Speech In Noise Research Articles

Esteem® Active Middle Ear Implant versus Conventional Hearing Aids: Long-Term Performance.

The totally implantable active middle ear implant Esteem® may be considered an effective alternative to conventional hearing aids (cHAs) to manage moderate-to-severe forms of sensorineural hearing loss. This study aimed to provide long-term comparative data of Esteem performances with those achieved by cHA. From a total of 46 subjects who received unilateral application of Esteem®, and were followed up over the years, ten underwent an audiological assessment that compared the outcomes with those achieved in the contralateral ear by a cHA, considering the initially symmetric auditory thresholds in both ears. Other than pure tone audiometry and speech audiometry in quiet, the assessment was performed by using the adaptive speech in noise, i.e., Matrix test. The mean speech intelligibility in quiet shows in the unaided situation a recognition of 50.7% at 71 dBHL, 71% at 69 dBHL with only contralateral cHA, 92% at 66 dBHL with only Esteem device and 94% at 61 dBHL with Esteem® device and contralateral cHA. The mean speech intelligibility in noise shows in the unaided situation a recognition of 36% at 71 dBHL, 56% at 69 dBHL with only contralateral cHA, 79% at 66 dBHL with only Esteem® device and 84% at 61 dBHL with Esteem® device and contralateral cHA. At Matrix test in the unaided condition, 4 patients reached 50% of intelligibility and the 50% threshold was obtained with a mean sound/noise ratio of +10 dBHL. In the contralaterally aided condition, 10 patients reached a 50% threshold in a condition of mean S/N ratio of +10.6 dBHL. In the Esteem® only and Esteem® plus cHA condition, all patients reached the 50% threshold with a mean S/N ratio of +3.4 dBHL with the Esteem® device and +0.92 dBHL with Esteem® plus a contralateral cHA, with a statistically nonsignificant difference. The mean deviation from the reference value (7.1 dB in the normal hearing population) was 17.1 dBHL, in unaided situation; this condition did not change with only the contralateral cHA (17.6 dBHL), whilst a significant improvement could be identified with only Esteem® device, where the mean deviation was 10.5 dBHL, and mostly with Esteem® device associated with the contralateral cHA, with a value of 8.02 dBHL. The adaptive speech audiometry in noise (Matrix Test) showed that binaural stimulation provides greater benefits in the speech recognition in noise test in comparison to monaural stimulation, especially when this is carried out only by the cHA. However, the Esteem® device allowed to obtain audiological benefits that are significantly superior to those offered by cHAs, especially in cases where the hearing loss is severe and, in some cases, profound, achieving performances almost comparable to those of a cochlear implant.

The Impact of Selective Attention and Musical Training on the Cortical Speech Tracking in the Delta and Theta Frequency Bands.

Oral communication regularly takes place amidst background noise, requiring the ability to selectively attend to a target speech stream. Musical training has been shown to be beneficial for this task. Regarding the underlying neural mechanisms, recent studies showed that the speech envelope is tracked by neural activity in auditory cortex, which plays a role in the neural processing of speech, including speech in noise. The neural tracking occurs predominantly in two frequency bands, the delta and the theta bands. However, much regarding the specifics of these neural responses, as well as their modulation through musical training, still remain unclear. Here, we investigated the delta- and theta-band cortical tracking of the speech envelope of attended and ignored speech using magnetoencephalography (MEG) recordings. We thereby assessed both musicians and nonmusicians to explore potential differences between these groups. The cortical speech tracking was quantified through source-reconstructing the MEG data and subsequently relating the speech envelope in a certain frequency band to the MEG data using linear models. We thereby found the theta-band tracking to be dominated by early responses with comparable magnitudes for attended and ignored speech, whereas the delta band tracking exhibited both earlier and later responses that were modulated by selective attention. Almost no significant differences emerged in the neural responses between musicians and nonmusicians. Our findings show that only the speech tracking in the delta but not in the theta band contributes to selective attention, but that this mechanism is essentially unaffected by musical training.

Distinct roles of SNR, speech Intelligibility, and attentional effort on neural speech tracking in noise.

