Hearing Speech In Noise Research Articles

Advancements of phonetics in the 21st century: Theoretical and empirical issues of spoken word recognition in phonetic research

How do listeners understand what they are hearing? Humans hearing speech perform spoken word recognition, recognizing what words they are hearing in a speech stream in order to understand the meaning. Phonetics refers to the properties of the speech at a detailed level, particularly below the level of segmental phonemic distinctions. In order to recognize spoken words, listeners have to extract information from the detailed acoustic signal in some way, but theories differ about whether listeners extract phonemes, whole words, or other units, by what mechanism, and they differ on what kinds of information are stored in the lexicon. The process of spoken word recognition can be affected by any number of situations such as the speaker or listener being a non-native of the language or dialect, being a child, having a speech/hearing disability, hearing speech in noise, the speech itself containing variability, or many other situations. Any of these situations can shed light on theoretical questions by giving a fuller picture of how listeners recognize words. This chapter examines what we have learned in these first ∼21 years of the 21st century about how phonetics interacts with spoken word recognition.

Speech Illusions in People at Clinical High Risk for Psychosis Linked to Clinical Outcome.

Around 20% of people at clinical high risk (CHR) for psychosis later develop a psychotic disorder, but it is difficult to predict who this will be. We assessed the incidence of hearing speech (termed speech illusions [SIs]) in noise in CHR participants and examined whether this was associated with adverse clinical outcomes. At baseline, 344 CHR participants and 67 healthy controls were presented with a computerized white noise task and asked whether they heard speech, and whether speech was neutral, affective, or whether they were uncertain about its valence. After 2 years, we assessed whether participants transitioned to psychosis, or remitted from the CHR state, and their functioning. CHR participants had a lower sensitivity to the task. Logistic regression revealed that a bias towards hearing targets in stimuli was associated with remission status (OR = 0.21, P = 042). Conversely, hearing SIs with uncertain valence at baseline was associated with reduced likelihood of remission (OR = 7.72. P = .007). When we assessed only participants who did not take antipsychotic medication at baseline, the association between hearing SIs with uncertain valence at baseline and remission likelihood remained (OR = 7.61, P = .043) and this variable was additionally associated with a greater likelihood of transition to psychosis (OR = 5.34, P = .029). In CHR individuals, a tendency to hear speech in noise, and uncertainty about the affective valence of this speech, is associated with adverse outcomes. This task could be used in a battery of cognitive markers to stratify CHR participants according to subsequent outcomes.

Individual factors that impact noise tolerance

One of the most common complaints of patients wearing hearing aids is difficulty hearing speech in noise. Limited information is available on how to program speech in noise programs as fitting formulas are based on quiet environments. In order to understand what settings could optimize programs in background noise, it is important to determine what objective and subjective factors impact speech understanding in noise. This study sought to evaluate what individual factors (personality, working memory, noise tolerance, and speech in noise abilities) might impact person’s tolerance in background noise. Data was collected remotely using questionnaires and equipment that was dropped off at the participant's home due to covid restrictions at the time. A principal component analysis was used to determine clusters of patients based on the examined factors. The goal of finding group factors will be used to determine the best settings to increase a hearing aid user’s tolerance for background noise so they can wear their hearing aids in these environments and hear speech better. Benefits and disadvantages of at home testing will also be discussed.

Discovering the Unmet Needs of People With Difficulties Understanding Speech in Noise and a Normal or Near-Normal Audiogram.

Purpose A proportion of people with a normal audiogram or mild hearing loss (NA-MHL) experience greater-than-expected difficulty hearing speech in noise. This preliminary exploratory study employed a design thinking approach to better understand the clinical pathway and treatment options experienced by this population. Method Exploratory survey data were analyzed from 233 people with NA-MHL who had consulted a clinician and 47 clinicians. Qualitative analysis was performed on interview data from 21 people with NA-MHL and seven clinicians. Results Results revealed that noisy environments, such as restaurants, were where many people experienced listening difficulties. Most people with NA-MHL were not offered a treatment option at their audiology appointment, and their satisfaction with the appointment was diverse. Many clients reported frustration at being told that their hearing was "normal." Data from clinicians showed that there is no standard test protocol for this population, and most felt that they did not have adequate training or resources to help NA-MHL clients. Conclusion This study discusses the research needs regarding the experience of those with NA-MHL, their help-seeking behaviors, and treatment options. Understanding these needs is the first step to designing projects to improve the quality of life of this population.

