mandarin RST and speech perception in noise was confirmed using three speech perception in noise measures containing varying levels of contextual and linguistic information.

STUDY SAMPLE

The study comprised 42 young adults with normal hearing and 56 older adult who were hearing aid users with moderate to severe hearing loss.

RESULTS

In older hearing aid users, the 28-sentence RST showed significant correlation with speech reception thresholds as measured by three Mandarin sentence in noise tests (rs or r = -.681 to -.419) but not with the 2-digit sequence Digit-in-Noise Test.

CONCLUSION

The newly developed dual-task Mandarin RST, constructed with careful psycholinguistic consideration, demonstrates a significant relationship with sentence perception in noise. This suggests that the Mandarin RST could serve as a measure of verbal working memory.

Relationships Between Auditory Processing and Cognitive Abilities in Adults: A Systematic Review

PURPOSE

The contributions from the central auditory and cognitive systems play a major role in communication. Understanding the relationship between auditory and cognitive abilities has implications for auditory rehabilitation for clinical patients. The purpose of this systematic review is to address the question, "In adults, what is the relationship between central auditory processing abilities and cognitive abilities?"

METHOD

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to identify, screen, and determine eligibility for articles that addressed the research question of interest. Medical librarians and subject matter experts assisted in search strategy, keyword review, and structuring the systematic review process. To be included, articles needed to have an auditory measure (either behavioral or electrophysiologic), a cognitive measure that assessed individual ability, and the measures needed to be compared to one another.

RESULTS

Following two rounds of identification and screening, 126 articles were included for full analysis. Central auditory processing (CAP) measures were grouped into categories (behavioral: speech in noise, altered speech, temporal processing, binaural processing; electrophysiologic: mismatch negativity, P50, N200, P200, and P300). The most common CAP measures were sentence recognition in speech-shaped noise and the P300. Cognitive abilities were grouped into constructs, and the most common construct was working memory. The findings were mixed, encompassing both significant and nonsignificant relationships; therefore, the results do not conclusively establish a direct link between CAP and cognitive abilities. Nonetheless, several consistent relationships emerged across different domains. Distorted or noisy speech was related to working memory or processing speed. Auditory temporal order tasks showed significant relationships with working memory, fluid intelligence, or multidomain cognitive measures. For electrophysiology, relationships were observed between some cortical evoked potentials and working memory or executive/inhibitory processes. Significant results were consistent with the hypothesis that assessments of CAP and cognitive processing would be positively correlated.

CONCLUSIONS

Results from this systematic review summarize relationships between CAP and cognitive processing, but also underscore the complexity of these constructs, the importance of study design, and the need to select an appropriate measure. The relationship between auditory and cognitive abilities is complex but can provide informative context when creating clinical management plans. This review supports a need to develop guidelines and training for audiologists who wish to consider individual central auditory and cognitive abilities in patient care.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24855174.

Is Recognition of Speech in Noise Related to Memory Disruption Caused by Irrelevant Sound?

Listeners with normal audiometric thresholds show substantial variability in their ability to understand speech in noise (SiN). These individual differences have been reported to be associated with a range of auditory and cognitive abilities. The present study addresses the association between SiN processing and the individual susceptibility of short-term memory to auditory distraction (i.e., the irrelevant sound effect [ISE]). In a sample of 67 young adult participants with normal audiometric thresholds, we measured speech recognition performance in a spatial listening task with two interfering talkers (speech-in-speech identification), audiometric thresholds, binaural sensitivity to the temporal fine structure (interaural phase differences [IPD]), serial memory with and without interfering talkers, and self-reported noise sensitivity. Speech-in-speech processing was not significantly associated with the ISE. The most important predictors of high speech-in-speech recognition performance were a large short-term memory span, low IPD thresholds, bilaterally symmetrical audiometric thresholds, and low individual noise sensitivity. Surprisingly, the susceptibility of short-term memory to irrelevant sound accounted for a substantially smaller amount of variance in speech-in-speech processing than the nondisrupted short-term memory capacity. The data confirm the role of binaural sensitivity to the temporal fine structure, although its association to SiN recognition was weaker than in some previous studies. The inverse association between self-reported noise sensitivity and SiN processing deserves further investigation.

A Step Toward Precision Audiology: Individual Differences and Characteristic Profiles From Auditory Perceptual and Cognitive Abilities

Older adults with normal hearing or with age-related hearing loss face challenges when listening to speech in noisy environments. To better serve individuals with communication difficulties, precision diagnostics are needed to characterize individuals' auditory perceptual and cognitive abilities beyond pure tone thresholds. These abilities can be heterogenous across individuals within the same population. The goal of the present study is to consider the suprathreshold variability and develop characteristic profiles for older adults with normal hearing (ONH) and with hearing loss (OHL). Auditory perceptual and cognitive abilities were tested on ONH (n = 20) and OHL (n = 20) on an abbreviated test battery using portable automated rapid testing. Using cluster analyses, three main profiles were revealed for each group, showing differences in auditory perceptual and cognitive abilities despite similar audiometric thresholds. Analysis of variance showed that ONH profiles differed in spatial release from masking, speech-in-babble testing, cognition, tone-in-noise, and binaural temporal processing abilities. The OHL profiles differed in spatial release from masking, speech-in-babble testing, cognition, and tolerance to background noise performance. Correlation analyses showed significant relationships between auditory and cognitive abilities in both groups. This study showed that auditory perceptual and cognitive deficits can be present to varying degrees in the presence of audiometrically normal hearing and among listeners with similar degrees of hearing loss. The results of this study inform the need for taking individual differences into consideration and developing targeted intervention options beyond pure tone thresholds and speech testing.

Testing the Informativeness of Diverse Measures of Auditory Processing for Clinical Audiological Practice in Middle-Aged Adults in Mexico

PURPOSE

Standard clinical audiologic assessment is limited in its ability to capture variance in self-reported hearing difficulty. Additionally, the costs associated with clinical testing in audiology create financial barriers for hearing health care in developing countries like Mexico. This study used an open-source Spanish-language tool called PART (Portable Automated Rapid Testing) to test the hypothesis that a battery of assessments of auditory processing can complement standard clinical audiological assessment to better capture the variance of self-reported hearing difficulty.

METHOD

Forty-three adults between 40 and 69 years of age were tested in Mexico City using a traditional clinical pure-tone audiogram, cognitive screening, and a battery of PART-based auditory processing assessments including a speech-on-speech competition spatial release from masking task. Results were compared to self-reported hearing difficulty, assessed with a Spanish-language adaptation of the Hearing Handicap Inventory for the Elderly-Screening Version (HHIE-S).

RESULTS

Several measures from the PART battery exhibited stronger correlations with self-reported hearing difficulties than the pure-tone audiogram. The spatial release from masking task best captured variance in HHIE-S scores and remained significant after controlling for the effects of age, audibility, and cognitive score.

CONCLUSIONS

The spatial release from masking task can complement traditional clinical measures to better account for patient's self-reported hearing difficulty. Open-source access to this test in PART supports its implementation for Spanish speakers in clinical settings around the world at low cost.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24470140.