Robust neural encoding of speech in noise is influenced by several factors, including signal-to-noise ratio (SNR), speech intelligibility (SI), and attentional effort (AE). Yet, the interaction and distinct role of these factors remain unclear. In this study, fourteen native English speakers performed selective speech listening tasks at various SNR levels while EEG responses were recorded. Attentional performance was assessed using a repeated word detection task, and attentional effort was inferred from subjects' gaze velocity. Results indicate that both SNR and SI enhance neural tracking of target speech, with distinct effects influenced by the previously overlooked role of attentional effort. Specifically, at high levels of SI, increasing SNR leads to reduced attentional effort, which in turn decreases neural speech tracking. Our findings highlight the importance of differentiating the roles of SNR, SI, and AE in neural speech processing and advance our understanding of how noisy speech is processed in the auditory pathway.

Auditory processing abilities of children with congenital blindness

BackgroundChildren with visual challenges rely on their hearing ability to accomplish daily tasks more efficiently. Many investigations show changes in the auditory pathway in children and adults with early blindness. It can be hypothesized that the auditory processing abilities of children with congenital blindness will be superior to those of typically developing children without any visual challenges. PurposeThe current study was designed to compare some of the auditory processing abilities of children with congenital blindness and typically developing children who do not have any visual challenges. Specifically, the study compared the perception of speech in noise, temporal patterning ability, binaural integration ability as well as auditory memory and sequencing abilities of children in two groups. Research designIt was a prospective cross-sectional study comparing two groups. Study sampleA total of 160 children, 80 typically developing children without any visual challenges (reference group) and 80 children with congenital blindness, in the age range of 7–11 years, participated in the study. Data collection and analysisPitch pattern test (PPT), perception of speech perception in noise test in Marathi (PSIN-M), dichotic digit test in Marathi (DDT-M), and auditory memory and sequencing test in Marathi (AMST-M) were administered. Independent sample T test and Mann Whitney U test were used to compare the performance of the two groups on these tests. ResultsChildren with congenital blindness showed significantly better scores on PPT, PSIN-M, and DDT-M as compared to children in the reference group in all the age groups. A clear trend was not observed on DDT-M. ConclusionIt can be concluded that children with congenital blindness have better auditory processing, auditory memory, and sequencing abilities compared to typically developing children without any visual challenges.

Interference of mid-level sound statistics underlie human speech recognition sensitivity in natural noise.

Recognizing speech in noise, such as in a busy restaurant, is an essential cognitive skill where the task difficulty varies across environments and noise levels. Although there is growing evidence that the auditory system relies on statistical representations for perceiving 1-5 and coding4,6-9 natural sounds, it's less clear how statistical cues and neural representations contribute to segregating speech in natural auditory scenes. We demonstrate that human listeners rely on mid-level statistics to segregate and recognize speech in environmental noise. Using natural backgrounds and variants with perturbed spectro-temporal statistics, we show that speech recognition accuracy at a fixed noise level varies extensively across natural backgrounds (0% to 100%). Furthermore, for each background the unique interference created by summary statistics can mask or unmask speech, thus hindering or improving speech recognition. To identify the neural coding strategy and statistical cues that influence accuracy, we developed generalized perceptual regression, a framework that links summary statistics from a neural model to word recognition accuracy. Whereas a peripheral cochlear model accounts for only 60% of perceptual variance, summary statistics from a mid-level auditory midbrain model accurately predicts single trial sensory judgments, accounting for more than 90% of the perceptual variance. Furthermore, perceptual weights from the regression framework identify which statistics and tuned neural filters are influential and how they impact recognition. Thus, perception of speech in natural backgrounds relies on a mid-level auditory representation involving interference of multiple summary statistics that impact recognition beneficially or detrimentally across natural background sounds.

The effect of speech and non-speech noise on comprehension of storybook reading for elementary school children

Children are generally more affected by surrounding noise than are adults, and are more disturbed by speech than by non-speech noise. Storybook reading, which is one of the main activities in school curricula, is known to improve children's language skills, social abilities, and behavior. However, classrooms are generally noisy environments, and the effectiveness of storybook reading in noise is unclear. This study aimed to investigate how noise affects storybook reading comprehension among elementary schoolchildren. A practiced speaker read picture books to 11 elementary school schoolchildren (age range, 6-9 years) under three listening conditions: quiet, speech noise (babble noise), and non-speech noise (noise recorded in a boiler room). A comprehension test (e.g., story flow, character behaviors, keywords) was conducted after each book was read. No significant difference in story comprehension scores was found among the listening conditions, likely because the visual information helped the children understand the stories even in noise. However, the story comprehension score under the speech noise condition was significantly higher for children who frequently played outside as compared with inside. These results suggest that children's comprehension of storybook reading in noise is affected by not only surrounding noise, but also the play area.