Adults who report difficulty hearing speech in noise: an exploration of experiences, impacts and coping strategies

Objective: Listening difficulties in noise are common, even in those with clinically normal hearing. There is a suggestion that subjective assessment of hearing difficulties may be more closely associated with listening effort and fatigue rather than objective measures of hearing and/or speech perception. The aim of this study was to better understand these perceptual deficits and experiences of this population.Design: An exploratory survey was distributed to participants with self-reported listening-in-noise difficulties. The primary aim of the survey was to gather information about challenging listening environments, its impact, and preferred rehabilitation strategies. Secondly, responses were compared to their performance on behavioural tasks.Study sample: Fifty adults aged 33–55 (22 females, with normal or near-normal hearing thresholds), completed the survey, and 45 of these performed behavioural tasks.Results: Background noise with conversational content was the most common source of hearing difficulties. Participants expended higher concentration and attention when communicating in noise, and correlations with previously published behavioural data was reported. Social impacts varied, few had sought treatment, and respondents preferred training over devices.Conclusions: Insights gained may provide clinicians and researchers with an understanding of the situations, impacts and non-auditory factors associated with listening-in-noise difficulties, and preferred rehabilitation for these clients.

Individual differences in speech-in-noise perception parallel neural speech processing and attention in preschoolers

From bustling classrooms to unruly lunchrooms, school settings are noisy. To learn effectively in the unwelcome company of numerous distractions, children must clearly perceive speech in noise. In older children and adults, speech-in-noise perception is supported by sensory and cognitive processes, but the correlates underlying this critical listening skill in young children (3–5 year olds) remain undetermined. Employing a longitudinal design (two evaluations separated by ∼12 months), we followed a cohort of 59 preschoolers, ages 3.0–4.9, assessing word-in-noise perception, cognitive abilities (intelligence, short-term memory, attention), and neural responses to speech. Results reveal changes in word-in-noise perception parallel changes in processing of the fundamental frequency (F0), an acoustic cue known for playing a role central to speaker identification and auditory scene analysis. Four unique developmental trajectories (speech-in-noise perception groups) confirm this relationship, in that improvements and declines in word-in-noise perception couple with enhancements and diminishments of F0 encoding, respectively. Improvements in word-in-noise perception also pair with gains in attention. Word-in-noise perception does not relate to strength of neural harmonic representation or short-term memory. These findings reinforce previously-reported roles of F0 and attention in hearing speech in noise in older children and adults, and extend this relationship to preschool children.

Hemispheric Asymmetry of Endogenous Neural Oscillations in Young Children: Implications for Hearing Speech In Noise.

Speech signals contain information in hierarchical time scales, ranging from short-duration (e.g., phonemes) to long-duration cues (e.g., syllables, prosody). A theoretical framework to understand how the brain processes this hierarchy suggests that hemispheric lateralization enables specialized tracking of acoustic cues at different time scales, with the left and right hemispheres sampling at short (25 ms; 40 Hz) and long (200 ms; 5 Hz) periods, respectively. In adults, both speech-evoked and endogenous cortical rhythms are asymmetrical: low-frequency rhythms predominate in right auditory cortex, and high-frequency rhythms in left auditory cortex. It is unknown, however, whether endogenous resting state oscillations are similarly lateralized in children. We investigated cortical oscillations in children (3–5 years; N = 65) at rest and tested our hypotheses that this temporal asymmetry is evident early in life and facilitates recognition of speech in noise. We found a systematic pattern of increasing leftward asymmetry for higher frequency oscillations; this pattern was more pronounced in children who better perceived words in noise. The observed connection between left-biased cortical oscillations in phoneme-relevant frequencies and speech-in-noise perception suggests hemispheric specialization of endogenous oscillatory activity may support speech processing in challenging listening environments, and that this infrastructure is present during early childhood.