Sentence recognition with modulation-filtered speech segments for younger and older adults: Effects of hearing impairment and cognition

This study investigated word recognition for sentences temporally filtered within and across acoustic-phonetic segments providing primarily vocalic or consonantal cues. Amplitude modulation was filtered at syllabic (0-8 Hz) or slow phonemic (8-16 Hz) rates. Sentence-level modulation properties were also varied by amplifying or attenuating segments. Participants were older adults with normal or impaired hearing. Older adult speech recognition was compared to groups of younger normal-hearing adults who heard speech unmodified or spectrally shaped with and without threshold matching noise that matched audibility to hearing-impaired thresholds. Participants also completed cognitive and speech recognition measures. Overall, results confirm the primary contribution of syllabic speech modulations to recognition and demonstrate the importance of these modulations across vowel and consonant segments. Group differences demonstrated a hearing loss-related impairment in processing modulation-filtered speech, particularly at 8-16 Hz. This impairment could not be fully explained by age or poorer audibility. Principal components analysis identified a single factor score that summarized speech recognition across modulation-filtered conditions; analysis of individual differences explained 81% of the variance in this summary factor among the older adults with hearing loss. These results suggest that a combination of cognitive abilities and speech glimpsing abilities contribute to speech recognition in this group.

The role of working memory in speech recognition by hearing-impaired older listeners: does the task matter?

OBJECTIVE

Working memory refers to a cognitive system that holds a limited amount of information in a temporarily heightened state of availability, for use in ongoing cognitive tasks. Research suggests a link between working memory and speech recognition. In this study, we investigated this relationship using two working memory tests that differed in regard to the operationalisation of the link between working memory and attention: the auditory visual divided attention test (AVDAT) and the widely used reading span test.

DESIGN

The relationship between speech-in-noise recognition and working memory was examined for two different working memory tests that varied in methodological and theoretical aspects, using a within-subject design.

STUDY SAMPLE

Nineteen hearing-impaired older listeners participated.

RESULTS

We found a strong link between the reading span test and speech-in-noise recognition and a less robust link between the AVDAT and speech-in-noise recognition. There was evidence for the role of selective attention in speech-in-noise recognition, shown via the new AVDAT measure.

CONCLUSION

Our findings suggest that the strength of the relationship between speech-in-noise recognition and working memory may be influenced by the match between the demands and the stimuli of the speech-in-noise task and those of the working memory test.

Development of Mandarin Lexical Tone Identification in Noise and Its Relation With Working Memory

PURPOSE

This study aimed to examine the developmental trajectory of Mandarin tone identification in quiet and two noisy conditions: speech-shaped noise (SSN) and multitalker babble noise. In addition, we evaluated the relationship between tonal identification development and working memory capacity.

METHOD

Ninety-three typically developing children aged 5-8 years and 23 young adults completed categorical identification of two tonal continua (Tone 1-4 and Tone 2-3) in quiet, SSN, and babble noise. Their working memory was additionally measured using auditory digit span tests. Correlation analyses between digit span scores and boundary widths were performed.

RESULTS

Six-year-old children have achieved the adultlike ability of categorical identification of Tone 1-4 continuum under both types of noise. Moreover, 6-year-old children could identify Tone 2-3 continuum as well as adults in SSN. Nonetheless, the child participants, even 8-year-olds, performed worse when tokens from Tone 2-3 continuum were masked by babble noise. Greater working memory capacity was associated with better tone identification in noise for preschoolers aged 5-6 years; however, for school-age children aged 7-8 years, such correlation only existed in Tone 2-3 continuum in SSN.

CONCLUSIONS

Lexical tone perception might take a prolonged time to achieve adultlike competence in babble noise relative to SSN. Moreover, a significant interaction between masking type and stimulus difficulty was found, as indicated by Tone 2-3 being more susceptible to interference from babble noise than Tone 1-4. Furthermore, correlations between working memory capacity and tone perception in noise varied with developmental stage, stimulus difficulty, and masking type.

Development of Achieving Constancy in Lexical Tone Identification With Contextual Cues

PURPOSE

The aim of this study was to explore when and how Mandarin-speaking children use contextual cues to normalize speech variability in perceiving lexical tones. Two different cognitive mechanisms underlying speech normalization (lower level acoustic normalization and higher level acoustic-phonemic normalization) were investigated through the lexical tone identification task in nonspeech contexts and speech contexts, respectively. Besides, another aim of this study was to reveal how domain-general cognitive abilities contribute to the development of the speech normalization process.

METHOD

In this study, 94 five- to eight-year-old Mandarin-speaking children (50 boys, 44 girls) and 24 young adults (14 men, 10 women) were asked to identify ambiguous Mandarin high-level and mid-rising tones in either speech or nonspeech contexts. Furthermore, in this study, we tested participants' pitch sensitivity through a nonlinguistic pitch discrimination task and their working memory using the digit span task.

RESULTS

Higher level acoustic-phonemic normalization of lexical tones emerged at the age of 6 years and was relatively stable thereafter. However, lower level acoustic normalization was less stable across different ages. Neither pitch sensitivity nor working memory affected children's lexical tone normalization.

CONCLUSIONS

Mandarin-speaking children above 6 years of age successfully achieved constancy in lexical tone normalization based on speech contextual cues. The perceptual normalization of lexical tones was not affected by pitch sensitivity and working memory capacity.

Plasticity After Hearing Rehabilitation in the Aging Brain

Age-related hearing loss, presbycusis, is an unavoidable sensory degradation, often associated with the progressive decline of cognitive and social functions, and dementia. It is generally considered a natural consequence of the inner-ear deterioration. However, presbycusis arguably conflates a wide array of peripheral and central impairments. Although hearing rehabilitation maintains the integrity and activity of auditory networks and can prevent or revert maladaptive plasticity, the extent of such neural plastic changes in the aging brain is poorly appreciated. By reanalyzing a large-scale dataset of more than 2200 cochlear implant users (CI) and assessing the improvement in speech perception from 6 to 24 months of use, we show that, although rehabilitation improves speech understanding on average, age at implantation only minimally affects speech scores at 6 months but has a pejorative effect at 24 months post implantation. Furthermore, older subjects (>67 years old) were significantly more likely to degrade their performances after 2 years of CI use than the younger patients for each year increase in age. Secondary analysis reveals three possible plasticity trajectories after auditory rehabilitation to account for these disparities: Awakening, reversal of deafness-specific changes; Counteracting, stabilization of additional cognitive impairments; or Decline, independent pejorative processes that hearing rehabilitation cannot prevent. The role of complementary behavioral interventions needs to be considered to potentiate the (re)activation of auditory brain networks.

Predicting speech-in-noise ability in normal and impaired hearing based on auditory cognitive measures

Problems with speech-in-noise (SiN) perception are extremely common in hearing loss. Clinical tests have generally been based on measurement of SiN. My group has developed an approach to SiN based on the auditory cognitive mechanisms that subserve this, that might be relevant to speakers of any language. I describe how well these predict SiN, the brain systems for them, and tests of auditory cognition based on them that might be used to characterise SiN deficits in the clinic.

The effect of modality onset asynchrony and processing time on the recognition of text-supplemented speech

This study examined the effect of modality onset asynchrony and response processing time for the recognition of text-supplemented speech. Speech and text were periodically interrupted by noise or black bars, respectively, to preserve 50% of the sentence and presented in unimodal and multimodal conditions. Sentence recognition and response errors were assessed for responses made simultaneous with the stimulus or after its presentation. Increased processing time allowed for the cognitive repair of initial response errors in working memory. Text-supplemented speech was best recognized with minimal temporal asynchrony. Overall, text supplementation facilitated the recognition of degraded speech when provided sufficient processing time.

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.