Virtual assessment of phone booths' acoustic performance in laboratory and office environments

The irrelevant speech noise is one of the significant issues affecting workers' productivity and comfort. Acoustic furniture is the most common solution addressing this problem: mobile phone booths and partially closed workstations are two examples. The acoustic performance of such devices is defined with laboratory tests according to ISO 23351-1:2020. The sound power level measured in reverberation rooms with and without the product determines the reduction of speech A-weighted sound power level (DS,A). However, predicting acoustic performance in real-world scenarios is still challenging. The present work explores the discrepancies between DS,A, and apparent speech reduction (D'S,A) through numerical models. The study assesses the performance difference between a calibrated virtual reverberation room and virtual open-plan offices maintaining the same acoustic properties, i.e., sound transmission and sound absorption, of a typical two-person phone booth. Moreover, the study investigates the fluctuation on D'S,A changing main room acoustic criteria, e.g., the reverberation time (T) and the total absorption area (A). Results help define ray-based simulations' reliability in predicting furniture ensembles' acoustic performance.

Outcome Evaluation of BAHA Attract System Implantations.

Bone Anchored Hearing Aids (BAHAs) are currently well-utilized for treatment of hearing-impaired patients with unilateral or bilateral mixed and conductive hearing loss as well as patients with single sided deafness. The objective of this study is to evaluate outcome of BAHA Attract system in terms of surgical, functional,audiological and cosmetic results This is a prospective observational study of 15 consecutive patients of single sided deafness (SSD) who qualified for and underwent BAHA Attract surgery at a tertiary care hospital over a duration of two years. Parameters analysed were: (1) Surgery and wound healing, (2) Post-operative functional results (Bern Benefit for Single sided deafness questionnaire (BBSSQ)), (3) audiological results (free field speech in noise audiometry in two situations: with signal from implanted side and from contralateral side), (4) Cosmetic results (introduction of novel Three Points Scoring System (TPSS). Clinico-radiological planning of surgical site for implant is also described.Mean surgical time was 39 minutes and healing was uneventful in 73 % of patients. All patients reported improvement in all ten hearing situations with maximum improvement for sound localization. Significant improvement of speech in noise was seen especially when signal was presented from implanted side. All patient had full score in TPSS for cosmesis except one patient. This was the same patient in whom clinico-radiologically planned site was discarded intraoperatively due to overpneumatised temporal bone.BAHA Attract system is safeand effective solution for single sided deafness with acceptable cosmesis.

Cochlear Synaptopathy Evaluation With Electrocochleography in Patients With Hearing Difficulty in Noise Despite Normal Hearing Levels.

This study examined patients with normal hearing thresholds who had trouble understanding speech in noise. We used electrocochleography (ECochG) to detect and compare SP/AP amplitude area ratios, a potential indicator of cochlear synaptopathy, and investigate speech perception disorder in noise. The study included 68 people aged between 18 and 65 years, 35 patients and 33 healthy volunteers, who applied to the otorhinolaryngology clinic between November 2023 and March 2024 with a 2-month history of difficulty understanding speech in noisy environments. Everyone was given a tiptrode electrode ECochG test, and the results were compared between groups. An ECochG test was recorded with tiptrode electrodes and was performed on all participants, and the results were compared between groups. In the ECochG test, the summation potential/action potential (SP/AP) amplitude and area ratios of patients who had difficulty understanding speech in a noisy environment were statistically higher than those of the control group. ECochG testing may provide additional evidence to evaluate auditory nerve pathways.

Analysis of the Spanish Auditory Test of Speech in Noise (PAHRE) in a Population with Hearing Loss.

