Speech In Noise Research Articles

Individual Listener Preference for Strength of Single-Microphone Noise-Reduction; Trade-off Between Noise Tolerance and Signal Distortion Tolerance.

There are large interindividual variations in preference for strength of noise-reduction (NR). It is hypothesized that each individual's tolerance for background noise on one hand and signal distortions on the other hand form this preference. We aim to visualize and analyze this so-called trade-off between noise attenuation and signal quality. Dutch sentences in stationary background noise were processed with different NR strengths. We used an NR algorithm that allows us to separate the positive effects of NR (noise attenuation) from the negative effects (signal distortion). Stimuli consisted of speech in noise with different degrees of (1) background noise, (2) signal distortions, or (3) both (i.e., realistic NR at different NR strengths). With pairwise comparisons, participants chose which stimulus they preferred for prolonged listening. Twelve listeners with mild to moderate hearing loss participated in the study. For all participants, a trade-off between noise attenuation and signal quality was found and visualized. The strength of preference was estimated with the Bradley-Terry-Luce choice model and was different for all individuals but in the same order of magnitude for distortion effects and noise effects. Strength of preference of realistic NR was smaller by a factor of ten. This study used a unique setup to capture the individual trade-off between noise attenuation and signal quality in NR. Disturbance from signal distortions is as important as disturbance from background noise for determining preference for NR strength. Individual listeners differ in their sensitivity to both factors and as a consequence in their preferred NR strength.

Habilidades auditivas em adultos jovens com e sem percepção de zumbido: um estudo de comparações

ABSTRACT Purpose Objective: To analyze auditory information processing responses in young adult subjects with tinnitus disorder. Methods A descriptive and quantitative study was conducted, involving 36 subjects aged between 19 and 35 years. The subjects were divided into two groups: Group 1 (20 subjects with chronic tinnitus) and Group 2 (16 subjects without tinnitus). All participants underwent medical history assessment, Visual Inspection of the External Auditory Canal, Pure-Tone Audiometry, Speech Audiometry, Acoustic Immittance Measures, and used Behavioral Central Auditory Processing Tests as an evaluation tool - Dichotic Digits Test (TDD), Frequency Pattern Test, Speech in Noise, Masking Level Difference, and Gap in Noise (GIN). Results Statistically significant differences were found between the groups for TDD responses in the left ear and for GIN in both ears. Conclusion Young adults with chronic tinnitus exhibit impairments in binaural integration and temporal resolution skills.

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.

Hybrid Brain–Computer Interface System Using Auditory Stimulation and Speech Imagination Paradigms for Assistive Technology

In the case of paralysis with visual and tactile impairments, brain–computer interfaces (BCIs) based on auditory and mental imagery paradigms are alternative methods for controlling external devices. This study demonstrates the use of a hybrid BCI via auditory stimulation and speech imagination for assistive technology. The proposed auditory BCI using Thai vowel and numeral stimulus patterns as well as multi-loudspeaker position settings for multi-command BCI are investigated. To avoid auditory stimulation during resting periods, a speech imagery method is used to enable an audio stimulator. We observe the classification efficiency of speech imagery and auditory BCIs from selected electroencephalogram channels using the proposed algorithms. We examine the efficiency of using the proposed BCI in the presence of background noise (speech). One command is created using the proposed speech-imagination paradigm. Four commands are created using the proposed auditory stimulation paradigm. We design an experiment to verify the proposed BCI paradigm and classification algorithms for real-time processing. The results show that the average classification accuracy of the proposed auditory BCI using numeral stimuli and scatter patterns without speech noise is 72.2% to 83.3%, respectively. The efficiency under background noise is approximately two times lower than that without background noise.

Blind source separation by long-term monitoring: A variational autoencoder to validate the clustering analysis.

