Low-context Sentences Research Articles

Comparing human and machine speech recognition in noise with QuickSIN.

A test is proposed to characterize the performance of speech recognition systems. The QuickSIN test is used by audiologists to measure the ability of humans to recognize continuous speech in noise. This test yields the signal-to-noise ratio at which individuals can correctly recognize 50% of the keywords in low-context sentences. It is argued that a metric for automatic speech recognizers will ground the performance of automatic speech-in-noise recognizers to human abilities. Here, it is demonstrated that the performance of modern recognizers, built using millions of hours of unsupervised training data, is anywhere from normal to mildly impaired in noise compared to human participants.

Higher reading spans mitigate context effects on lexical processing by low-proficiency L2 learners: a self-paced reading study

AbstractThis study examines context effects on lexical processing by low-proficiency Japanese learners of English during sentence comprehension, and the role of individual differences in verbal working memory (WM). Thirty Japanese learners of English as a second language (L2) and 27 speakers of English as a first language (L1) were recruited for a self-paced reading task with high and low context sentences to assess lexical processing abilities, and a reading span task to measure WM capacities. Bayesian modeling indicated that, at the group level, L2 learners had slower lexical processing times for low context sentences compared to high context ones, especially in the spillover region, while L1 speakers showed no difference. At the individual level, higher WM capacities among L2 learners appeared to mitigate these context effects, supporting the interactive-compensatory model (Stanovich in Read Res Q, 10.2307/747348, 1980; Remedial Spec Educ 5(3):11–19, 10.1177/074193258400500306, 1984). The findings highlight context effects on L2 lexical processing and the crucial role of WM in managing these effects among L2 learners.

The Effect of Hearing Loss and Working Memory Capacity on Context Use and Reliance on Context in Older Adults.

Older adults often complain of difficulty in communicating in noisy environments. Contextual information is considered an important cue for identifying everyday speech. To date, it has not been clear exactly how context use (CU) and reliance on context in older adults are affected by hearing status and cognitive function. The present study examined the effects of semantic context on the performance of speech recognition, recall, perceived listening effort (LE), and noise tolerance, and further explored the impacts of hearing loss and working memory capacity on CU and reliance on context among older adults. Fifty older adults with normal hearing and 56 older adults with mild-to-moderate hearing loss between the ages of 60 and 95 years participated in this study. A median split of the backward digit span further classified the participants into high working memory (HWM) and low working memory (LWM) capacity groups. Each participant performed high- and low-context Repeat and Recall tests, including a sentence repeat and delayed recall task, subjective assessments of LE, and tolerable time under seven signal to noise ratios (SNRs). CU was calculated as the difference between high- and low-context sentences for each outcome measure. The proportion of context use (PCU) in high-context performance was taken as the reliance on context to explain the degree to which participants relied on context when they repeated and recalled high-context sentences. Semantic context helps improve the performance of speech recognition and delayed recall, reduces perceived LE, and prolongs noise tolerance in older adults with and without hearing loss. In addition, the adverse effects of hearing loss on the performance of repeat tasks were more pronounced in low context than in high context, whereas the effects on recall tasks and noise tolerance time were more significant in high context than in low context. Compared with other tasks, the CU and PCU in repeat tasks were more affected by listening status and working memory capacity. In the repeat phase, hearing loss increased older adults' reliance on the context of a relatively challenging listening environment, as shown by the fact that when the SNR was 0 and -5 dB, the PCU (repeat) of the hearing loss group was significantly greater than that of the normal-hearing group, whereas there was no significant difference between the two hearing groups under the remaining SNRs. In addition, older adults with LWM had significantly greater CU and PCU in repeat tasks than those with HWM, especially at SNRs with moderate task demands. Taken together, semantic context not only improved speech perception intelligibility but also released cognitive resources for memory encoding in older adults. Mild-to-moderate hearing loss and LWM capacity in older adults significantly increased the use and reliance on semantic context, which was also modulated by the level of SNR.

Alpha-Band Dynamics of Hearing Aid Wearers Performing the Repeat-Recall Test (RRT).