Speech recognition in noise is one of the difficulties faced by people with hearing loss that increases with age. The recently developed Spanish Auditory Test of Speech in Noise (Prueba Auditiva de Habla en Ruido en Español, PAHRE) allows for the identification of these intelligibility difficulties in noise. The aim of this study was to assess speech recognition in noise in people with hearing loss and to test the benefits of the Lombard effect. The participants were 104 people with hearing difficulties, ranging in age from 37 to 98 years. The variables age, degree of hearing loss, presence of high-frequency dropout, and years of formal education were assessed. Psychometric curves were obtained as a function of signal-to-noise ratio as well as threshold values of speech reception as a function of age group for mild and moderate hearing loss. The results indicated that the speech reception threshold increased with both age and the degree of hearing loss, becoming particularly significant after the age of 70. Furthermore, it was found that the combined factors of age, degree of hearing loss, and educational level predicted a high percentage of the variability in the speech reception threshold. Therefore, the Spanish Auditory Test of Speech in Noise could be a useful clinical tool for diagnosis, monitoring, auditory rehabilitation planning, and hearing aid fitting.

Anatomical and behavioural correlates of auditory perception in developmental dyslexia.

Developmental dyslexia is typically associated with difficulties in basic auditory processing and in manipulating speech sounds. However, the neuroanatomical correlates of auditory difficulties in developmental dyslexia (DD) and their contribution to individual clinical phenotypes are still unknown. Recent intracranial electrocorticography findings associated processing of sound amplitude rises and speech sounds with posterior and middle superior temporal gyrus (STG), respectively. We hypothesize that regional STG anatomy will relate to specific auditory abilities in DD, and that auditory processing abilities will relate to behavioral difficulties with speech and reading. One hundred and ten children (78 DD, 32 typically developing, age 7-15 years) completed amplitude rise time and speech in noise discrimination tasks. They also underwent a battery of cognitive tests. Anatomical MRI scans were used to identify regions in which local cortical gyrification complexity correlated with auditory behavior. Behaviorally, amplitude rise time but not speech in noise performance was impaired in DD. Neurally, amplitude rise time and speech in noise performance correlated with gyrification in posterior and middle STG, respectively. Furthermore, amplitude rise time significantly contributed to reading impairments in DD, while speech in noise only explained variance in phonological awareness. Finally, amplitude rise time and speech in noise performance were not correlated, and each task was correlated with distinct neuropsychological measures, emphasizing their unique contributions to DD. Overall, we provide a direct link between the neurodevelopment of the left STG and individual variability in auditory processing abilities in neurotypical and dyslexic populations.

A real-world evaluation of the clinical benefits of improved sound processor technology among Chinese cochlear implant users: A focus on Cochlear Nucleus 7.

Real-world evidence is increasingly used to support clinical and regulatory decisions globally and may be a useful tool to study the unique needs of cochlear implant users in China. The ability to recognize and understand speech in noise is critical for cochlear implant users, however, this remains a challenge in everyday settings with fluctuating competing noise levels. The Cochlear™ Sound Processor, Nucleus® 7 (CP1000), includes Forward Focus, a spatial noise algorithm aimed to improve speech-in-noise performance, and Made for iPhone/iPod/iPad functionality. We conducted a prospective, single-center, open-label, within-participant, real-world evidence investigation in participants with cochlear implants. The primary objective of this study, conducted in China, was to compare speech perception in spatially separated dynamic noise with the Nucleus 7 to the recipients' current older Cochlear Sound Processor, including the Freedom and Nucleus 5 sound processors. A follow-up study monitored participants from the initial study up to 12-months post the fitting of their Nucleus 7 and investigated hearing ability, satisfaction, and usability of the device via a questionnaire. Forty participants were included in the initial study (age-range 3 to 49 years) and 29 continued to the follow-up study (age-range 5 to 28 years). The participants were heterogeneous in terms of age, cochlear implant experience, and duration of hearing loss. Nucleus 7 significantly improved participant speech recognition performance in noise by 7.54 dB when compared with the participants' current older sound processor (p<0.0001). Overall satisfaction with Nucleus 7 was 72%. Satisfaction in different hearing contexts ranged from 93.1% for understanding a 1:1 conversation in a quiet setting, 62.1% for understanding on the phone, to 34.5% hearing in complex noisy situations. The study demonstrated the benefits of the Nucleus 7 sound processor across different hearing environments in a Chinese population and showed improved hearing ability, usability, and satisfaction in a real-world every-day environment.

Pathophysiological processes underlying hidden hearing loss revealed in Kcnt1/2 double knockout mice.