Noise exposure influences the comfort and well-being of people in several contexts, such as work or learning environments. For instance, in offices, different kind of noises can increase or drop the employees' productivity. Thus, the ability of separating sound sources in real contexts plays a key role in assessing sound environments. Long-term monitoring provide large amounts of data that can be analyzed through machine and deep learning algorithms. Based on previous works, an entire working day was recorded through a sound level meter. Both sound pressure levels and the digital audio recording were collected. Then, a dual clustering analysis was carried out to separate the two main sound sources experienced by workers: traffic and speech noises. The first method exploited the occurrences of sound pressure levels via Gaussian mixture model and K-means clustering. The second analysis performed a semi-supervised deep clustering analyzing the latent space of a variational autoencoder. Results show that both approaches were able to separate the sound sources. Spectral matching and the latent space of the variational autoencoder validated the assumptions underlying the proposed clustering methods.

Hearing and Ageing.

Age-related hearing loss (ARHL), or presbycusis, occurs in most mammals, humans included, with a different age of onset and magnitude of loss. It is associated with two major symptoms: loss of sensitivity to sound, especially for high pitches, and a reduced ability to understand speech in background noise. This phenomenon involves both the peripheral structures of the inner ear and the central acoustic pathways. Several mechanisms have been identified as pro-ageing in the human cochlea. The main one is the oxidative stress. The inner ear physiological degeneration can be affected by both intrinsic conditions, such as genetic predisposition, and extrinsic ones, such as noise exposure. The magnitude of neuronal loss precedes and exceeds that of inner hair cell loss, which is also less important than the loss of outer hair cells. Patients with HL often develop atrophy of the temporal lobe (auditory cortex) and brain gliosis can contribute to the development of a central hearing loss. The presence of white matter hyperintensities (WMHs) on the MRI, which is radiologic representation of brain gliosis, can justify a central HL due to demyelination in the superior auditory pathways. Recently, the presence of WMHs has been correlated with the inability to correctly understand words in elderly with normal auditory thresholds.

Quality of Life Impact of Cochlear Implantation for Single-Sided Deafness: Assessing the Interrelationship of Objective and Subjective Measures.

To determine the effect on quality of life (QOL) of cochlear implantation (CI) for single-sided deafness (SSD) and asymmetric hearing loss (AHL) using the first psychometrically developed CI-specific QOL tool for English-speaking patients and to assess its relationship to objective perceptual measures. Retrospective cohort study. Tertiary-care medical center. English-speaking adults with SSD or AHL. Unilateral CI. Cochlear Implant Quality of Life (CIQOL) score, CI-alone speech-in-quiet (SIQ) score (CNC and AzBio), binaural speech-in-noise (SIN) threshold, binaural azimuthal sound localization (SL) error. At the most recent postoperative evaluation (median, 9.3 months postimplantation), 25 of 28 subjects (89%) had a CIQOL improvement, with the improvement considered clinically beneficial (>3 points) for 18 of 28 subjects (64%). Group-mean CIQOL improvement was observed at the first postoperative visit and did not change significantly thereafter. Objective perceptual measures (SL, SIQ, SIN) continued to improve over 12 months after implantation. Linear mixed-model regression analyses showed a moderate positive correlation between SIN and SIQ improvements (r = 0.50 to 0.59, p < 0.0001) and a strong positive correlation between the improvement in the two SIQ measures (r = 0.89, p < 0.0001). No significant relationships were observed ( p > 0.05) among QOL or the objective perceptual measures. QOL improved for the majority of subjects implanted for SSD and AHL. Different time courses for improvement in QOL and audiologic tests, combined with the lack of significant relationships among them, suggest that QOL outcomes reflect different aspects of the CI experience than those captured by speech-understanding and localization measures. SIQ may substitute for SIN when clinical constraints exist.

