Speech In Adverse Conditions Research Articles

Older adults show a more sustained pattern of effortful listening than young adults.

Listening to speech in adverse conditions can be challenging and effortful, especially for older adults. This study examined age-related differences in effortful listening by recording changes in the task-evoked pupil response (TEPR; a physiological marker of listening effort) both at the level of sentence processing and over the entire course of a listening task. A total of 65 (32 young adults, 33 older adults) participants performed a speech recognition task in the presence of a competing talker, while moment-to-moment changes in pupil size were continuously monitored. Participants were also administered the Vanderbilt Fatigue Scale, a questionnaire assessing daily life listening-related fatigue within four domains (social, cognitive, emotional, physical). Normalized TEPRs were overall larger and more steeply rising and falling around the peak in the older versus the young adult group during sentence processing. Additionally, mean TEPRs over the course of the listening task were more stable in the older versus the young adult group, consistent with a more sustained recruitment of compensatory attentional resources to maintain task performance. No age-related differences were found in terms of total daily life listening-related fatigue; however, older adults reported higher scores than young adults within the social domain. Overall, this study provides evidence for qualitatively distinct patterns of physiological arousal between young and older adults consistent with age-related upregulation in resource allocation during listening. A more detailed understanding of age-related changes in the subjective and physiological mechanisms that underlie effortful listening will ultimately help to address complex communication needs in aging listeners. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

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.

Brain activations while processing degraded speech in adults with autism spectrum disorder

Individuals with autism spectrum disorder (ASD) are found to have difficulties in understanding speech in adverse conditions. In this study, we used noise-vocoded speech (VS) to investigate neural processing of degraded speech in individuals with ASD. We ran fMRI experiments in the ASD group and a typically developed control (TDC) group while they listened to clear speech (CS), VS, and spectrally rotated VS (SRVS), and they were requested to pay attention to the heard sentence and answer whether it was intelligible or not. The VS used in this experiment was spectrally degraded but still intelligible, but the SRVS was unintelligible. We recruited 21 right-handed adult males with ASD and 24 age-matched and right-handed male TDC participants for this experiment. Compared with the TDC group, we observed reduced functional connectivity (FC) between the left dorsal premotor cortex and left temporoparietal junction in the ASD group for the effect of task difficulty in speech processing, computed as VS-(CS + SRVS)/2. Furthermore, the observed reduced FC was negatively correlated with their Autism-Spectrum Quotient scores. This observation supports our hypothesis that the disrupted dorsal stream for attentive process of degraded speech in individuals with ASD might be related to their difficulty in understanding speech in adverse conditions.

Speech spoken by familiar people is more resistant to interference by linguistically similar speech.

Understanding speech in adverse conditions is affected by experience-a familiar voice is substantially more intelligible than an unfamiliar voice when competing speech is present, even if the content of the speech (the words) are controlled. This familiar-voice benefit is observed consistently, but its underpinnings are unclear: Do familiar voices simply attract more attention, are they inherently more intelligible because they have predictable acoustic characteristics, or are they more intelligible in a mixture because they are more resistant to interference from other sounds? We recruited pairs of native English-speaking participants who were friends or romantic couples. Participants reported words from closed-set English sentences (i.e., Oldenburg Matrix Test; Zokoll et al., 2013) spoken by a familiar talker (the participant's partner) or an unfamiliar talker. We compared 3 masker conditions that are acoustically similar but differ in their demands: (1) English Oldenburg sentences; (2) Oldenburg sentences in a language incomprehensible to the listener (Russian or Spanish); and (3) unintelligible signal-correlated noise. We adaptively varied the target-to-masker ratio to obtain 50% speech reception thresholds. We observed a large (∼5 dB) familiar-voice benefit when the target and masker were both English sentences. This benefit was attenuated (to ∼2 dB) when the masker was in an incomprehensible language and disappeared when it was signal-correlated noise. These results suggest that familiar voices did not benefit intelligibility because they were more predictable or because they attracted greater attention, rather familiarity with a target voice reduced interference from maskers that are linguistically similar to the target. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Effects of Vocabulary and Implicit Linguistic Knowledge on Speech Recognition in Adverse Listening Conditions.

Purpose This study aims to examine the combined influence of vocabulary knowledge and statistical properties of language on speech recognition in adverse listening conditions. Furthermore, it aims to determine whether any effects identified are more salient at particular levels of signal degradation. Method One hundred three young healthy listeners transcribed phrases presented at 4 different signal-to-noise ratios, which were coded for recognition accuracy. Participants also completed tests of hearing acuity, vocabulary knowledge, nonverbal intelligence, processing speed, and working memory. Results Vocabulary knowledge and working memory demonstrated independent effects on word recognition accuracy when controlling for hearing acuity, nonverbal intelligence, and processing speed. These effects were strongest at the same moderate level of signal degradation. Although listener variables were statistically significant, their effects were subtle in comparison to the influence of word frequency and phonological content. These language-based factors had large effects on word recognition at all signal-to-noise ratios. Discussion Language experience and working memory may have complementary effects on accurate word recognition. However, adequate glimpses of acoustic information appear necessary for speakers to leverage vocabulary knowledge when processing speech in adverse conditions.