Presbycusis is a prevalent condition in older adults characterized by the progressive loss of hearing due to age-related changes in the cochlea, the auditory portion of the inner ear. Many adults also struggle with understanding speech in noise despite having normal auditory thresholds, a condition termed "hidden" hearing loss because it evades standard audiological assessments. Examination of animal models and postmortem human tissue suggests that hidden hearing loss is also associated with age-related changes in the cochlea and may, therefore, precede overt age-related hearing loss. Nevertheless, the pathological mechanisms underlying hidden hearing loss are not understood, which hinders the development of diagnostic biomarkers and effective treatments for age-related hearing loss. To fill these gaps in knowledge, we leveraged a combination of tools, including transcriptomic profiling and morphological and functional assessments, to identify these processes and examine the transition from hidden to overt hearing loss. As a novel approach, we took advantage of a recently characterized model of hidden hearing loss: Kcnt1/2 double knockout mice. Using this model, we find that even before observable morphological pathology, hidden hearing loss is associated with significant alteration in several processes, notably proteostasis, in the cochlear sensorineural structures, and increased susceptibility to overt hearing loss in response to noise exposure and aging. Our findings provide the first insight into the pathophysiology associated with the earliest and, therefore, most treatable stages of hearing loss and provide critical insight directing future investigation of pharmaceutical strategies to slow and possibly prevent overt age-related hearing loss.

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.

Associations between the medial olivocochlear reflex, middle-ear muscle reflex, and sentence-in-noise recognition using steady and pulsed noise elicitors

The middle-ear muscle reflex (MEMR) and medial olivocochlear reflex (MOCR) modify peripheral auditory function, which may reduce masking and improve speech-in-noise (SIN) recognition. Previous work and our pilot data suggest that the two reflexes respond differently to static versus dynamic noise elicitors. However, little is known about how the two reflexes work in tandem to contribute to SIN recognition. We hypothesized that SIN recognition would be significantly correlated with the strength of the MEMR and with the strength of the MOCR. Additionally, we hypothesized that SIN recognition would be best when both reflexes were activated. A total of 43 healthy, normal-hearing adults met the inclusion/exclusion criteria (35 females, age range: 19–29 years). MEMR strength was assessed using wideband absorbance. MOCR strength was assessed using transient-evoked otoacoustic emissions. SIN recognition was assessed using a modified version of the QuickSIN. All measurements were made with and without two types of contralateral noise elicitors (steady and pulsed) at two levels (50 and 65 dB SPL). Steady noise was used to primarily elicit the MOCR and pulsed noise was used to elicit both reflexes. Two baseline conditions without a contralateral elicitor were also obtained. Results revealed differences in how the MEMR and MOCR responded to elicitor type and level. Contrary to hypotheses, SIN recognition was not significantly improved in the presence of any contralateral elicitors relative to the baseline conditions. Additionally, there were no significant correlations between MEMR strength and SIN recognition, or between MOCR strength and SIN recognition. MEMR and MOCR strength were significantly correlated for pulsed noise elicitors but not steady noise elicitors. Results suggest no association between SIN recognition and the MEMR or MOCR, at least as measured and analyzed in this study. SIN recognition may have been influenced by factors not accounted for in this study, such as contextual cues, warranting further study.

Functional benefits of continuous vs. categorical listening strategies on the neural encoding and perception of noise-degraded speech

Acoustic information in speech changes continuously, yet listeners form discrete perceptual categories to ease the demands of perception. Being a more continuous/gradient as opposed to a more discrete/categorical listener may be further advantageous for understanding speech in noise by increasing perceptual flexibility and resolving ambiguity. The degree to which a listener’s responses to a continuum of speech sounds are categorical versus continuous can be quantified using visual analog scaling (VAS) during speech labeling tasks. Here, we recorded event-related brain potentials (ERPs) to vowels along an acoustic–phonetic continuum (/u/ to /a/) while listeners categorized phonemes in both clean and noise conditions. Behavior was assessed using standard two alternative forced choice (2AFC) and VAS paradigms to evaluate categorization under task structures that promote discrete vs. continuous hearing, respectively. Behaviorally, identification curves were steeper under 2AFC vs. VAS categorization but were relatively immune to noise, suggesting robust access to abstract, phonetic categories even under signal degradation. Behavioral slopes were correlated with listeners’ QuickSIN scores; shallower slopes corresponded with better speech in noise performance, suggesting a perceptual advantage to noise degraded speech comprehension conferred by a more gradient listening strategy. At the neural level, P2 amplitudes and latencies of the ERPs were modulated by task and noise; VAS responses were larger and showed greater noise-related latency delays than 2AFC responses. More gradient responders had smaller shifts in ERP latency with noise, suggesting their neural encoding of speech was more resilient to noise degradation. Interestingly, source-resolved ERPs showed that more gradient listening was also correlated with stronger neural responses in left superior temporal gyrus. Our results demonstrate that listening strategy modulates the categorical organization of speech and behavioral success, with more continuous/gradient listening being advantageous to sentential speech in noise perception.