Design and Development of a Spanish Hearing Test for Speech in Noise (PAHRE)

There are few hearing tests in Spanish that assess speech discrimination in noise in the adult population that take into account the Lombard effect. This study presents the design and development of a Spanish hearing test for speech in noise (Prueba Auditiva de Habla en Ruido en Español (PAHRE) in Spanish). The pattern of the Quick Speech in Noise test was followed when drafting sentences with five key words each grouped in lists of six sentences. It was necessary to take into account the differences between English and Spanish. A total of 61 people (24 men and 37 women) with an average age of 46.9 (range 18-84 years) participated in the study. The work was carried out in two phases. In the first phase, a list of Spanish sentences was drafted and subjected to a familiarity test based on the semantic and syntactic characteristics of the sentences; as a result, a list of sentences was selected for the final test. In the second phase, the selected sentences were recorded with and without the Lombard effect, the equivalence between both lists was analysed, and the test was applied to a first reference population. The results obtained allow us to affirm that it is representative of the Spanish spoken in its variety in peninsular Spain. In addition, these results point to the usefulness of the PAHRE test in assessing speech in noise by maintaining a fixed speech intensity while varying the intensity of the multi-speaker background noise. The incorporation of the Lombard effect in the test shows discrimination differences with the same signal-to-noise ratio compared to the test without the Lombard effect.

Effect of Age and Hearing Loss on Auditory Processing Skills.

Background: The present study aimed to evaluate the effect of age and hearing loss on auditory processing abilities. For this purpose, auditory processing abilities were compared among young and older adults with normal hearing sensitivity and older adults with and without hearing loss. Method: The study comprised 20 normal-hearing young adults (18-25 years), 20 older adults with normal hearing sensitivity (50-70 years), and 20 older adults with mild to moderate sensorineural hearing impairment (50-70 years). All 60 participants underwent gap detection(GDT), dichotic consonant-vowe(DCV)l, speech in noise(SPIN), duration pattern(DPT), and working memory (forward and backward span) tests in a sound treated test room. Results: Results showed that young normal-hearing adults performed significantly better than normal-hearing older adults in SPIN, GDT, DCV, working memory, and DPT. Futher, normal-hearing older individuals performed better than older individuals with hearing impairment on all the auditory processing tests except on the forward span test and DPT. Conclusion: Auditory processing abilities deteriorate with age and hearing loss also has a pronounced effect on most auditory processing abilities.

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.

Clinical Application of the Persian Version of Buffalo Model Questionnaire by examining Its correlation with the Buffalo Model Test Battery

Background and Aim: The Buffalo Model Questionnaire (BMQ) has been proposed for the screening, helping to diagnose and also monitoring the effect of rehabilitation on the improvement of Central Auditory Processing Disorder ((C)APD). In this regard, the applicability and accuracy of Persian-BMQ (P-BMQ) are evaluated by examining the correlation between the results of this questionnaire and the Buffalo model test battery. Methods: Overall, 254 children, normal and with Specific Learning Disorder (SLD) aged between 7–12 years old participated in this cross-sectional study. The questionnaire was completed by the parents of children who were subjected to the Buffalo model test battery evaluations. Results: In the normal group, the highest correlation (0.648) was shown between the Decoding (D) component of the P-BMQ with the Row Staggered Spondaic Word (RSSW) variable. In the SLD group, the highest correlation (0.318) was shown between the Variance-tolerance fading memory (V) component of the P-BMQ and the qualitative Persian version of the Phonemic Sentence Test (P-PST) variable. The highest correlation was considered to be between the D component of the P-BMQ with the Right Competitive word, started in the Left ear (RC-LEF) variable in the SSW test (0.498), and qualitative P-PST variable (0.471); and 0.360 between the V component of the P-BMQ and Persian version of the Speech in Noise with S/N=4 in the Left ear (P-SIN4L) of variable in the P-SIN test. Conclusion: P-BMQ is a useful screening tool complementing the Persian Buffalo model test battery for evaluating auditory processing evaluation in children. Keywords: Central auditory processing disorder; specific learning disorder; Buffalo model questionnaire

Normative Data for Speech-in-Noise Perception Test in Young Adults with Normal Hearing: Gender and Ear Laterality Effects