This study measured electroencephalographic activity in the alpha band, often associated with task difficulty, to physiologically validate self-reported effort ratings from older hearing-impaired listeners performing the Repeat-Recall Test (RRT)-an integrative multipart assessment of speech-in-noise performance, context use, and auditory working memory. Following a single-blind within-subjects design, 16 older listeners (mean age = 71 years, SD = 13, 9 female) with a moderate-to-severe degree of bilateral sensorineural hearing loss performed the RRT while wearing hearing aids at four fixed signal-to-noise ratios (SNRs) of -5, 0, 5, and 10 dB. Performance and subjective ratings of listening effort were assessed for complementary versions of the RRT materials with high/low availability of semantic context. Listeners were also tested with a version of the RRT that omitted the memory (i.e., recall) component. As expected, results showed alpha power to decrease significantly with increasing SNR from 0 through 10 dB. When tested with high context sentences, alpha was significantly higher in conditions where listeners had to recall the sentence materials compared to conditions where the recall requirement was omitted. When tested with low context sentences, alpha power was relatively high irrespective of the memory component. Within-subjects, alpha power was related to listening effort ratings collected across the different RRT conditions. Overall, these results suggest that the multipart demands of the RRT modulate both neural and behavioral measures of listening effort in directions consistent with the expected/designed difficulty of the RRT conditions.

Individual variability in speech recognition with compression and beamforming at positive signal-to-noise ratios

Individuals with hearing loss often struggle to communicate in noisy conditions. Aggressive hearing aid (HA) processing, such as fast-acting wide dynamic range compression (WDRC), may reduce speech recognition under some circumstances, and there is concern about disproportionate reductions in listeners with poor working memory. We investigated how speech recognition is affected when WDRC is combined with highly directional beamforming intended to reduce noise from lateral and rear locations. We also sought to determine how listener factors—working memory, age, and hearing loss—affect such interactions in typical listening conditions, including positive signal-to-noise ratios (SNR) and different spatial noise locations. To-date 22 listeners with mild to moderately severe sensorineural hearing loss repeated low-context sentences (0°) mixed with six-talker interference at + 3 and + 8 dB SNRs, distributed equally in two ( + /−90°) or three ( + /−90°/180°) locations. Wearable HAs presented four signal processing combinations, matched for audibility: microphone directionality (omnidirectional or beamformer) and WDRC (fast- or slow-acting). Data show higher speech recognition with beamforming (re omnidirectional), especially at + 3 dB SNR, regardless of WDRC and spatial locations. Relative contributions of listener factors will be assessed in mixed models in the context of combined signal distortions from HA processing and interferers. [Work supported by NIH-K01DC018324.]

The Effect of Breathy Vocal Quality on Speech Intelligibility and Listening Effort in Background Noise.

Speech perception is challenging under adverse conditions. However, there is limited evidence regarding how multiple adverse conditions affect speech perception. The present study investigated two conditions that are frequently encountered in real-life communication: background noise and breathy vocal quality. The study first examined the effects of background noise and breathiness on speech perception as measured by intelligibility. Secondly, the study tested the hypothesis that both noise and breathiness affect listening effort, as indicated by linear and nonlinear changes in pupil dilation. Low-context sentences were resynthesized to create three levels of breathiness (original, mild-moderate, and severe). The sentences were presented in a fluctuating nonspeech noise with two signal-to-noise ratios (SNRs) of -5 dB (favorable) and -9 dB (adverse) SNR. Speech intelligibility and pupil dilation data were collected from young listeners with normal hearing thresholds. The results demonstrated that a breathy vocal quality presented in noise negatively affected speech intelligibility, with the degree of breathiness playing a critical role. Listening effort, as measured by the magnitude of pupil dilation, showed significant effects with both severe and mild-moderate breathy voices that were independent of noise level. The findings contributed to the literature by demonstrating the impact of vocal quality on the perception of speech in noise. They also highlighted the complex dynamics between overall task demand and processing resources in understanding the combined impact of multiple adverse conditions.