Crossed and uncrossed acoustic reflex growth functions in normal-hearing adults, typically developing children, and children with suspected auditory processing disorder

Objective: Previous data suggested that children with suspected auditory processing disorders (APD) often show elevated or absent acoustic reflex thresholds, especially in crossed conditions (e.g. Allen & Allan, 2014). This study further explored these effects by measuring acoustic reflex growth functions (ARGF). Design: Crossed and uncrossed ARGF slopes were obtained by linear fits between reflex amplitudes and increases in activator level from threshold to 15 dB above it. Study sample: Normal-hearing adults, typically developing children and children with reported listening difficulties and suspected of having an APD, participated. Results: The ARGF slopes were shallower in crossed than in uncrossed conditions for all groups but the magnitude of the effect was significantly greater in the children with suspected APD. There were no differences between the typically developing children and the adults. Conclusions: The results suggest shallower ARGFs in children with suspected APD. Given the role of the acoustic reflex in facilitating hearing speech in noise these findings may begin to shed light on physiologic explanations for some of the difficulties that are reported by children with suspected APD.

Need of speech-in-noise testing to assess listening difficulties in older adults

Objective: To assess the need of including speech-in-noise tests in the audiological test battery in older adults and the key factors that affect performance in these tests. Older adults complain significantly more than other age groups regarding difficulties in hearing speech in noise, even in the presence of a normal audiogram. Hearing speech in noise is a very complex function underpinned by high-level, cognitive and analytic processing along with low-level sensory processing. Study design: The design reflected an overview of the effect of aging in the auditory system and the acoustic and cognitive resources required for hearing speech in noise. In addition, a review of key clinical studies of speech-in-noise tests was conducted in older adults. Results: Age affects the peripheral and central auditory system but also the entire brain at a structural, functional and neurochemical level. Listening to speech in noise requires complex and multimodal processing in auditory, linguistic, cognitive and other domains via multiple brain interconnections that are not yet fully understood. There are several different theories and models proposed to explain age related declines in speech-in-noise performance. Listeners may give different scores in speech-in-noise tests depending on the parameters of these tests, e.g. type of speech stimulus (words vs. sentences) and masker (noise, multi-talker babbler). Speech recognition in noise depends on the degree of direct interaction of the target and masker at the cochlear level (energetic masking) and on how well speech can be dissociated from the masker (informational masking). Studies show more pronounced effects of informational masking and of lexical interference in older adults, who also show poorer use of auditory sensory type cues, and require greater listening effort in order to perform speech-in-noise tasks. Conclusion: Assessing older adults with pure tone audiometry only and addressing these difficulties with hearing amplification may not be enough to address older adults’ hearing needs, as this approach does not take into account the higher level impairments contributing to hearing and listening problems. Careful audiological assessment with appropriately chosen speech-in-noise tests, together with audiometry and potentially additional tests, are thus required in order to identify and characterize hearing difficulties in older adults, in order to inform their management plan.

Emergence of biological markers of musicianship with school-based music instruction.

Musician children and adults demonstrate biological distinctions in auditory processing relative to nonmusicians. For example, musician children and adults have more robust neural encoding of speech harmonics, more adaptive sound processing, and more precise neural encoding of acoustically similar sounds; these enhancements may contribute to musicians' linguistic advantages, such as for hearing speech in noise and reading. Such findings have inspired proposals that the auditory and cognitive stimulation induced by musical practice renders musicians enhanced according to biological metrics germane to communication. Cross-sectional methodologies comparing musicians with nonmusicians, however, are limited by the inability to disentangle training-related effects from demographic and innate qualities that may predistinguish musicians. Over the past several years, our laboratory has addressed this problem by examining the emergence of neural markers of musicianship in children and adolescents using longitudinal approaches to track the development of biological indices of speech processing. This work was conducted in partnership with successful community-based music programs, thus avoiding reliance on a synthetic program for the purposes of laboratory study. Outcomes indicate that many of musicians' auditory-related biological enhancements emerge with training and may promote the acquisition of language skills, including in at-risk populations.

Auditory processing disorder: Clinical and international perspective

APD may be considered a developmental, hearing or neurological disorder, depending on etiology, but in all cases, it is a listening difficulty without an abnormality of pure tone sensitivity. It has been variously defined as a disorder of the central auditory system associated with impaired spatial hearing, auditory discrimination, temporal processing, and performance with competing or degraded sounds. Clinical testing typically examines perception, intelligibility and ordering of both speech and non-speech sounds. While deficits in higher-order cognitive, communicative, and language functions are excluded in some definitions, recent consensus accepts that these functions may be inseparable from active listening. Some believe that APD in children is predominantly or exclusively cognitive in origin, while others insist that true APD has its origins within the auditory brainstem. However, children or their carers presenting at clinics typically complain of difficulty hearing speech in noise, remembering or understanding instructions, and attending to sounds. APD usually occurs alongside other developmental disorders (e.g., language impairment) and may be indistinguishable from them. Consequently, clinicians are uncertain how to diagnose or manage APD; both test procedures and interventions vary widely, even within a single clinic. Effective remediation primarily consists of improving the listening environment and providing communication devices.