No Link Between Speech-in-Noise Perception and Auditory Sensory Memory - Evidence From a Large Cohort of Older and Younger Listeners

A growing literature is demonstrating a link between working memory (WM) and speech-in-noise (SiN) perception. However, the nature of this correlation and which components of WM might underlie it, are being debated. We investigated how SiN reception links with auditory sensory memory (aSM) - the low-level processes that support the short-term maintenance of temporally unfolding sounds. A large sample of old (N = 199, 60-79 yo) and young (N = 149, 20-35 yo) participants was recruited online and performed a coordinate response measure-based speech-in-babble task that taps listeners' ability to track a speech target in background noise. We used two tasks to investigate implicit and explicit aSM. Both were based on tone patterns overlapping in processing time scales with speech (presentation rate of tones 20 Hz; of patterns 2 Hz). We hypothesised that a link between SiN and aSM may be particularly apparent in older listeners due to age-related reduction in both SiN reception and aSM. We confirmed impaired SiN reception in the older cohort and demonstrated reduced aSM performance in those listeners. However, SiN and aSM did not share variability. Across the two age groups, SiN performance was predicted by a binaural processing test and age. The results suggest that previously observed links between WM and SiN may relate to the executive components and other cognitive demands of the used tasks. This finding helps to constrain the search for the perceptual and cognitive factors that explain individual variability in SiN performance.

A structural equation mediation model captures the predictions amongst the parameters of the ease of language understanding model

Objective

The aim of the present study was to assess the validity of the Ease of Language Understanding (ELU) model through a statistical assessment of the relationships among its main parameters: processing speed, phonology, working memory (WM), and dB Speech Noise Ratio (SNR) for a given Speech Recognition Threshold (SRT) in a sample of hearing aid users from the n200 database.

Methods

Hearing aid users were assessed on several hearing and cognitive tests. Latent Structural Equation Models (SEMs) were applied to investigate the relationship between the main parameters of the ELU model while controlling for age and PTA. Several competing models were assessed.

Results

Analyses indicated that a mediating SEM was the best fit for the data. The results showed that (i) phonology independently predicted speech recognition threshold in both easy and adverse listening conditions and (ii) WM was not predictive of dB SNR for a given SRT in the easier listening conditions (iii) processing speed was predictive of dB SNR for a given SRT mediated via WM in the more adverse conditions.

Conclusion

The results were in line with the predictions of the ELU model: (i) phonology contributed to dB SNR for a given SRT in all listening conditions, (ii) WM is only invoked when listening conditions are adverse, (iii) better WM capacity aids the understanding of what has been said in adverse listening conditions, and finally (iv) the results highlight the importance and optimization of processing speed in conditions when listening conditions are adverse and WM is activated.

Performance on stochastic figure-ground perception varies with individual differences in speech-in-noise recognition and working memory capacity

Speech recognition in noisy environments can be challenging and requires listeners to accurately segregate a target speaker from irrelevant background noise. Stochastic figure-ground (SFG) tasks in which temporally coherent inharmonic pure-tones must be identified from a background have been used to probe the non-linguistic auditory stream segregation processes important for speech-in-noise processing. However, little is known about the relationship between performance on SFG tasks and speech-in-noise tasks nor the individual differences that may modulate such relationships. In this study, 37 younger normal-hearing adults performed an SFG task with target figure chords consisting of four, six, eight, or ten temporally coherent tones amongst a background of randomly varying tones. Stimuli were designed to be spectrally and temporally flat. An increased number of temporally coherent tones resulted in higher accuracy and faster reaction times (RTs). For ten target tones, faster RTs were associated with better scores on the Quick Speech-in-Noise task. Individual differences in working memory capacity and self-reported musicianship further modulated these relationships. Overall, results demonstrate that the SFG task could serve as an assessment of auditory stream segregation accuracy and RT that is sensitive to individual differences in cognitive and auditory abilities, even among younger normal-hearing adults.

Informational Masking and Listening Effort in Speech Recognition in Noise: The Role of Working Memory Capacity and Inhibitory Control in Older Adults With and Without Hearing Impairment

PURPOSE

The study aimed to assess the relationship between (a) speech recognition in noise, mask type, working memory capacity (WMC), and inhibitory control and (b) self-rated listening effort, speech material, and mask type, in older adults with and without hearing impairment. It was of special interest to assess the relationship between WMC, inhibitory control, and speech recognition in noise when informational maskers masked target speech.

METHOD

A mixed design was used. A group (N = 24) of older (M_age = 69.7 years) individuals with hearing impairment and a group of age normal-hearing adults (M_age = 59.3 years, SD = 6.5) participated in the study. The participants were presented with auditory tests in a sound-attenuated room and with cognitive tests in a quiet office. The participants were asked to rate listening effort after being presented with energetic and informational background maskers in two different speech materials used in this study (i.e., Hearing In Noise Test and Hagerman test). Linear mixed-effects models were set up to assess the effect of the two different speech materials, energetic and informational maskers, hearing ability, WMC, inhibitory control, and self-rated listening effort.

RESULTS

Results showed that WMC and inhibitory control were of importance for speech recognition in noise, even when controlling for pure-tone average 4 hearing thresholds and age, when the maskers were informational. Concerning listening effort, on the other hand, the results suggest that hearing ability, but not cognitive abilities, is important for self-rated listening effort in speech recognition in noise.

CONCLUSIONS

Speech-in-noise recognition is more dependent on WMC for older adults in informational maskers than in energetic maskers. Hearing ability is a stronger predictor than cognition for self-rated listening effort.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21357648.

Predicting speech-in-speech recognition: Short-term audibility, talker sex, and listener factors

Speech-in-speech recognition can be challenging, and listeners vary considerably in their ability to accomplish this complex auditory-cognitive task. Variability in performance can be related to intrinsic listener factors as well as stimulus factors associated with energetic and informational masking. The current experiments characterized the effects of short-term audibility of the target, differences in target and masker talker sex, and intrinsic listener variables on sentence recognition in two-talker speech and speech-shaped noise. Participants were young adults with normal hearing. Each condition included the adaptive measurement of speech reception thresholds, followed by testing at a fixed signal-to-noise ratio (SNR). Short-term audibility for each keyword was quantified using a computational glimpsing model for target+masker mixtures. Scores on a psychophysical task of auditory stream segregation predicted speech recognition, with stronger effects for speech-in-speech than speech-in-noise. Both speech-in-speech and speech-in-noise recognition depended on the proportion of audible glimpses available in the target+masker mixture, even across stimuli presented at the same global SNR. Short-term audibility requirements varied systematically across stimuli, providing an estimate of the greater informational masking for speech-in-speech than speech-in-noise recognition and quantifying informational masking for matched and mismatched talker sex.

Is Cantonese lexical tone information important for sentence recognition accuracy in quiet and in noise?

In Chinese languages, tones are used to express the lexical meaning of words. It is therefore important to analyze the role of lexical tone in Chinese sentence recognition accuracy. There is a lack of research on the role of Cantonese lexical tones in sentence recognition accuracy. Therefore, this study examined the contribution of lexical tone information to Cantonese sentence recognition accuracy and its cognitive correlates in adults with normal hearing (NH). A text-to-speech synthesis engine was used to synthesize Cantonese daily-use sentences with each word carrying an original or a flat lexical tone, which were then presented to 97 participants in quiet, in speech-shaped noise (SSN), and in two-talker babble (TTB) noise conditions. Both target sentences and noises were presented at 65 dB binaurally via insert headphones. It was found that listeners with NH can almost perfectly recognize a daily-use Cantonese sentence with mismatched lexical tone information in quiet, while their sentence recognition decreases substantially in noise. The same finding was reported for Mandarin, which has a relatively simple tonal system, suggesting that the current results may be applicable to other tonal languages. In addition, working memory (WM) was significantly related to decline in sentence recognition score in the TTB but not in the SSN, when the lexical tones were mismatched. This finding can be explained using the Ease of Language Understanding model and suggests that those with higher WM are less likely to be affected by the degraded lexical information for perceiving daily-use sentences in the TTB.