Identifying Listeners Whose Speech Intelligibility Depends on a Quiet Extra Moment After a Sentence.

An extra moment after a sentence is spoken may be important for listeners with hearing loss to mentally repair misperceptions during listening. The current audiologic test battery cannot distinguish between a listener who repaired a misperception versus a listener who heard the speech accurately with no need for repair. This study aims to develop a behavioral method to identify individuals who are at risk for relying on a quiet moment after a sentence. Forty-three individuals with hearing loss (32 cochlear implant users, 11 hearing aid users) heard sentences that were followed by either 2 s of silence or 2 s of babble noise. Both high- and low-context sentences were used in the task. Some individuals showed notable benefit in accuracy scores (particularly for high-context sentences) when given an extra moment of silent time following the sentence. This benefit was highly variable across individuals and sometimes absent altogether. However, the group-level patterns of results were mainly explained by the use of context and successful perception of the words preceding sentence-final words. These results suggest that some but not all individuals improve their speech recognition score by relying on a quiet moment after a sentence, and that this fragility of speech recognition cannot be assessed using one isolated utterance at a time. Reliance on a quiet moment to repair perceptions would potentially impede the perception of an upcoming utterance, making continuous communication in real-world scenarios difficult especially for individuals with hearing loss. The methods used in this study-along with some simple modifications if necessary-could potentially identify patients with hearing loss who retroactively repair mistakes by using clinically feasible methods that can ultimately lead to better patient-centered hearing health care. https://doi.org/10.23641/asha.21644801.

The influence of semantic bias on triple non-identical cognates during reading: Evidence from trilinguals’ eye movements

The current study investigated how the processing of triple cognates (words sharing form and meaning across three languages) is modulated by the semantic bias of sentence context in a reading task. In the study, Polish–German–English trilinguals read English sentences while their eye movements were monitored. The sentences were either semantically biased (high-context) or neutral (low-context) towards target words. The targets were either Polish–German–English cognates whose cross-language form overlap was incomplete (e.g. DIAMENT–DIAMANT–DIAMOND) or English-only controls (e.g. KURCZAK–HÄHNCHEN–CHICKEN). The results revealed a significant effect of context in gaze durations and in total reading time. Importantly, no cognate facilitation effect was identified in any reading measure. The gaze duration data additionally revealed that English-only controls were read slower in low-context sentences than in high-context sentences but gaze durations for cognates were not affected by the sentence context. Thus, prior bilingual findings were only partially replicated in the current study with trilinguals. This suggests that bilingual models of language processing should be carefully adapted to trilinguals. The current data may also mean that non-identical cognates (even those shared across three languages) induce relatively small effects and large samples of participants and items may be needed to detect such effects across reading measures.

Feasibility of Tablet-Based Remote Data Collection Method for Measuring Hearing Aid Preference.

The purpose of this study was to determine the feasibility of a tablet-based remote data collection method for measuring preference for hearing aid signal processing features. Participants were nine individuals with bilateral mild to moderately severe sensorineural hearing loss. Stimuli were spatialized low-context sentences mixed with six-talker babble at two realistic signal-to-noise ratios (3 and 8 dB) and processed through a hearing aid simulator. Preference for full factorial combinations of three common hearing aid processing features (two levels each) was elicited using a paired-comparison task. Participants completed two versions of the experiment: The lab version was completed in a sound-treated booth using a custom MATLAB application on a desktop computer; the remote version was completed in a quiet room in the participant's home, using a custom MATLAB executable application on a tablet. Both versions used the same calibrated headphones. Strict infection control protocols were followed. McNemar's test showed no association between preference and data collection method for the majority of the conditions. Percentage agreement and kappa scores were moderate/fair across most conditions. The results indicated that the remote versus lab versions did not have a systematic effect on preference. However, the relatively low agreement and kappa scores suggested within-subject variability in the outcome (preference). The tablet-based version of remote experimentation was comparable to the lab-based version for eliciting preference for hearing aid signal processing features.

Preference for Combinations of Hearing Aid Signal Processing.