Auditory Training: Evidence for Neural Plasticity in Older Adults.

Improvements in digital amplification, cochlear implants, and other innovations have extended the potential for improving hearing function; yet, there remains a need for further hearing improvement in challenging listening situations, such as when trying to understand speech in noise or when listening to music. Here, we review evidence from animal and human models of plasticity in the brain's ability to process speech and other meaningful stimuli. We considered studies targeting populations of younger through older adults, emphasizing studies that have employed randomized controlled designs and have made connections between neural and behavioral changes. Overall results indicate that the brain remains malleable through older adulthood, provided that treatment algorithms have been modified to allow for changes in learning with age. Improvements in speech-in-noise perception and cognition function accompany neural changes in auditory processing. The training-related improvements noted across studies support the need to consider auditory training strategies in the management of individuals who express concerns about hearing in difficult listening situations. Given evidence from studies engaging the brain's reward centers, future research should consider how these centers can be naturally activated during training.

Patient‐reported speech in noise difficulties and hyperacusis symptoms and correlation with test results

To compare self-reported symptoms of difficulty hearing speech in noise and hyperacusis in adults with auditory processing disorders (APDs) and normal controls; and to compare self-reported symptoms to objective test results (speech in babble test, transient evoked otoacoustic emission [TEOAE] suppression test using contralateral noise). A prospective case-control pilot study. Twenty-two participants were recruited in the study: 10 patients with reported hearing difficulty, normal audiometry, and a clinical diagnosis of APD; and 12 normal age-matched controls with no reported hearing difficulty. All participants completed the validated Amsterdam Inventory for Auditory Disability questionnaire, a hyperacusis questionnaire, a speech in babble test, and a TEOAE suppression test using contralateral noise. Patients had significantly worse scores than controls in all domains of the Amsterdam Inventory questionnaire (with the exception of sound detection) and the hyperacusis questionnaire (P < .005). Patients also had worse TEOAE suppression test results in both ears than controls; however, this result was not significant after Bonferroni correction. Strong correlations were observed between self-reported symptoms of difficulty hearing speech in noise and speech in babble test results in the right ear (ρ = 0.624, P = .002), and between self-reported symptoms of hyperacusis and TEOAE suppression test results in the right ear (ρ = -0.597 P = .003). There was no significant correlation between the two tests. A strong correlation was observed between right ear speech in babble and patient-reported intelligibility of speech in noise, and right ear TEOAE suppression by contralateral noise and hyperacusis questionnaire.

Neural Encoding of Speech and Music: Implications for Hearing Speech in Noise

Neural Encoding of Speech and Music: Implications for Hearing Speech in Noise

Training to Improve Hearing Speech in Noise: Biological Mechanisms

We investigated training-related improvements in listening in noise and the biological mechanisms mediating these improvements. Training-related malleability was examined using a program that incorporates cognitively based listening exercises to improve speech-in-noise perception. Before and after training, auditory brainstem responses to a speech syllable were recorded in quiet and multitalker noise from adults who ranged in their speech-in-noise perceptual ability. Controls did not undergo training but were tested at intervals equivalent to the trained subjects. Trained subjects exhibited significant improvements in speech-in-noise perception that were retained 6 months later. Subcortical responses in noise demonstrated training-related enhancements in the encoding of pitch-related cues (the fundamental frequency and the second harmonic), particularly for the time-varying portion of the syllable that is most vulnerable to perceptual disruption (the formant transition region). Subjects with the largest strength of pitch encoding at pretest showed the greatest perceptual improvement. Controls exhibited neither neurophysiological nor perceptual changes. We provide the first demonstration that short-term training can improve the neural representation of cues important for speech-in-noise perception. These results implicate and delineate biological mechanisms contributing to learning success, and they provide a conceptual advance to our understanding of the kind of training experiences that can influence sensory processing in adulthood.