Background and Aim: Adding noise to the speech audiometry tests increases the sensitivity and specificity of them. This study aimed to investigate the normative data for the Speech-in- Noise (SIN) perception test in normal-hearing adults aged 18–25, and evaluate the effect of gender and ear laterality on the test score. Methods: In this cross-sectional study, 126 adults aged 18–25 years with mean(SD) of age: 22.28(1.61) years old participated. The SIN perception test using Persian monosyllabic words was performed in quiet and using 5 signal-to-noise ratios (SNRs; 0,± 5 and ± 10). Results: The mean of SIN perception score was 96.48, 91 and 82.79% at the SNRs of +10, +5, and 0 for the right ear, and 97.09, 91.42, and 84.11% at the SNRs of +10, +5, and 0 for the left ear, respectively. The interaction effect of gender and ear laterality had no statistically significant effect on the test results in quiet and at any SNRs (p&gt;0.05). Moreover, the main effect of gender on the test score was not significant (p&gt;0.05), and there was no significant difference in the test score between the right and left ears (p&gt;0.05). Conclusion: Given the importance of including the SIN perception test in the routine audiology tests, considering normative data for this test is important. The normative data found in this study for this test can be routinely used in audiology clinics. Keywords: Speech-in-noise recognition; word-in-noise recognition; noise; normative data; gender; laterality

Age-related changes in auditory temporal processing assessed using forward masking

One of the main complaints of older adults is difficulty understanding speech in noise. For older adults with audiometric thresholds within the normal range this difficulty may partly reflect deficits in temporal processing. The purpose of this study was to evaluate the effect of age on the rate of recovery from forward masking. There were seven young participants (four females; mean age 26 years) and seven older participants (six females; mean age 62 years) with normal audiometric thresholds, designated YNH and ONH groups. Signal frequencies of 500, 1000, 2000, and 4000 Hz were used. The level of the 20-ms signal was fixed at 15 dB SL for each participant and frequency. The 200-ms masker was a band of noise centered at the signal frequency with a bandwidth equal to the center frequency. The masker level was varied to determine the masker-to-signal ratio (MSR) required for threshold for masker-signal intervals (MSIs) of 5, 10, 20, 30, and 50 ms. The MSRs were smaller for the ONH group than for the YNH group, perhaps indicating lower processing efficiency for the former. Importantly, there was a significant interaction between MSI and the group. The change in MSR with increasing MSI was greater for the YNH than for the ONH group, indicating poorer temporal resolution for the latter.

Cortical tracking of lexical speech units in a multi-talker background is immature in school-aged children

Children have more difficulty perceiving speech in noise than adults. Whether this difficulty relates to an immature processing of prosodic or linguistic elements of the attended speech is still unclear. To address the impact of noise on linguistic processing per se, we assessed how babble noise impacts the cortical tracking of intelligible speech devoid of prosody in school-aged children and adults.Twenty adults and twenty children (7-9 years) listened to synthesized French monosyllabic words presented at 2.5 Hz, either randomly or in 4-word hierarchical structures wherein 2 words formed a phrase at 1.25 Hz, and 2 phrases formed a sentence at 0.625 Hz, with or without babble noise. Neuromagnetic responses to words, phrases and sentences were identified and source-localized.Children and adults displayed significant cortical tracking of words in all conditions, and of phrases and sentences only when words formed meaningful sentences. In children compared with adults, the cortical tracking was lower for all linguistic units in conditions without noise. In the presence of noise, the cortical tracking was similarly reduced for sentence units in both groups, but remained stable for phrase units. Critically, when there was noise, adults increased the cortical tracking of monosyllabic words in the inferior frontal gyri and supratemporal auditory cortices but children did not.This study demonstrates that the difficulties of school-aged children in understanding speech in a multi-talker background might be partly due to an immature tracking of lexical but not supra-lexical linguistic units.