The purpose of this study was to determine how multiple types of signal processing activated together influence listeners' preferences. Participants were adults with mild to moderately severe sensorineural hearing loss. Stimuli were spatialized low-context sentences mixed with six-talker babble at 3 and 8 dB signal-to-noise ratios (SNRs). Stimuli were processed with three common hearing aid processing algorithms: wide dynamic range compression (WDRC), frequency compression (FC), and digital noise reduction (DNR). A full-factorial design with two levels for each algorithm (WDRC & DNR: mild versus strong; FC: ON versus OFF; clinically relevant ranges) was evaluated. Preference was measured using a paired-comparison task within a choice-based conjoint analysis framework. Remote data collection methods were used. A signal fidelity metric quantified the acoustic effects across conditions. At 3 dB SNR, participants preferred a combination of Slow WDRC and Mild DNR, although the mean preference was small (odds ratio close to 1). At both SNRs when Strong DNR was used, Fast WDRC was preferred over Slow WDRC. This may be related to signal fidelity, which was lower for the combination of Fast WDRC and Mild DNR and higher for the combination of Slow WDRC and either Mild DNR or Strong DNR. There was no effect of FC on preference or signal fidelity. WDRC and DNR together influenced both listeners' preferences and signal fidelity in the investigated listening conditions. On average, the small effect sizes suggest that minor fine-tuning adjustments to hearing aid algorithms may not result in a substantial change in clinical outcomes.

Perception of interrupted speech and text: Listener and modality factors.

Interrupted speech and text are used to measure processes of linguistic closure that are important for recognition under adverse backgrounds. The present study compared recognition of speech and text that had been periodically interrupted with matched amounts of silence or white space, respectively. Recognition thresholds were obtained for younger and older adults with normal or simulated/impaired hearing and correlated with recognition of speech-in-babble. Results demonstrate domain-general, age-related processes in linguistic closure affecting high context sentences and domain-specific, hearing-related processes in speech recognition affecting low context sentences. Text recognition captures domain-general linguistic processes in speech recognition susceptible to age-related effects.

Phonological and semantic similarity of misperceived words in babble: Effects of sentence context, age, and hearing loss.

This study investigated how age and hearing loss influence the misperceptions made when listening to sentences in babble. Open-set responses to final words in sentences with low and high context were analyzed for younger adults with normal hearing and older adults with normal or impaired hearing. All groups performed similarly in overall accuracy but differed in error type. Misperceptions for all groups were analyzed according to phonological and semantic properties. Comparisons between groups indicated that misperceptions for older adults were more influenced by phonological factors. Furthermore, older adults with hearing loss omitted more responses. Overall, across all groups, results suggest that phonological confusions most explain misperceptions in low context sentences. In high context sentences, the meaningful sentence context appears to provide predictive cues that reduce misperceptions. When misperceptions do occur, responses tend to have greater semantic similarity and lesser phonological similarity to the target, compared to low context sentences. In this way, semantic similarity may index a postdictive process by which ambiguities due to phonological confusions are resolved to conform to the semantic context of the sentence. These patterns demonstrate that context, age, and hearing loss affect the misperceptions, and potential sentence interpretation, made when listening to sentences in babble.

THE ROLE OF SPEECH-IN-NOISE IN JAPANESE EFL LEARNERS’ LISTENING COMPREHENSION PROCESS AND THEIR USE OF CONTEXTUAL INFORMATION

ABSTRACT This study aims to investigate English as a foreign language (EFL) learners’ use of context information under various noise conditions. The participants were seven Japanese undergraduate students. A noise test adopted from the Speech-Perception-in-Noise (SPIN) test (Kalikow et al., 1977) was used. Four signal-tonoise ratio (SNR) conditions (SNR = 0, 5, 10, 15) and a condition without noise were added to the SPIN test. Data were collected using think-aloud protocol procedures. Some target words presented in the noise test were supported with contextual information, enabling learners to use top-down prediction, whereas others were not supported with contextual information, making it difficult for learners to predict the target words. The results showed that, first, learners used contextual information at all noise levels, but differently in high- and low-context sentences. Second, participants’ listening comprehension was greatly affected by background noise. The scores on the noise test and their confidence levels decreased as the level of noise increased. Third, the participants used contextual information successfully and most frequently when the SNR = 15. It was also found that the tolerance level for noise varied among participants. Implications for listening assessment and teaching are discussed.