The role of listening effort during degraded speech recognition: A comparison of the dual-task and pupillometry paradigms

Listening effort is an increasingly important factor in understanding how people recognize speech in adverse conditions, especially for listeners with hearing impairment (Ohlenforst et al., 2017). However, the link between this basic construct and commonly used measures of listening effort is unclear. We compare two measures: dual-task performance and pupillometry, to investigate the relationship between different techniques for measuring effort and performance recognizing vocoded speech. In the dual-task experiment, participants (n = 26) completed a non-linguistic task (pattern matching) either with or without a concurrent speech task. The same participants completed a pupil task, which tracked changes in pupil size while participants recognized words. Both tasks used natural and noise-vocoded speech at two levels of degradation to vary participants’ ability to perform accurately. We found no relationship between dual-task performance and task-evoked changes in pupil size. However, the level of degradation uniquely predicted effort in the dual task, while accuracy uniquely predicted effort in the pupil task. This suggests that different measures of listening effort are sensitive to different underlying factors, including listening conditions and individual ability. Researchers should thus be aware of the sensitivities of a given task when measuring listening effort.

Does noise sensitivity mediate physiological measures of listening effort?

Listening to speech in background noise is cognitively demanding and has been shown to engage frontal cortical regions associated with selective attention and cognitive control. However, especially for noise-sensitive individuals, the presence of interfering or distracting noise may also provoke anxiety or frustration, and these same frontal cortical regions also participate in brain networks associated with anxiety and distress. Thus, it is not clear whether previous results showing enhanced frontal activity when listening to speech in noise reflect cognitive effort, noise annoyance, or both. In order to investigate the possibility of dissociating these two aspects of listening to speech in adverse conditions, we will examine the degree to which measures of individual differences in personality traits, noise sensitivity, and cognitive capacities (attention, working memory) predict behavioral and physiological measures associated with listening effort and affective response. Specifically, we will record cardiovascular and electroencephalographic responses to listening to speech in three levels of two types of industrial background noise. The noise types differ only in terms of the relative degree of acoustic properties associated with noise annoyance (tonality, sharpness) instantiated mainly through differences at frequencies not overlapping with those of the speech target.

Speech Processing Difficulties in Attention Deficit Hyperactivity Disorder.

The large body of research that forms the ease of language understanding (ELU) model emphasizes the important contribution of cognitive processes when listening to speech in adverse conditions; however, speech-in-noise (SIN) processing is yet to be thoroughly tested in populations with cognitive deficits. The purpose of the current study was to contribute to the field in this regard by assessing SIN performance in a sample of adolescents with attention deficit hyperactivity disorder (ADHD) and comparing results with age-matched controls. This population was chosen because core symptoms of ADHD include developmental deficits in cognitive control and working memory capacity and because these top-down processes are thought to reach maturity during adolescence in individuals with typical development. The study utilized natural language sentence materials under experimental conditions that manipulated the dependency on cognitive mechanisms in varying degrees. In addition, participants were tested on cognitive capacity measures of complex working memory-span, selective attention, and lexical access. Primary findings were in support of the ELU-model. Age was shown to significantly covary with SIN performance, and after controlling for age, ADHD participants demonstrated greater difficulty than controls with the experimental manipulations. In addition, overall SIN performance was strongly predicted by individual differences in cognitive capacity. Taken together, the results highlight the general disadvantage persons with deficient cognitive capacity have when attending to speech in typically noisy listening environments. Furthermore, the consistently poorer performance observed in the ADHD group suggests that auditory processing tasks designed to tax attention and working memory capacity may prove to be beneficial clinical instruments when diagnosing ADHD.

Coping with adversity: Individual differences in the perception of noisy and accented speech.

During speech communication, both environmental noise and nonnative accents can create adverse conditions for the listener. Individuals recruit additional cognitive, linguistic, and/or perceptual resources when faced with such challenges. Furthermore, listeners vary in their ability to understand speech in adverse conditions. In the present study, we compared individuals' receptive vocabulary, inhibition, rhythm perception, and working memory with transcription accuracy (i.e., intelligibility scores) for four adverse listening conditions: native speech in speech-shaped noise, native speech with a single-talker masker, nonnative-accented speech in quiet, and nonnative-accented speech in speech-shaped noise. The results showed that intelligibility scores for similar types of adverse listening conditions (i.e., with the same environmental noise or nonnative-accented speech) significantly correlated with one another. Furthermore, receptive vocabulary positively predicted performance globally across adverse listening conditions, and working memory positively predicted performance for the nonnative-accented speech conditions. Taken together, these results indicate that some cognitive resources may be recruited for all adverse listening conditions, while specific additional resources may be engaged when people are faced with certain types of listening challenges.