Immediate Effects of (Simulated) Age-Related Hearing Loss on Cognitive Processing and Performance for the Backward-Digit-Span Task

The recall of auditorily presented sequences of digits in reverse order (also known as the Backward Digit Span, BDS) is considered to reflect a person's information storage and processing abilities which have been linked to speech-in-noise intelligibility. However, especially in aging research and audiology, persons who are administered the BDS task are often affected by hearing loss (HL). If uncorrected, HL can have immediate assessment-format-related effects on cognitive-test performance and can result, in the long term, in neuroplastic changes impacting cognitive functioning. In the present study, an impairment-simulation approach, mimicking mild-to-moderate age-related HLs typical for persons aged 65, 75, and 85 years, was used in 19 young normal-hearing participants to evaluate the impact of HL on cognitive performance and the cognitive processes probed by the BDS task. Participants completed the BDS task in several listening conditions, as well as several commonly used visual tests of short-term and working memory. The results indicated that BDS performance was impaired by a simulated HL representing that of persons aged 75 years and above. In the normal-hearing condition, BDS performance correlated positively with both performance on tests of short-term memory and performance on tests of working memory. In the listening condition simulating moderate HL (as experienced by the average 85-year-old person), BDS performance only correlated with performance on working-memory tests. In conclusion, simulated (and, by extrapolation, actual) age-related HL negatively affects cognitive-test performance and may change the composition of the cognitive processes associated with the completion of a cognitive task.

Is Having Hearing Loss Fundamentally Different? Multigroup Structural Equation Modeling of the Effect of Cognitive Functioning on Speech Identification

OBJECTIVES

Previous research suggests that there is a robust relationship between cognitive functioning and speech-in-noise performance for older adults with age-related hearing loss. For normal-hearing adults, on the other hand, the research is not entirely clear. Therefore, the current study aimed to examine the relationship between cognitive functioning, aging, and speech-in-noise, in a group of older normal-hearing persons and older persons with hearing loss who wear hearing aids.

DESIGN

We analyzed data from 199 older normal-hearing individuals (mean age = 61.2) and 200 older individuals with hearing loss (mean age = 60.9) using multigroup structural equation modeling. Four cognitively related tasks were used to create a cognitive functioning construct: the reading span task, a visuospatial working memory task, the semantic word-pairs task, and Raven's progressive matrices. Speech-in-noise, on the other hand, was measured using Hagerman sentences. The Hagerman sentences were presented via an experimental hearing aid to both normal hearing and hearing-impaired groups. Furthermore, the sentences were presented with one of the two background noise conditions: the Hagerman original speech-shaped noise or four-talker babble. Each noise condition was also presented with three different hearing processing settings: linear processing, fast compression, and noise reduction.

RESULTS

Cognitive functioning was significantly related to speech-in-noise identification. Moreover, aging had a significant effect on both speech-in-noise and cognitive functioning. With regression weights constrained to be equal for the two groups, the final model had the best fit to the data. Importantly, the results showed that the relationship between cognitive functioning and speech-in-noise was not different for the two groups. Furthermore, the same pattern was evident for aging: the effects of aging on cognitive functioning and aging on speech-in-noise were not different between groups.

CONCLUSION

Our findings revealed similar cognitive functioning and aging effects on speech-in-noise performance in older normal-hearing and aided hearing-impaired listeners. In conclusion, the findings support the Ease of Language Understanding model as cognitive processes play a critical role in speech-in-noise independent from the hearing status of elderly individuals.

The cognitive hearing science perspective on perceiving, understanding, and remembering language: The ELU model

The review gives an introductory description of the successive development of data patterns based on comparisons between hearing-impaired and normal hearing participants’ speech understanding skills, later prompting the formulation of the Ease of Language Understanding (ELU) model. The model builds on the interaction between an input buffer (RAMBPHO, Rapid Automatic Multimodal Binding of PHOnology) and three memory systems: working memory (WM), semantic long-term memory (SLTM), and episodic long-term memory (ELTM). RAMBPHO input may either match or mismatch multimodal SLTM representations. Given a match, lexical access is accomplished rapidly and implicitly within approximately 100–400 ms. Given a mismatch, the prediction is that WM is engaged explicitly to repair the meaning of the input – in interaction with SLTM and ELTM – taking seconds rather than milliseconds. The multimodal and multilevel nature of representations held in WM and LTM are at the center of the review, being integral parts of the prediction and postdiction components of language understanding. Finally, some hypotheses based on a selective use-disuse of memory systems mechanism are described in relation to mild cognitive impairment and dementia. Alternative speech perception and WM models are evaluated, and recent developments and generalisations, ELU model tests, and boundaries are discussed.

Reconsidering commonly used stimuli in speech perception experiments

This paper examines some commonly used stimuli in speech perception experiments and raises questions about their use, or about the interpretations of previous results. The takeaway messages are: 1) the Hillenbrand vowels represent a particular dialect rather than a gold standard, and English vowels contain spectral dynamics that have been largely underappreciated, 2) the /ɑ/ context is very common but not clearly superior as a context for testing consonant perception, 3) /ɑ/ is particularly problematic when testing voice-onset-time perception because it introduces strong confounds in the formant transitions, 4) /dɑ/ is grossly overrepresented in neurophysiological studies and yet is insufficient as a generalized proxy for "speech perception," and 5) digit tests and matrix sentences including the coordinate response measure are systematically insensitive to important patterns in speech perception. Each of these stimulus sets and concepts is described with careful attention to their unique value and also cases where they might be misunderstood or over-interpreted.

Transcranial Direct Current Stimulation Combined With Listening to Preferred Music Alters Cortical Speech Processing in Older Adults

Emerging evidence suggests transcranial direct current stimulation (tDCS) can improve cognitive performance in older adults. Similarly, music listening may improve arousal and stimulate subsequent performance on memory-related tasks. We examined the synergistic effects of tDCS paired with music listening on auditory neurobehavioral measures to investigate causal evidence of short-term plasticity in speech processing among older adults. In a randomized sham-controlled crossover study, we measured how combined anodal tDCS over dorsolateral prefrontal cortex (DLPFC) paired with listening to autobiographically salient music alters neural speech processing in older adults compared to either music listening (sham stimulation) or tDCS alone. EEG assays included both frequency-following responses (FFRs) and auditory event-related potentials (ERPs) to trace neuromodulation-related changes at brainstem and cortical levels. Relative to music without tDCS (sham), we found tDCS alone (without music) modulates the early cortical neural encoding of speech in the time frame of ∼100-150 ms. Whereas tDCS by itself appeared to largely produce suppressive effects (i.e., reducing ERP amplitude), concurrent music with tDCS restored responses to those of the music+sham levels. However, the interpretation of this effect is somewhat ambiguous as this neural modulation could be attributable to a true effect of tDCS or presence/absence music. Still, the combined benefit of tDCS+music (above tDCS alone) was correlated with listeners' education level suggesting the benefit of neurostimulation paired with music might depend on listener demographics. tDCS changes in speech-FFRs were not observed with DLPFC stimulation. Improvements in working memory pre to post session were also associated with better speech-in-noise listening skills. Our findings provide new causal evidence that combined tDCS+music relative to tDCS-alone (i) modulates the early (100-150 ms) cortical encoding of speech and (ii) improves working memory, a cognitive skill which may indirectly bolster noise-degraded speech perception in older listeners.