Does the Speech Cue Profile Affect Response to Amplitude Envelope Distortion?

Purpose A broad area of interest to our group is to understand the consequences of the "cue profile" (a measure of how well a listener can utilize audible temporal and/or spectral cues for listening scenarios in which a subset of cues is distorted. The study goal was to determine if listeners whose cue profile indicated that they primarily used temporal cues for recognition would respond differently to speech-envelope distortion than listeners who utilized both spectral and temporal cues. Method Twenty-five adults with sensorineural hearing loss participated in the study. The listener's cue profile was measured by analyzing identification patterns for a set of synthetic syllables in which envelope rise time and formant transitions were varied. A linear discriminant analysis quantified the relative contributions of spectral and temporal cues to identification patterns. Low-context sentences in noise were processed with time compression, wide-dynamic range compression, or a combination of time compression and wide-dynamic range compression to create a range of speech-envelope distortions. An acoustic metric, a modified version of the Spectral Correlation Index, was calculated to quantify envelope distortion. Results A binomial generalized linear mixed-effects model indicated that envelope distortion, the cue profile, the interaction between envelope distortion and the cue profile, and the pure-tone average were significant predictors of sentence recognition. Conclusions The listeners with good perception of spectro-temporal contrasts were more resilient to the detrimental effects of envelope compression than listeners who used temporal cues to a greater extent. The cue profile may provide information about individual listening that can direct choice of hearing aid parameters, especially those parameters that affect the speech envelope.

Using the Repeat-Recall Test to Examine Factors Affecting Context Use.

The effect of context on speech processing has been studied using different speech materials and response criteria. The Repeat-Recall Test (RRT) evaluates listener performance using high context (HC) and low context (LC) sentences; this may offer another platform for studying context use (CU). This article aims to evaluate if the RRT may be used to study how different signal-to-noise ratios (SNRs), hearing aid technologies (directional microphone and noise reduction), and listener working memory capacities (WMCs) interact to affect CU on the different measures of the RRT. Double-blind, within-subject repeated measures design. Nineteen listeners with a mild-to-moderately severe hearing loss. The RRT was administered with participants wearing the study hearing aids under two microphone (omnidirectional vs. directional) by two noise reduction (on vs. off) conditions. Speech was presented from 0 degree at 75 dB sound pressure level and a continuous speech-shaped noise from 180 degrees at SNRs of 0, 5, 10, and 15 dB. The order of SNR and hearing aid conditions was counterbalanced across listeners. Each test condition was completed twice in two 2-hour sessions separated by 1 month. CU was calculated as the difference between HC and LC sentence scores for each outcome measure (i.e., repeat, recall, listening effort, and tolerable time). For all outcome measures, repeated measures analyses of variance revealed that CU was significantly affected by the SNR of the test conditions. For repeat, recall, and listening effort measures, these effects were qualified by significant two-way interactions between SNR and microphone mode. In addition, the WMC group significantly affected CU during recall and rating of listening effort, the latter of which was qualified by an interaction between the WMC group and SNR. Listener WMC affected CU on estimates of tolerable time as qualified by significant two-way interactions between SNR and microphone mode. The study supports use of the RRT as a tool for measuring how listeners use sentence context to aid in speech processing. The degree to which context influenced scores on each outcome measure of the RRT was found to depend on complex interactions between the SNR of the listening environment, hearing aid features, and the WMC of the listeners.