Audiovisual Binding for Speech Perception in Noise and in Aging

AbstractSpeech perception involves fusion of multiple sensory inputs, but fusion is not automatic, likely depending on several external and internal factors (e.g., attention, noise, age). In this study, we exploited a specific paradigm in which a short audiovisual context made of coherent or incoherent speech material is displayed before an incongruent audiovisual target likely to provide fusion (McGurk & MacDonald, 1976). We confirmed that incoherent context leads to unbinding, that is, a reduction in the amount of fusion. Importantly, adding acoustic noise in the context though not in the target increases fusion. This suggests that listeners systematically evaluate the reliability of their sensory channels and weight them accordingly in the fusion process. We also showed that older participants display more unbinding than younger participants. We discuss the potential consequences concerning people's ability to understand speech in adverse conditions and relate our findings to a “Binding‐and‐Fusion” model of audiovisual speech perception.

Audiovisual benefit for recognition of speech presented with single-talker noise in older listeners

Older listeners are more affected than younger listeners in their recognition of speech in adverse conditions, such as when they also hear a single-competing speaker. In the present study, we investigated with a speeded response task whether older listeners with various degrees of hearing loss benefit under such conditions from also seeing the speaker they intend to listen to. We also tested, at the same time, whether older adults need postperceptual processing to obtain an audiovisual benefit. When tested in a phoneme-monitoring task with single-talker noise present, older (and younger) listeners detected target phonemes more reliably and more rapidly in meaningful sentences uttered by the target speaker when they also saw the target speaker. This suggests that older adults processed audiovisual speech rapidly and efficiently enough to benefit already during spoken sentence processing. Audiovisual benefits for older adults were similar in size to those observed for younger adults in terms of response latencies, but smaller for detection accuracy. Older adults with more hearing loss showed larger audiovisual benefits. Attentional abilities predicted the size of audiovisual response time benefits in both age groups. Audiovisual benefits were found in both age groups when monitoring for the visually highly distinct phoneme /p/ and when monitoring for the visually less distinct phoneme /k/. Visual speech thus provides segmental information about the target phoneme, but also provides more global contextual information that helps both older and younger adults in this adverse listening situation.

The strength of foreign accent in Czech English under adverse listening conditions

The study connects two major topics in current speech research: foreign accentedness and speech in adverse conditions. We parallel the research in intelligibility of non-native speech, but instead of linguistic unit recognition we focus on the perception of the foreign accent strength. First, the question of type and degree of perceptual deficiencies occurring along with certain types of signal degradation is tackled. Second, we measure correlations between the accent ratings and certain candidate phenomena that may influence them, e.g., articulation rate, temporal patterning, contrasts in sound pressure levels on selected syllables and F0 variation. The impacts of different types of signal degradation help to estimate the role of segmental/suprasegmental information in assessments of foreignness in Czech English. The full appreciation of the strength of foreign accent is apparently not possible without fine phonetic detail on the segmental level. However, certain suprasegmental features of foreignness are robust enough to manifest at severe levels of signal degradation. Pairwise variability indices of vowel durations and variation in F0 tracks seem to guide the listener even better in the degraded than in the ‘clean’ speech signal.

Benefits of Fitting One Versus Two Hearing Aids

Benefits of Fitting One Versus Two Hearing Aids

Noise reduction for digital hearing aids

The normal-hearing system extracts monaural and binaural features from the signals at the left and right ears in order to separate and classify sound sources. Robustness of source extraction is achieved by exploiting redundancies in the source signals (auditory scene analysis). ASA is closely related to the ‘‘Cocktail Party Effect,’’ i.e., the ability of normal-hearing listeners to perceive speech in adverse conditions at low signal-to-noise ratios. Hearing-impaired people show a reduced ability to understand speech in noisy environments, stressing the necessity to incorporate noise reduction schemes into hearing aids. Several algorithms for monaural, binaural and multichannel noise reduction have been proposed, which aim at increasing speech intelligibility in adverse conditions. A summary of recent algorithms including directional microphones, beamformers, monaural noise reduction and perceptual model-based binaural schemes will be given. In practice, these schemes were shown to be much less efficient than the normal-hearing system in acoustically complex environments characterized by diffuse noise and reverberation. One reason might be that redundancies in the source signals exploited by the hearing system are not used so far by noise reduction algorithms. Novel multidimensional statistical filtering algorithms are introduced that might fill this gap in the future. [Work supported by BMBF 01EZ0212.]