Age-Related Hearing Loss, Cognitive Decline, and Social Interaction: Testing a Framework.

Aging increases risk for hearing loss, cognitive decline, and social isolation; however, the nature of their interconnection remains unclear. This study examined the interplay between age-related hearing loss, cognitive decline, and social isolation in adults by testing the ability to understand speech in background noise, a challenge frequently reported by many older adults. We analyzed data collected from 128 adults (20-79 years of age, Mage = 51 years) recruited as part of the Aging Brain Cohort at the University of South Carolina repository. The participants underwent testing for hearing, cognition, and social interaction, which included pure-tone audiometry, a words-in-noise (WIN) test, a hearing questionnaire (Speech, Spatial and Qualities of Hearing Scale [SSQ12]), a social questionnaire (Patient-Reported Outcomes Measurement Information System-57 Social), and the Montreal Cognitive Assessment. We used a single pure-tone average (PTA) threshold value and a single WIN threshold value for each participant because there were no differences on average between the left and right ears. Poorer hearing was significantly associated with cognitive decline, through both PTA and WIN thresholds, with a stronger association observed for WIN threshold. Adults with poorer hearing also exhibited greater social isolation, as evidenced by their WIN threshold and SSQ12 score, although not through PTA. This connection was more pronounced with the WIN threshold than with the SSQ12 score. Cognition was not related to social isolation, suggesting that social isolation is affected more by the ability to understand words in noise than by cognition in a nondemented population. Understanding speech in challenging auditory environments rather than mere threshold detection is strongly linked to social isolation and cognitive decline. Thus, inclusion of a word-recognition-in-noise test and a social isolation survey in clinical settings is warranted. https://doi.org/10.23641/asha.26237060.

Degradation in Binaural and Spatial Hearing and Auditory Temporal Processing Abilities as a Function of Aging.

Sensorineural hearing loss is common with advancing age, but even with normal or near normal hearing in older persons, performance deficits are often seen for suprathreshold listening tasks such as understanding speech in background noise or localizing sound direction. This suggests there is also a more central source of the problem. Objectives of this study were to examine as a function of age (young adult to septuagenarian) performance on: 1) a spatial acuity task examining lateralization ability, and a spatial speech-in-noise (SSIN) recognition task, both measured in a hemi-anechoic sound field using a circular horizontal-plane loudspeaker array, and 2) a suprathreshold auditory temporal processing task and a spectro-temporal processing task, both measured under headphones. Further, we examined any correlations between the measures.DesignSubjects were 48 adults, aged 21 to 78, with either normal hearing or only a mild sensorineural hearing loss through 4000 Hz. The lateralization task measured minimum audible angle (MAA) for 500 and 4000 Hz narrowband noise (NBN) bursts in diffuse background noise for both an on-axis (subject facing 0°) and off-axis (facing 45°) listening condition at signal-to-noise ratios (SNRs) of -3, -6, -9, and -12 dB. For 42 of the subjects, SSIN testing was also completed for key word recognition in sentences in multi-talker babble noise; specifically, the separation between speech and noise loudspeakers was adaptively varied to determine the difference needed for 40% and 80% correct performance levels. Finally, auditory temporal processing ability was examined using the Temporal Fine Structure test (44 subjects), and the Spectro-Temporal Modulation test (46 subjects). Mean lateralization performances were poorer (larger MAAs) in older compared to younger subjects, particularly in the more adverse listening conditions (4000 Hz, off-axis, and poorer SNRs). Performance variability was notably higher for older subjects than for young adults. The 4000 Hz NBN bursts produced larger MAAs than did 500 Hz NBN bursts. The SSIN data also showed declining mean performance with age at both criterion levels, with greater variability again found for older subjects. Spearman rho analyses revealed some low to moderate, but significant correlation coefficients for age versus MAA and age versus SSIN results. A low but significant correlation was also observed between the most adverse MAA and SSIN conditions. Results from both the TFS and STM assessments showed decreased mean performance with aging, and revealed moderate, significant correlations, with the strongest relationship shown with the TFS test. Finally, of note, extended-high-frequency (EHF) hearing loss (measured between 9000 and 16,000 Hz) was found in older but not young subjects, and correlated with decreasing performance on several tasks. Particularly for more adverse listening conditions, age-related deficits were found on both of the spatial hearing tasks and in temporal and spectro-temporal processing abilities. It may be that deficits in temporal processing ability contribute to poorer spatial hearing performance in older subjects due to inaccurate coding of binaural/interaural timing information sent from the periphery to the brainstem. In addition, EHF hearing loss may be a coexisting factor in the reduced performance in older subjects.