The Associations of Hearing Sensitivity and Different Cognitive Functions with Perception of Speech-in-Noise

OBJECTIVES

Impaired speech-in-noise perception affects individuals' daily lives and is a frequent symptom of age-related hearing loss, which is a common disabling condition and a health concern in aging populations. The relative impact of hearing sensitivity loss and different cognitive functions on speech-in-noise perception is not well understood. We aimed to assess to what extent hearing sensitivity and different cognitive functions were associated with sentence-in-noise performance across the adult lifespan.

DESIGN

This study is based on data of 2585 participants of the Rhineland Study, which is a German community-based cohort study of persons of age 30 years and older. We assessed speech-in-noise with a sentence-in-noise test (Göttinger Satztest), hearing sensitivity thresholds (air conduction pure-tone audiometry [PTA] average of 0.5, 1, 2, and 4 kHz), and the following cognitive domains: crystallized intelligence (German Mehrfachwahl-Wortschatz-Intelligenztest, MWT-B), executive functioning (Trail Making Test B, TMT), working memory (Digit Span forward, DS), and long-term memory (Verbal Learning and Memory Test delayed recall; VLMT). We examined the association between hearing sensitivity and cognitive functions with sentence-in-noise perception using a multivariable linear regression model adjusted for age, sex, and multiple potential confounders.

RESULTS

Better hearing sensitivity was associated with better speech-in-noise perception (0.25 signal noise ratio [SNR] dB HL decrease per 5 dB HL decrease in PTA; 95% confidence interval [CI]: 0.20 to 0.25; p < 0.001). Better cognitive performance was also associated with better speech-in-noise perception, but to a lesser extent. Crystallized intelligence (MWT-B) showed an effect size of -0.10 SNR dB HL decrease per SD (95% CI: -0.14 to -0.06; p < 0.001), executive functioning (TMT) of -0.08 SNR dB HL decrease per SD (95% CI: -0.13 to -0.03; p = 0.002), working memory (DS) of -0.04 SNR dB HL decrease per SD (95% CI: -0.08 to -0.003; p = 0.03), and long-term memory (VLMT) of -0.03 SNR dB HL decrease per SD (95% CI: -0.07 to 0.01; p = 0.12). The standardized effect of hearing sensitivity (ß = 0.34) on speech-in-noise perception was four to five times larger than the effects of crystallized intelligence (ß = -0.08) and executive functioning (ß = -0.06).

CONCLUSIONS

Hearing sensitivity was the strongest determinant of sentence-in-noise perception in adults above the age of 30. We determined the relative effect of different cognitive functions on sentence-in-noise perception. Crystallized intelligence and executive functions showed stronger associations while working and long-term memory functions had much smaller independent effects. Our results contribute to the understanding of determinants of speech-in-noise perception in aging adults.

Speech Perception in Noise Is Associated With Different Cognitive Abilities in Chinese-Speaking Older Adults With and Without Hearing Aids

Chinese-speaking older adults usually do not perceive a hearing problem until audiometric thresholds exceed 45 dB HL, and the audiometric thresholds of the average hearing-aid (HA) user often exceed 60 dB HL. The purpose of this study was to examine the relationships between cognitive and hearing functions (measured as audiometric or speech reception thresholds) in older Chinese adults with HAs and with untreated hearing loss (HL). Participants were 49 Chinese older adults who used HAs and had moderate to severe HL (HA group), and 46 older Chinese who had mild to moderately severe HL but did not use HAs (untreated; or UT group). Multiple linear regression analysis was employed to evaluate how well age, education level, audiometric thresholds, and speech perception in noise were related to performance on general cognitive function, working memory, executive function, attention, and verbal learning tests. Results showed that speech perception in noise alone accounted for 13–25% of the variance in general cognitive function, working memory, and executive function in the UT group, and 9–21% of the variance in general cognitive function and verbal learning in the HA group (i.e., medium effect sizes). Audiometric thresholds did not explain any proportion of the variance in cognitive functioning in the HA or UT group. Thus, speech perception in noise accounts for more variance in cognitive performance than audiometric thresholds, and is significantly associated with different cognitive functions in older Chinese adults with HAs and with untreated HL.

Predictive Sentence Context Reduces Listening Effort in Older Adults With and Without Hearing Loss and With High and Low Working Memory Capacity

OBJECTIVES

Listening effort is needed to understand speech that is degraded by hearing loss, a noisy environment, or both. This in turn reduces cognitive spare capacity, the amount of cognitive resources available for allocation to concurrent tasks. Predictive sentence context enables older listeners to perceive speech more accurately, but how does contextual information affect older adults' listening effort? The current study examines the impacts of sentence context and cognitive (memory) load on sequential dual-task behavioral performance in older adults. To assess whether effects of context and memory load differ as a function of older listeners' hearing status, baseline working memory capacity, or both, effects were compared across separate groups of participants with and without hearing loss and with high and low working memory capacity.

DESIGN

Participants were older adults (age 60-84 years; n = 63) who passed a screen for cognitive impairment. A median split classified participants into groups with high and low working memory capacity. On each trial, participants listened to spoken sentences in noise and reported sentence-final words that were either predictable or unpredictable based on sentence context, and also recalled short (low-load) or long (high-load) sequences of digits that were presented visually before each spoken sentence. Speech intelligibility was quantified as word identification accuracy, and measures of listening effort included digit recall accuracy, and response time to words and digits. Correlations of context benefit in each dependent measure with working memory and vocabulary were also examined.

RESULTS

Across all participant groups, accuracy and response time for both word identification and digit recall were facilitated by predictive context, indicating that in addition to an improvement in intelligibility, listening effort was also reduced when sentence-final words were predictable. Effects of predictability on all listening effort measures were observed whether or not trials with an incorrect word identification response were excluded, indicating that the effects of predictability on listening effort did not depend on speech intelligibility. In addition, although cognitive load did not affect word identification accuracy, response time for word identification and digit recall, as well as accuracy for digit recall, were impaired under the high-load condition, indicating that cognitive load reduced the amount of cognitive resources available for speech processing. Context benefit in speech intelligibility was positively correlated with vocabulary. However, context benefit was not related to working memory capacity.

CONCLUSIONS

Predictive sentence context reduces listening effort in cognitively healthy older adults resulting in greater cognitive spare capacity available for other mental tasks, irrespective of the presence or absence of hearing loss and baseline working memory capacity.

Cognitive Measures and the Acceptable Noise Level

OBJECTIVE

The aim of this study was to determine the relation between the acceptable noise level (ANL) and cognitive measures of auditory attention and working memory.

DESIGN

Young adults were administered the following tests: the ANL, the Digit Span and Letter-Number Sequencing subtests of the Wechsler Adult Intelligence Scale-Fourth Edition, the Auditory Attention subtest from the Woodcock-Johnson Tests of Cognitive Abilities, the Hearing in Noise Test (HINT), and the operation span (OSPAN) test. A correlation matrix was constructed using Pearson coefficients.