Perceptual Characteristics of Voice Identification in Noisy Environments

Auditory analysis is an essential method that is used to recognize voice identity in court investigations. However, noise will interfere with auditory perception. Based on this, we selected white noise, pink noise, and speech noise in order to design and conduct voice identity perception experiments. Meanwhile, we explored the impact of the noise type and frequency distribution on voice identity perception. The experimental results show the following: (1) in high signal-to-noise ratio (SNR) environments, there is no significant difference in the impact of noise types on voice identity perception; (2) in low SNR environments, the perceived result of speech noise is significantly different from that of white noise and pink noise, and the interference is more obvious; (3) in the speech noise with a low SNR (−8 dB), the voice information contained in the high-frequency band of 2930~6250 Hz is helpful for achieving accuracy in voice identity perception. These results show that voice identity perception in a better voice transmission environment is mainly based on the acoustic information provided by the low-frequency and medium-frequency bands, which concentrate most of the energy of the voice. As the SNR gradually decreases, a human’s auditory mechanism will automatically expand the receiving frequency range to obtain more effective acoustic information from the high-frequency band. Consequently, the high-frequency information ignored in the objective algorithm may be more robust with respect to identity perception in our environment. The experimental studies not only evaluate the quality of the case voice and control the voice recording environment, but also predict the accuracy of voice identity perception under noise interference. This research provides the theoretical basis and data support for applying voice identity perception in forensic science.

Neurodevelopmental oscillatory basis of speech processing in noise

Humans’ extraordinary ability to understand speech in noise relies on multiple processes that develop with age. Using magnetoencephalography (MEG), we characterize the underlying neuromaturational basis by quantifying how cortical oscillations in 144 participants (aged 5–27 years) track phrasal and syllabic structures in connected speech mixed with different types of noise. While the extraction of prosodic cues from clear speech was stable during development, its maintenance in a multi-talker background matured rapidly up to age 9 and was associated with speech comprehension. Furthermore, while the extraction of subtler information provided by syllables matured at age 9, its maintenance in noisy backgrounds progressively matured until adulthood. Altogether, these results highlight distinct behaviorally relevant maturational trajectories for the neuronal signatures of speech perception. In accordance with grain-size proposals, neuromaturational milestones are reached increasingly late for linguistic units of decreasing size, with further delays incurred by noise.

Cortical Activation in Response to Speech Differs between Prelingually Deafened Cochlear Implant Users with Good or Poor Speech-in-Noise Understanding: An fNIRS Study

Cochlear implant (CI) users with prelingual deafness (hearing impairment started before language development was completed) show variable speech-in-noise (SIN) understanding. The present study aimed to assess cortical activation patterns to speech-in-quiet (SIQ) and SIN in prelingual CI users and compared to individuals with normal hearing (NH), using functional Near-Infrared Spectroscopy (fNIRS). Participants included 15 NH who listened to natural speech, 15 NH who listened via 8-channel noise-excited vocoder, and 14 prelingual CI users. fNIRS data were collected in a block design that included three conditions: SIQ, SIN in a signal-to-noise ratio of 0 dB, and noise. Speech reception thresholds in noise (SRTn) were also assessed. Results revealed different patterns of activation between the NH and CI participants in channels covering mainly the right and left middle temporal gyrus (MTG), depending on the SRTn of the CI users. Specifically, while the NH group showed large response to SIQ and SIN in the MTG areas, prelingual CI users with poor SRTn showed significantly smaller response to SIQ, and inversed response (a reduction in activation) to SIN in the same brain areas. These novel findings support the notion that the MTG can serve as a neural marker for speech understanding in CI patients.