Effects of hearing aid processing on speech intelligibility in virtual restaurant settings

Hearing-impaired listeners struggle to understand speech in complex environments like restaurants. Environmental factors (signal-to-noise ratio and reverberation time) and hearing aid processing (digital noise reduction and wide dynamic range compression [WDRC]) have been shown to affect speech intelligibility in these contexts. We examine the independent and synergistic effects of these environmental factors and processing strategies on speech intelligibility. Virtual space techniques were used to build a virtual restaurant. The target talker was located directly in front of the listener and competing talkers were located to the listener’s right in various positions around the restaurant. Signal-to-noise ratio was varied randomly, centered on 0 dB with a standard deviation of 2 dB. Reverberation time was either 0.8 or 1.8 s. Hearing aid processing was simulated using custom software. WDRC was either fast or slow with the following attack/release times: 5/50 ms and 100/2000 ms. Digital noise reduction was either on or off. Customized gain and frequency shaping were applied to the signals. Listeners heard low-context sentences through insert earphones and repeated the target sentence. Responses were scored based on the number of correctly repeated keywords. Preliminary results show that the effect of WDRC depended on reverberation time. [Work supported by NIH.]

Slower Speaking Rate Reduces Listening Effort Among Listeners With Cochlear Implants.

Slowed speaking rate was examined for its effects on speech intelligibility, its interaction with the benefit of contextual cues, and the impact of these factors on listening effort in adults with cochlear implants. Participants (n = 21 cochlear implant users) heard high- and low-context sentences that were played at the original speaking rate, as well as a slowed (1.4× duration) speaking rate, using uniform pitch-synchronous time warping. In addition to intelligibility measures, changes in pupil dilation were measured as a time-varying index of processing load or listening effort. Slope of pupil size recovery to baseline after the sentence was used as an index of resolution of perceptual ambiguity. Speech intelligibility was better for high-context compared to low-context sentences and slightly better for slower compared to original-rate speech. Speech rate did not affect magnitude and latency of peak pupil dilation relative to sentence offset. However, baseline pupil size recovered more substantially for slower-rate sentences, suggesting easier processing in the moment after the sentence was over. The effect of slowing speech rate was comparable to changing a sentence from low context to high context. The effect of context on pupil dilation was not observed until after the sentence was over, and one of two analyses suggested that context had greater beneficial effects on listening effort when the speaking rate was slower. These patterns maintained even at perfect sentence intelligibility, suggesting that correct speech repetition does not guarantee efficient or effortless processing. With slower speaking rates, there was less variability in pupil dilation slopes following the sentence, implying mitigation of some of the difficulties shown by individual listeners who would otherwise demonstrate prolonged effort after a sentence is heard. Slowed speaking rate provides release from listening effort when hearing an utterance, particularly relieving effort that would have lingered after a sentence is over. Context arguably provides even more release from listening effort when speaking rate is slower. The pattern of prolonged pupil dilation for faster speech is consistent with increased need to mentally correct errors, although that exact interpretation cannot be verified with intelligibility data alone or with pupil data alone. A pattern of needing to dwell on a sentence to disambiguate misperceptions likely contributes to difficulty in running conversation where there are few opportunities to pause and resolve recently heard utterances.

Time From Hearing Aid Candidacy to Hearing Aid Adoption: A Longitudinal Cohort Study.