STUDY SAMPLE

Twenty-four young adults aged 20-29 years with normal hearing participated in the study.

RESULTS

No significant relationships were found among the ANL and the different cognitive tasks, nor was there a significant relation found between the ANL and the HINT. However, significant relationships were found between individual cognitive tasks. There was a significant relation found between selective attention and the most comfortable level of presentation of a story.

CONCLUSION

Selective attention may be a key cognitive function in acceptance of background noise.

The Impact of Music Training and Working Memory on Speech Recognition in Older Age

Purpose Music training has been proposed as a possible tool for auditory training in older adults, as it may improve both auditory and cognitive skills. However, the evidence to support such benefits is mixed. The goal of this study was to determine the differential effects of lifelong musical training and working memory on speech recognition in noise, in older adults. Method A total of 31 musicians and nonmusicians aged 65-78 years took part in this cross-sectional study. Participants had a normal pure-tone average, with most having high-frequency hearing loss. Working memory (memory capacity) was assessed with the backward Digit Span test, and speech recognition in noise was assessed with three clinical tests (Quick Speech in Noise, Hearing in Noise Test, and Revised Speech Perception in Noise). Results Findings from this sample of older adults indicate that neither music training nor working memory was associated with differences on the speech recognition in noise measures used in this study. Similarly, duration of music training was not associated with speech-in-noise recognition. Conclusions Results from this study do not support the hypothesis that lifelong music training benefits speech recognition in noise. Similarly, an effect of working memory (memory capacity) was not apparent. While these findings may be related to the relatively small sample size, results across previous studies that investigated these effects have also been mixed. Prospective randomized music training studies may be able to better control for variability in outcomes associated with pre-existing and music training factors, as well as to examine the differential impact of music training and working memory for speech-in-noise recognition in older adults.

Dual-Task Accuracy and Response Time Index Effects of Spoken Sentence Predictability and Cognitive Load on Listening Effort

A sequential dual-task design was used to assess the impacts of spoken sentence context and cognitive load on listening effort. Young adults with normal hearing listened to sentences masked by multitalker babble in which sentence-final words were either predictable or unpredictable. Each trial began with visual presentation of a short (low-load) or long (high-load) sequence of to-be-remembered digits. Words were identified more quickly and accurately in predictable than unpredictable sentence contexts. In addition, digits were recalled more quickly and accurately on trials on which the sentence was predictable, indicating reduced listening effort for predictable compared to unpredictable sentences. For word and digit recall response time but not for digit recall accuracy, the effect of predictability remained significant after exclusion of trials with incorrect word responses and was thus independent of speech intelligibility. In addition, under high cognitive load, words were identified more slowly and digits were recalled more slowly and less accurately than under low load. Participants’ working memory and vocabulary were not correlated with the sentence context benefit in either word recognition or digit recall. Results indicate that listening effort is reduced when sentences are predictable and that cognitive load affects the processing of spoken words in sentence contexts.

Visual and Verbal Working Memory and Processing Speed Across the Adult Lifespan: The Effect of Age, Sex, Educational Level, Awakeness, and Hearing Sensitivity

Objective: To strengthen future methodological choices regarding the measurement of cognition within the field of audiology, the current study aimed to examine the effect of, among other things, hearing sensitivity on the backward corsi tapping task (i.e., visual working memory and processing speed) and the letter-number sequencing task (i.e., verbal working memory and processing speed). Design and Study Sample: The backward corsi tapping task and the letter-number sequencing task were administered to 184 participants, aged between 18 and 69 years. The effect of age, sex, educational level, awakeness, and hearing sensitivity on verbal and visual working memory and processing speed was assessed using stepwise multiple regression analyses. Results: For all outcome variables, a decrease in performance was observed with increasing age. For visual and verbal working memory, males outperformed females, whereas no clear sex effect was observed for visual and verbal processing speed. Hearing sensitivity had only a significant impact on visual processing speed. Conclusion: The importance to evaluate cognitive construct validity within audiological research was highlighted. Further research should focus on investigating the associations between speech understanding on the one hand and the backward corsi tapping task and letter-number sequencing task on the other hand.

Individual Differences in Phonetic Plasticity Across Native and Nonnative Contexts

Purpose Individuals vary in their ability to learn the sound categories of nonnative languages (nonnative phonetic learning) and to adapt to systematic differences, such as accent or talker differences, in the sounds of their native language (native phonetic learning). Difficulties with both native and nonnative learning are well attested in people with speech and language disorders relative to healthy controls, but substantial variability in these skills is also present in the typical population. This study examines whether this individual variability can be organized around a common ability that we label "phonetic plasticity." Method A group of healthy young adult participants (N = 80), who attested they had no history of speech, language, neurological, or hearing deficits, completed two tasks of nonnative phonetic category learning, two tasks of learning to cope with variation in their native language, and seven tasks of other cognitive functions, distributed across two sessions. Performance on these 11 tasks was compared, and exploratory factor analysis was used to assess the extent to which performance on each task was related to the others. Results Performance on both tasks of native learning and an explicit task of nonnative learning patterned together, suggesting that native and nonnative phonetic learning tasks rely on a shared underlying capacity, which is termed "phonetic plasticity." Phonetic plasticity was also associated with vocabulary, comprehension of words in background noise, and, more weakly, working memory. Conclusions Nonnative sound learning and native language speech perception may rely on shared phonetic plasticity. The results suggest that good learners of native language phonetic variation are also good learners of nonnative phonetic contrasts. Supplemental Material https://doi.org/10.23641/asha.16606778.

Speech Understanding in Modulated Noise and Speech Maskers as a Function of Cognitive Status in Older Adults

Objectives The purpose of this study was to investigate the impact of different types of maskers on speech understanding as a function of cognitive status in older adults. The hypothesis tested was that individuals with a diagnosis of mild cognitive impairment (MCI) or mild dementia would perform like their age- and hearing status-matched control counterparts in modulated noise but would perform more poorly in the presence of competing speech. Design Participants (n = 39; age range: 55-77 years old) performed a speech-in-noise task and completed two cognitive screening tests and a measure of working memory. Sentences were presented in the presence of two types of maskers (i.e., speech envelope-modulated noise and two-talker, same-sex competing speech). Two analyses were undertaken: (a) a between-groups comparison of individuals diagnosed with MCI/dementia, individuals who failed both cognitive screeners (possible MCI), and age- and hearing status-matched neurologically healthy control individuals and (b) a mixed-model analysis of variance of speech perception performance as a function of working memory capacity. Results The between-groups comparison yielded significant group differences for speech understanding in both masking conditions, with the MCI/dementia group performing more poorly than the neurologically healthy controls and possible MCI groups. A single measure of working memory (Size Comparison Span [SICSPAN]) was correlated with performance on the speech perception task in the competing speech conditions. Conclusions Adults with a diagnosis of MCI or mild dementia performed more poorly on a speech perception task than their age- and hearing status-matched control counterparts in the presence of both maskers, with larger group mean differences when the target speech was presented in a two-talker masker. This suggests increased difficulty understanding speech in the presence of distracting backgrounds for people with MCI/dementia. Future studies should consider how to target this potentially vulnerable population as they may be experiencing increased difficulty communicating in challenging environments.