Differences in neural encoding of speech in noise between cochlear implant users with and without preserved acoustic hearing

Cochlear implants (CIs) have evolved to combine residual acoustic hearing with electric hearing. It has been expected that CI users with residual acoustic hearing experience better speech-in-noise perception than CI-only listeners because preserved acoustic cues aid unmasking speech from background noise. This study sought neural substrate of better speech unmasking in CI users with preserved acoustic hearing compared to those with lower degree of acoustic hearing. Cortical evoked responses to speech in multi-talker babble noise were compared between 29 Hybrid (i.e., electric acoustic stimulation or EAS) and 29 electric-only CI users. The amplitude ratio of evoked responses to speech and noise, or internal SNR, was significantly larger in the CI users with EAS. This result indicates that CI users with better residual acoustic hearing exhibit enhanced unmasking of speech from background noise.

User characteristics associated with use of wrist-worn wearables and physical activity apps by adults with and without impaired speech-in-noise recognition: a cross-sectional analysis

Objective To study weekly use of smartwatches, fitness watches and physical activity apps among adults with and without impaired speech-in-noise (SIN) recognition, to identify subgroups of users. Design Cross-sectional study. Study sample Adults (aged 28–80 years) with impaired (n = 384) and normal SIN recognition (n = 341) as measured with a web-based digits-in-noise test, from the Netherlands Longitudinal Study on Hearing. Multiple logistic regression analyses were used to study differences and to build an association model. Results Employed adults in both groups are more likely to use each type of fitness technology (all ORs >3.4, all p-values < 0.004). Specific to fitness watch use, adults living with others use it more (OR 2.5, 95%CI 1.1;5.8, p = 0.033) whereas those abstaining from alcohol (OR 0.3, 95%CI 0.1;0.6) or consuming >2 glasses/week (OR 0.4, 95%CI 0.2;0.81, overall p = 0.006) and hearing aid users (OR 0.5, 95%CI 0.2;0.9, p = 0.024) make less use. Conclusions Subgroups of adults more and less likely to use fitness technology exist, but do not differ between adults with and without impaired SIN recognition. More research is needed to confirm these results and to develop interventions to increase physical activity levels among adults with hearing loss.

The possible role of early-stage phase-locked neural activities in speech-in-noise perception in human adults across age and hearing loss

Ageing affects auditory neural phase-locked activities which could increase the challenges experienced during speech-in-noise (SiN) perception by older adults. However, evidence for how ageing affects SiN perception through these phase-locked activities is still lacking. It is also unclear whether influences of ageing on phase-locked activities in response to different acoustic properties have similar or different mechanisms to affect SiN perception. The present study addressed these issues by measuring early-stage phase-locked encoding of speech under quiet and noisy backgrounds (speech-shaped noise (SSN) and multi-talker babbles) in adults across a wide age range (19–75 years old). Participants passively listened to a repeated vowel whilst the frequency-following response (FFR) to fundamental frequency that has primary subcortical sources and cortical phase-locked response to slowly-fluctuating acoustic envelopes were recorded. We studied how these activities are affected by age and age-related hearing loss and how they are related to SiN performances (word recognition in sentences in noise). First, we found that the effects of age and hearing loss differ for the FFR and slow-envelope phase-locking. FFR was significantly decreased with age and high-frequency (≥ 2 kHz) hearing loss but increased with low-frequency (< 2 kHz) hearing loss, whilst the slow-envelope phase-locking was significantly increased with age and hearing loss across frequencies. Second, potential relationships between the types of phase-locked activities and SiN perception performances were also different. We found that the FFR and slow-envelope phase-locking positively corresponded to SiN performance under multi-talker babbles and SSN, respectively. Finally, we investigated how age and hearing loss affected SiN perception through phase-locked activities via mediation analyses. We showed that both types of activities significantly mediated the relation between age/hearing loss and SiN perception but in distinct manners. Specifically, FFR decreased with age and high-frequency hearing loss which in turn contributed to poorer SiN performance but increased with low-frequency hearing loss which in turn contributed to better SiN performance under multi-talker babbles. Slow-envelope phase-locking increased with age and hearing loss which in turn contributed to better SiN performance under both SSN and multi-talker babbles. Taken together, the present study provided evidence for distinct neural mechanisms of early-stage auditory phase-locked encoding of different acoustic properties through which ageing affects SiN perception.