Musical Experience and the Aging Auditory System: Implications for Cognitive Abilities and Hearing Speech in Noise

Much of our daily communication occurs in the presence of background noise, compromising our ability to hear. While understanding speech in noise is a challenge for everyone, it becomes increasingly difficult as we age. Although aging is generally accompanied by hearing loss, this perceptual decline cannot fully account for the difficulties experienced by older adults for hearing in noise. Decreased cognitive skills concurrent with reduced perceptual acuity are thought to contribute to the difficulty older adults experience understanding speech in noise. Given that musical experience positively impacts speech perception in noise in young adults (ages 18–30), we asked whether musical experience benefits an older cohort of musicians (ages 45–65), potentially offsetting the age-related decline in speech-in-noise perceptual abilities and associated cognitive function (i.e., working memory). Consistent with performance in young adults, older musicians demonstrated enhanced speech-in-noise perception relative to nonmusicians along with greater auditory, but not visual, working memory capacity. By demonstrating that speech-in-noise perception and related cognitive function are enhanced in older musicians, our results imply that musical training may reduce the impact of age-related auditory decline.

Neural Encoding of Speech and Music: Implications for Hearing Speech in Noise.

Understanding speech in a background of competing noise is challenging, especially for individuals with hearing loss or deficits in auditory processing ability. The ability to hear in background noise cannot be predicted from the audiogram, an assessment of peripheral hearing ability; therefore, it is important to consider the impact of central and cognitive factors on speech-in-noise perception. Auditory processing in complex environments is reflected in neural encoding of pitch, timing, and timbre, the crucial elements of speech and music. Musical expertise in processing pitch, timing, and timbre may transfer to enhancements in speech-in-noise perception due to shared neural pathways for speech and music. Through cognitive-sensory interactions, musicians develop skills enabling them to selectively listen to relevant signals embedded in a network of melodies and harmonies, and this experience leads in turn to enhanced ability to focus on one voice in a background of other voices. Here we review recent work examining the biological mechanisms of speech and music perception and the potential for musical experience to ameliorate speech-in-noise listening difficulties.

Can You Hear Me Now? Musical Training Shapes Functional Brain Networks for Selective Auditory Attention and Hearing Speech in Noise

Even in the quietest of rooms, our senses are perpetually inundated by a barrage of sounds, requiring the auditory system to adapt to a variety of listening conditions in order to extract signals of interest (e.g., one speaker's voice amidst others). Brain networks that promote selective attention are thought to sharpen the neural encoding of a target signal, suppressing competing sounds and enhancing perceptual performance. Here, we ask: does musical training benefit cortical mechanisms that underlie selective attention to speech? To answer this question, we assessed the impact of selective auditory attention on cortical auditory-evoked response variability in musicians and non-musicians. Outcomes indicate strengthened brain networks for selective auditory attention in musicians in that musicians but not non-musicians demonstrate decreased prefrontal response variability with auditory attention. Results are interpreted in the context of previous work documenting perceptual and subcortical advantages in musicians for the hearing and neural encoding of speech in background noise. Musicians’ neural proficiency for selectively engaging and sustaining auditory attention to language indicates a potential benefit of music for auditory training. Given the importance of auditory attention for the development and maintenance of language-related skills, musical training may aid in the prevention, habilitation, and remediation of individuals with a wide range of attention-based language, listening and learning impairments.

Hearing Speech in Noise: Seeing a Loud Talker is Better

Seeing the talker improves the intelligibility of speech degraded by noise (a visual speech benefit). Given that talkers exaggerate spoken articulation in noise, this set of two experiments examined whether the visual speech benefit was greater for speech produced in noise than in quiet. We first examined the extent to which spoken articulation was exaggerated in noise by measuring the motion of face markers as four people uttered 10 sentences either in quiet or in babble-speech noise (these renditions were also filmed). The tracking results showed that articulated motion in speech produced in noise was greater than that produced in quiet and was more highly correlated with speech acoustics. Speech intelligibility was tested in a second experiment using a speech-perception-in-noise task under auditory-visual and auditory-only conditions. The results showed that the visual speech benefit was greater for speech recorded in noise than for speech recorded in quiet. Furthermore, the amount of articulatory movement was related to performance on the perception task, indicating that the enhanced gestures made when speaking in noise function to make speech more intelligible.

Biological Markers of Reading and Speech-in-Noise Perception in the Auditory System

Biological Markers of Reading and Speech-in-Noise Perception in the Auditory System