Alaryngeal Speech Enhancement for Noisy Environments Using a Pareto Denoising Gated LSTM

Loss of the larynx significantly alters natural voice production, requiring alternative communication modalities and rehabilitation methods to restore speech intelligibility and improve the quality of life of affected individuals. This paper explores advances in alaryngeal speech enhancement to improve signal quality and reduce background noise, focusing on individuals who have undergone laryngectomy. In this study, speech samples were obtained from 23 Lithuanian males who had undergone laryngectomy with secondary implantation of the tracheoesophageal prosthesis (TEP). Pareto optimized gated LSTM was trained on tracheoesophageal speech data to recognize complex temporal connections and contextual information in speech signals. The system was able to distinguish between actual speech and various forms of noise and artifacts, resulting in a 25% drop in the mean signal-to-noise ratio (SNR) compared to other approaches. According to acoustic analysis, the system significantly decreased the number of unvoiced frames (PVF) from 40% to 10% while maintaining stable proportions of voiced frames (PVS) and average voicing evidence (AVE), indicating the accuracy of the approach in selectively attenuating noise and undesired speech artifacts while preserving important speech information.

Neuroplasticity of Speech-in-Noise Processing in Older Adults Assessed by Functional Near-Infrared Spectroscopy (fNIRS)

Functional near-infrared spectroscopy (fNIRS), a non-invasive optical neuroimaging technique that is portable and acoustically silent, has become a promising tool for evaluating auditory brain functions in hearing-vulnerable individuals. This study, for the first time, used fNIRS to evaluate neuroplasticity of speech-in-noise processing in older adults. Ten older adults, most of whom had moderate-to-mild hearing loss, participated in a 4-week speech-in-noise training. Their speech-in-noise performances and fNIRS brain responses to speech (auditory sentences in noise), non-speech (spectrally-rotated speech in noise) and visual (flashing chequerboards) stimuli were evaluated pre- (T0) and post-training (immediately after training, T1; and after a 4-week retention, T2). Behaviourally, speech-in-noise performances were improved after retention (T2 vs. T0) but not immediately after training (T1 vs. T0). Neurally, we intriguingly found brain responses to speech vs. non-speech decreased significantly in the left auditory cortex after retention (T2 vs. T0 and T2 vs. T1) for which we interpret as suppressed processing of background noise during speech listening alongside the significant behavioural improvements. Meanwhile, functional connectivity within and between multiple regions of temporal, parietal and frontal lobes was significantly enhanced in the speech condition after retention (T2 vs. T0). We also found neural changes before the emergence of significant behavioural improvements. Compared to pre-training, responses to speech vs. non-speech in the left frontal/prefrontal cortex were decreased significantly both immediately after training (T1 vs. T0) and retention (T2 vs. T0), reflecting possible alleviation of listening efforts. Finally, connectivity was significantly decreased between auditory and higher-level non-auditory (parietal and frontal) cortices in response to visual stimuli immediately after training (T1 vs. T0), indicating decreased cross-modal takeover of speech-related regions during visual processing. The results thus showed that neuroplasticity can be observed not only at the same time with, but also before, behavioural changes in speech-in-noise perception. To our knowledge, this is the first fNIRS study to evaluate speech-based auditory neuroplasticity in older adults. It thus provides important implications for current research by illustrating the promises of detecting neuroplasticity using fNIRS in hearing-vulnerable individuals.