Although many individuals with hearing loss could benefit from intervention with hearing aids, many do not seek or delay seeking timely treatment after the onset of hearing loss. There is limited data-based evidence estimating the delay in adoption of hearing aids with anecdotal estimates ranging from 5 to 20 years. The present longitudinal study is the first to assess time from hearing aid candidacy to adoption in a 28-year ongoing prospective cohort of older adults, with the additional goal of determining factors influencing delays in hearing aid adoption, and self-reported successful use of hearing aids. As part of a longitudinal study of age-related hearing loss, a wide range of demographic, biologic, and auditory measures are obtained yearly or every 2 to 3 years from a large sample of adults, along with family, medical, hearing, noise exposure, and hearing aid use histories. From all eligible participants (age ≥18; N = 1530), 857 were identified as hearing aid candidates either at baseline or during their participation, using audiometric criteria. Longitudinal data were used to track transition to hearing aid candidacy and hearing aid adoption. Demographic and hearing-related characteristics were compared between hearing aid adopters and nonadopters. Unadjusted estimated overall time (in years) to hearing aid adoption and estimated delay times were stratified by demographic and hearing-related factors and were determined using a time-to-event analysis (survival analysis). Factors influencing rate of adoption in any given time period were examined along with factors influencing successful hearing aid adoption. Age, number of chronic health conditions, sex, retirement status, and education level did not differ significantly between hearing aid adopters and nonadopters. In contrast, adopters were more likely than nonadopters to be married, of white race, have higher socioeconomic status, have significantly poorer higher frequency (2.0, 3.0, 4.0, 6.0, and 8.0 kHz) pure-tone averages, poorer word recognition in quiet and competing multi-talker babble, and reported more hearing handicap on the Hearing Handicap Inventory for the Elderly/Adults emotional and social subscales. Unadjusted estimation of time from hearing aid candidacy to adoption in the full participant cohort was 8.9 years (SE ± 0.37; interquartile range = 3.2-14.9 years) with statistically significant stratification for race, hearing as measured by low- and high-frequency pure-tone averages, keyword recognition in low-context sentences in babble, and the Hearing Handicap Inventory for the Elderly/Adults social score. In a subgroup analysis of the 213 individuals who adopted hearing aids and were assigned a success classification, 78.4% were successful. No significant predictors of success were found. The average delay in adopting hearing aids after hearing aid candidacy was 8.9 years. Nonwhite race and better speech recognition (in a more difficult task) significantly increased the delay to treatment. Poorer hearing and more self-assessed hearing handicap in social situations significantly decreased the delay to treatment. These results confirm the assumption that adults with hearing loss significantly delay seeking treatment with hearing aids.

Examining use of context in sentences: The recruitment of perceptual and cognitive-linguistic abilities in younger and older adults

Auditory-verbal contextual information facilitates speech recognition. In everyday listening, perceptual and cognitive-linguistic abilities influence speech recognition, but the role of these abilities in contextual use remains unclear. To assess the use of context, younger and older adults listened to sentences in multitalker babble and identified the final words from either high- or low-predictability sentence frames; difference scores between the two conditions indicate use of context. We also assessed (1) speech processing abilities, including masking release, talker segregation, and auditory-verbal closure, (2) cognitive abilities, including memory, inhibition, and speed of processing, and (3) linguistic abilities, assessed through verbal fluency and vocabulary knowledge. Compared to younger adults, older adults had better contextual use and vocabulary knowledge but had poorer recognition of final words with increasing age. These measures, combined with thresholds and age, were entered as predictor variables to explain performance for high- and low-context sentences. Preliminary results indicate that vocabulary knowledge and auditory-verbal closure were associated with contextual use and final word recognition in low-context sentences, respectively. Final word recognition in high-context sentences involved a combination of abilities. Thus, recruitment of perceptual and cognitive-linguistic abilities depends, in part, on the availability of sentence context. [Work supported by NIH/NIDCD.]

Effects of Task Difficulty on Neural Processes Underlying Semantics: An Event-Related Potentials Study.

Purpose Improving the ability to listen efficiently in noisy environments is a critical goal for hearing rehabilitation. However, understanding of the impact of difficult listening conditions on language processing is limited. The current study evaluated the neural processes underlying semantics in challenging listening conditions. Method Thirty adults with normal hearing completed an auditory sentence processing task in 4-talker babble. Event-related brain potentials were elicited by the final word in high- or low-context sentences, where the final word was either highly expected or not expected, followed by a 4-alternative forced-choice response with either longer (1,000 ms), middle (700 ms), or shorter (400 ms) response time deadlines (RTDs). Results Behavioral accuracy was reduced, and reactions times were faster for shorter RTDs. N400 amplitudes, reflecting ease of lexical access, were larger when elicited by target words in low-context sentences followed by shorter compared with longer RTDs. Conclusions These results reveal that more neural resources are allocated for semantic processing/lexical access when listening difficulty increases. Differences between RTDs may reflect increased attentional allocation for shorter RTDs. These findings suggest that situational listening demands can impact the demands for cognitive resources engaged in language processing, which could significantly impact listener experiences across environments.