Auditory closure with visual cues: Relationship with working memory and semantic memory

The role of working memory (WM) and long-term lexical-semantic memory (LTM) in the perception of interrupted speech with and without visual cues, was studied in 29 native English speakers. Perceptual stimuli were periodically interrupted sentences filled with speech noise. The memory measures included an LTM semantic fluency task, verbal WM, and visuo-spatial WM tasks. Whereas perceptual performance in the audio-only condition demonstrated a significant positive association with listeners' semantic fluency, perception in audio-video mode did not. These results imply that when listening to distorted speech without visual cues, listeners rely on lexical-semantic retrieval from LTM to restore missing speech information.

Glimpsing keywords across sentences in noise: A microstructural analysis of acoustic, lexical, and listener factors

This study investigated how acoustic and lexical word-level factors and listener-level factors of auditory thresholds and cognitive-linguistic processing contribute to the microstructure of sentence recognition in unmodulated and speech-modulated noise. The modulation depth of the modulated masker was changed by expanding and compressing the temporal envelope to control glimpsing opportunities. Younger adults with normal hearing (YNH) and older adults with normal and impaired hearing were tested. A second group of YNH was tested under acoustically identical conditions to the hearing-impaired group, who received spectral shaping. For all of the groups, speech recognition declined and masking release increased for later keywords in the sentence, which is consistent with the word position decreases in the signal-to-noise ratio. The acoustic glimpse proportion and lexical word frequency of individual keywords predicted recognition under different noise conditions. For the older adults, better auditory thresholds and better working memory abilities facilitated sentence recognition. Vocabulary knowledge contributed more to sentence recognition for younger than for older adults. These results demonstrate that acoustic and lexical factors contribute to the recognition of individual words within a sentence, but relative contributions vary based on the noise modulation characteristics. Taken together, acoustic, lexical, and listener factors contribute to how individuals recognize keywords during sentences.

Forward Digit Span and Word Familiarity Do Not Correlate With Differences in Speech Recognition in Individuals With Cochlear Implants After Accounting for Auditory Resolution

Purpose In individuals with cochlear implants, speech recognition is not associated with tests of working memory that primarily reflect storage, such as forward digit span. In contrast, our previous work found that vocoded speech recognition in individuals with normal hearing was correlated with performance on a forward digit span task. A possible explanation for this difference across groups is that variability in auditory resolution across individuals with cochlear implants could conceal the true relationship between speech and memory tasks. Here, our goal was to determine if performance on forward digit span and speech recognition tasks are correlated in individuals with cochlear implants after controlling for individual differences in auditory resolution. Method We measured sentence recognition ability in 20 individuals with cochlear implants with Perceptually Robust English Sentence Test Open-set sentences. Spectral and temporal modulation detection tasks were used to assess individual differences in auditory resolution, auditory forward digit span was used to assess working memory storage, and self-reported word familiarity was used to assess vocabulary. Results Individual differences in speech recognition were predicted by spectral and temporal resolution. A correlation was found between forward digit span and speech recognition, but this correlation was not significant after controlling for spectral and temporal resolution. No relationship was found between word familiarity and speech recognition. Forward digit span performance was not associated with individual differences in auditory resolution. Conclusions Our findings support the idea that sentence recognition in individuals with cochlear implants is primarily limited by individual differences in working memory processing, not storage. Studies examining the relationship between speech and memory should control for individual differences in auditory resolution.

The Relative Weight of Temporal Envelope Cues in Different Frequency Regions for Mandarin Disyllabic Word Recognition

Objectives

Acoustic temporal envelope (E) cues containing speech information are distributed across all frequency spectra. To provide a theoretical basis for the signal coding of hearing devices, we examined the relative weight of E cues in different frequency regions for Mandarin disyllabic word recognition in quiet.

Design

E cues were extracted from 30 continuous frequency bands within the range of 80 to 7,562 Hz using Hilbert decomposition and assigned to five frequency regions from low to high. Disyllabic word recognition of 20 normal-hearing participants were obtained using the E cues available in two, three, or four frequency regions. The relative weights of the five frequency regions were calculated using least-squares approach.

Results

Participants correctly identified 3.13-38.13%, 27.50-83.13%, or 75.00-93.13% of words when presented with two, three, or four frequency regions, respectively. Increasing the number of frequency region combinations improved recognition scores and decreased the magnitude of the differences in scores between combinations. This suggested a synergistic effect among E cues from different frequency regions. The mean weights of E cues of frequency regions 1-5 were 0.31, 0.19, 0.26, 0.22, and 0.02, respectively.

Conclusion

For Mandarin disyllabic words, E cues of frequency regions 1 (80-502 Hz) and 3 (1,022-1,913 Hz) contributed more to word recognition than other regions, while frequency region 5 (3,856-7,562) contributed little.

Tracking Cognitive Spare Capacity During Speech Perception With EEG/ERP: Effects of Cognitive Load and Sentence Predictability

OBJECTIVES

Listening to speech in adverse listening conditions is effortful. Objective assessment of cognitive spare capacity during listening can serve as an index of the effort needed to understand speech. Cognitive spare capacity is influenced both by signal-driven demands posed by listening conditions and top-down demands intrinsic to spoken language processing, such as memory use and semantic processing. Previous research indicates that electrophysiological responses, particularly alpha oscillatory power, may index listening effort. However, it is not known how these indices respond to memory and semantic processing demands during spoken language processing in adverse listening conditions. The aim of the present study was twofold: first, to assess the impact of memory demands on electrophysiological responses during recognition of degraded, spoken sentences, and second, to examine whether predictable sentence contexts increase or decrease cognitive spare capacity during listening.

DESIGN

Cognitive demand was varied in a memory load task in which young adult participants (n = 20) viewed either low-load (one digit) or high-load (seven digits) sequences of digits, then listened to noise-vocoded spoken sentences that were either predictable or unpredictable, and then reported the final word of the sentence and the digits. Alpha oscillations in the frequency domain and event-related potentials in the time domain of the electrophysiological data were analyzed, as was behavioral accuracy for both words and digits.

RESULTS

Measured during sentence processing, event-related desynchronization of alpha power was greater (more negative) under high load than low load and was also greater for unpredictable than predictable sentences. A complementary pattern was observed for the P300/late positive complex (LPC) to sentence-final words, such that P300/LPC amplitude was reduced under high load compared with low load and for unpredictable compared with predictable sentences. Both words and digits were identified more quickly and accurately on trials in which spoken sentences were predictable.

CONCLUSIONS

Results indicate that during a sentence-recognition task, both cognitive load and sentence predictability modulate electrophysiological indices of cognitive spare capacity, namely alpha oscillatory power and P300/LPC amplitude. Both electrophysiological and behavioral results indicate that a predictive sentence context reduces cognitive demands during listening. Findings contribute to a growing literature on objective measures of cognitive demand during listening and indicate predictable sentence context as a top-down factor that can support ease of listening.

Effects of Cognitive Load on Pure-Tone Audiometry Thresholds in Younger and Older Adults

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Cognitive load (CL) impairs listeners’ ability to comprehend sentences, recognize words, and identify speech sounds. Recent findings suggest that this effect originates in a disruption of low-level perception of acoustic details. Here, we attempted to quantify such a disruption by measuring the effect of CL (a two-back task) on pure-tone audiometry (PTA) thresholds. We also asked whether the effect of CL on PTA was greater in older adults, on account of their reduced ability to divide cognitive resources between simultaneous tasks. To specify the mechanisms and representations underlying the interface between auditory and cognitive processes, we contrasted CL requiring visual encoding with CL requiring auditory encoding. Finally, the link between the cost of performing PTA under CL, working memory, and speech-in-noise (SiN) perception was investigated and compared between younger and older participants.

Effect of speech in noise training in the auditory and cognitive skills in children with auditory processing disorders

OBJECTIVES

Speech perception in the presence of background noise is identified as one of the most affected auditory processes in children with auditory processing disorders (APD). Mechanism of speech-in-noise perception is extensively studied and is reported to involve different auditory and cognitive skills. However previous research has reported mixed results investigating the relationship between the cognitive skills and speech-in-noise perception in children with APD. The present study intended to study the correlation between the speech-in-noise perception and other auditory and cognitive skills, and also to find the efficacy of speech-in-noise training in other auditory and cognitive skills in children with APD.

METHOD

The study imparted words in noise training utilizing monosyllable and trisyllable words in the presence of speech shaped noise and 4-talker babble. Participants included 20 children with APD, 10 of them in the experimental group who underwent the training and the remaining 10 served as controls. Auditory outcome measures included five behavioural APD tests and four digit span tests to assess cognition.

RESULTS

There was a significant improvement in the speech-in-noise perception measures, temporal processing measures (gap detection test and duration pattern test) and the backward, ascending and descending digit span measures after the training in participants in the experimental group. However, Spearman rank order correlation did not reveal a significant correlation between the speech-in-noise perception scores and any of the auditory or cognitive measures.

CONCLUSION

Even though there was no correlation within and between auditory and cognitive measures, speech-in-noise training improved the temporal processing skills as well as the working memory skills in children with APD supporting the relationship between the said processes. These relationships with evidence from further research could be utilized to design more effective treatment strategies for children with APD.

Interacting effects of frontal lobe neuroanatomy and working memory capacity to older listeners' speech recognition in noise

Many older adults are struggling with understanding spoken language, particularly when background noise interferes with comprehension. In the present study, we investigated a potential interaction between two well-known factors associated with greater speech-in-noise (SiN) reception thresholds in older adults, namely a) lower working memory capacity and b) age-related structural decline of frontal lobe regions. In a sample of older adults (N = 25) and younger controls (N = 13) with normal pure-tone thresholds, SiN reception thresholds and working memory capacity were assessed. Furthermore, T1-weighted structural MR-images were recorded to analyze neuroanatomical traits (i.e., cortical thickness (CT) and cortical surface area (CSA)) of the cortex. As expected, the older group showed greater SiN reception thresholds compared to the younger group. We also found consistent age-related atrophy (i.e., lower CT) in brain regions associated with SiN recognition, namely the superior temporal lobe bilaterally, the right inferior frontal and precentral gyrus, as well as the left superior frontal gyrus. Those older participants with greater atrophy in these brain regions showed greater SiN reception thresholds. Interestingly, the association between CT in the left superior frontal gyrus and SiN reception thresholds was moderated by individual working memory capacity. Older adults with greater working memory capacity benefitted more strongly from thicker frontal lobe regions leading to better SiN recognition. Overall, our results fit well into the literature showing that age-related structural decline in auditory- and cognition-related brain areas is associated with greater SiN reception thresholds in older adults. However, we highlight that this association changes as a function of individual working memory capacity. We therefore believe that future interventions to improve SiN recognition in older adults should take into account the role of the frontal lobe as well as individual working memory capacity.

Listener characteristics differentially affect self-reported and physiological measures of effort associated with two challenging listening conditions

Listeners vary in their ability to understand speech in adverse conditions. Differences in both cognitive and linguistic capacities play a role, but increasing evidence suggests that such factors may contribute differentially depending on the listening challenge. Here, we used multilevel modeling to evaluate contributions of individual differences in age, hearing thresholds, vocabulary, selective attention, working memory capacity, personality traits, and noise sensitivity to variability in measures of comprehension and listening effort in two listening conditions. A total of 35 participants completed a battery of cognitive and linguistic tests as well as a spoken story comprehension task using (1) native-accented English speech masked by speech-shaped noise and (2) nonnative accented English speech without masking. Masker levels were adjusted individually to ensure each participant would show (close to) equivalent word recognition performance across the two conditions. Dependent measures included comprehension tests results, self-rated effort, and electrodermal, cardiovascular, and facial electromyographic measures associated with listening effort. Results showed varied patterns of responsivity across different dependent measures as well as across listening conditions. In particular, results suggested that working memory capacity may play a greater role in the comprehension of nonnative accented speech than noise-masked speech, while hearing acuity and personality may have a stronger influence on physiological responses affected by demands of understanding speech in noise. Furthermore, electrodermal measures may be more strongly affected by affective response to noise-related interference while cardiovascular responses may be more strongly affected by demands on working memory and lexical access.

Errors on a Speech-in-Babble Sentence Recognition Test Reveal Individual Differences in Acoustic Phonetic Perception and Babble Misallocations

OBJECTIVES

The ability to recognize words in connected speech under noisy listening conditions is critical to everyday communication. Many processing levels contribute to the individual listener's ability to recognize words correctly against background speech, and there is clinical need for measures of individual differences at different levels. Typical listening tests of speech recognition in noise require a list of items to obtain a single threshold score. Diverse abilities measures could be obtained through mining various open-set recognition errors during multi-item tests. This study sought to demonstrate that an error mining approach using open-set responses from a clinical sentence-in-babble-noise test can be used to characterize abilities beyond signal-to-noise ratio (SNR) threshold. A stimulus-response phoneme-to-phoneme sequence alignment software system was used to achieve automatic, accurate quantitative error scores. The method was applied to a database of responses from normal-hearing (NH) adults. Relationships between two types of response errors and words correct scores were evaluated through use of mixed models regression.

DESIGN

Two hundred thirty-three NH adults completed three lists of the Quick Speech in Noise test. Their individual open-set speech recognition responses were automatically phonemically transcribed and submitted to a phoneme-to-phoneme stimulus-response sequence alignment system. The computed alignments were mined for a measure of acoustic phonetic perception, a measure of response text that could not be attributed to the stimulus, and a count of words correct. The mined data were statistically analyzed to determine whether the response errors were significant factors beyond stimulus SNR in accounting for the number of words correct per response from each participant. This study addressed two hypotheses: (1) Individuals whose perceptual errors are less severe recognize more words correctly under difficult listening conditions due to babble masking and (2) Listeners who are better able to exclude incorrect speech information such as from background babble and filling in recognize more stimulus words correctly.

RESULTS

Statistical analyses showed that acoustic phonetic accuracy and exclusion of babble background were significant factors, beyond the stimulus sentence SNR, in accounting for the number of words a participant recognized. There was also evidence that poorer acoustic phonetic accuracy could occur along with higher words correct scores. This paradoxical result came from a subset of listeners who had also performed subjective accuracy judgments. Their results suggested that they recognized more words while also misallocating acoustic cues from the background into the stimulus, without realizing their errors. Because the Quick Speech in Noise test stimuli are locked to their own babble sample, misallocations of whole words from babble into the responses could be investigated in detail. The high rate of common misallocation errors for some sentences supported the view that the functional stimulus was the combination of the target sentence and its babble.

CONCLUSIONS

Individual differences among NH listeners arise both in terms of words accurately identified and errors committed during open-set recognition of sentences in babble maskers. Error mining to characterize individual listeners can be done automatically at the levels of acoustic phonetic perception and the misallocation of background babble words into open-set responses. Error mining can increase test information and the efficiency and accuracy of characterizing individual listeners.