Examining sound levels across different time scales measured from body-worn dosimetersa).

Studies are increasingly investigating listeners' acoustic environments using real-world data collection methods to personalize interventions for hearing loss and understand individual differences in intervention outcomes. A pressing methods question is the extent to which the time scale of the sample and number of sampling periods need to be considered. The purpose of this study was to characterize the extent to which the sound levels in a listener's vicinity, one common measure of acoustic environments, change across different time scales.

Revisiting the 40-Hz gamma response: Phase-locked neural activity along the human auditory pathway relates to bilingual experience.

Spoken language experience influences brain responses to sound, but it is unclear whether this neuroplasticity is limited to speech frequencies (>100 Hz) or also affects lower gamma ranges (∼30-60 Hz). Using the frequency-following response (FFR), a far-field phase-locked response to sound, we explore whether bilingualism influences the location of the strongest response in the gamma range. Our results indicate that the strongest gamma response for bilinguals is most often at 43 Hz, compared to 51 Hz for monolinguals.

Western Blot Characterization of Human Serum Prestin, an Outer Hair Cell Biomarker.

Hypothesis: Western blot analysis of human prestin in the blood reveals multiple bands, rather than a single band.

Background: Previously, using the ELISA method, prestin was shown to be a good biomarker of outer hair cell (OHC) health and sensorineural hearing loss that could be measured in the blood. Recently, we found that a Western blot approach in an experimental model demonstrated three prestin bands providing greater insights into prestin in the blood and its origins.

Effects of cultural dynamics on everyday acoustic environmentsa).

Differences in acoustic environments have previously been linked to socioeconomic status (SES). However, it is crucial to acknowledge that cultural values can also play a significant role in shaping acoustic environments. The goal of this study was to investigate if social behaviors related to cultural heritage and SES could help us understand how Latinx and European college students in the U.

Individual differences in the perception of phonetic category structure predict speech-in-noise performance.

Speech sounds exist in a complex acoustic-phonetic space, and listeners vary in the extent to which they are sensitive to variability within the speech sound category ("gradience") and the degree to which they show stable, consistent responses to phonetic stimuli. Here, we investigate the hypothesis that individual differences in the perception of the sound categories of one's language may aid speech-in-noise performance across the adult lifespan. Declines in speech-in-noise performance are well documented in healthy aging, and are, unsurprisingly, associated with differences in hearing ability.

Hypoactivation of the central auditory system in listeners who are hypertolerant of background noise.

Listeners exhibit varying levels of tolerance for background noise during speech communication. It has been proposed that low tolerance of background noise may be the consequence of abnormally amplified gain in the central auditory system (CAS). Here, using a dataset of young adults with normal hearing thresholds, we asked whether central gain mechanisms might also explain cases of hypertolerance of background noise, as well as cases of reduced, but not abnormal, tolerance.

Neural Delays in Processing Speech in Background Noise Minimized after Short-Term Auditory Training.

Background noise disrupts the neural processing of sound, resulting in delayed and diminished far-field auditory-evoked responses. In young adults, we previously provided evidence that cognitively based short-term auditory training can ameliorate the impact of background noise on the frequency-following response (FFR), leading to greater neural synchrony to the speech fundamental frequency(F0) in noisy listening conditions. In this same dataset (55 healthy young adults), we now examine whether training-related changes extend to the latency of the FFR, with the prediction of faster neural timing after training.

Serum Levels of Stereocilin as a Hearing Biomarker.

Noise-induced hearing loss (NIHL) often presents with an insidious onset, resulting from the cumulative effect of chronic, high-level noise exposure regardless of etiology. Stereocilin (STRC) is a protein that supports stereocilia attachment and cochlear hair cell function, 2 common targets of noise trauma. In this study, we explored the relationship between STRC and daily noise exposure in young, healthy adults.

Heightened OAEs in young adult musicians: Influence of current noise exposure and training recency.

Otoacoustic emissions (OAEs) are a non-invasive metric of cochlear function. Studies of OAEs in musicians have yielded mixed results, ranging from evidence of diminished OAEs in musicians-suggesting noise-induced hearing loss-to no difference when compared to non-musicians, or even a trend for stronger OAEs in musicians. The goal of this study was to use a large sample of college students with normal hearing (n = 160) to compare OAE SNRs in musicians and non-musicians and to explore potential effects of training recency and noise exposure on OAEs in these cohorts.

A high-density EEG and structural MRI source analysis of the frequency following response to missing fundamental stimuli reveals subcortical and cortical activation to low and high frequency stimuli.

Pitch is a perceptual rather than physical phenomenon, important for spoken language use, musical communication, and other aspects of everyday life. Auditory stimuli can be designed to probe the relationship between perception and physiological responses to pitch-evoking stimuli. One technique for measuring physiological responses to pitch-evoking stimuli is the frequency following response (FFR).

Cultural differences in auditory ecology.

Demographic differences in acoustic environments are usually studied using geographic area monitoring. This approach, however, may miss valuable information differentiating cultures. This motivated the current study, which used wearable sound recorders to measure noise levels and speech-to-noise ratios (SNRs) in the immediate acoustic environment of Latinx and European-American college students.

Age-related declines to serum prestin levels in humans.

Measurement of the motor protein prestin offers a novel approach to assessing outer hair cell (OHC) status using serological techniques. Motivated by our prior work showing reduced serum prestin levels in healthy young adults at-risk for noise damage, the current study examined serum prestin levels, measured from circulating blood, across the age span from 18 to 82 years old. Results suggest that serum prestin levels negatively correlate with age, with young adults having higher levels of circulating serum in the blood than older adults.

A Home-Based Approach to Auditory Brainstem Response Measurement: Proof-of-Concept and Practical Guidelines.

Broad-scale neuroscientific investigations of diverse human populations are difficult to implement. This is because the primary neuroimaging methods (magnetic resonance imaging, electroencephalography [EEG]) historically have not been portable, and participants may be unable or unwilling to travel to test sites. Miniaturization of EEG technologies has now opened the door to neuroscientific fieldwork, allowing for easier access to under-represented populations.

Evidence for a Musician Speech-Perception-in-Noise Advantage in School-Age Children.

Purpose: The objective of this study was to evaluate whether child musicians are better at listening to speech in noise (SPIN) than nonmusicians of the same age. In addition, we aimed to explore whether the musician SPIN advantage in children was related to general intelligence (IQ).

Method: Fifty-one children aged 8.

Automatic sound encoding is sensitive to language familiarity: Evidence from English monolinguals and Spanish-English bilinguals.

We investigated whether language familiarity has a modulatory effect on automatic sound encoding in the auditory brainstem by measuring frequency-following responses (FFRs) to repeating speech syllables that played in the background while monolingual English speakers and Spanish-English bilingual speakers watched cartoon videos in English and Spanish. For the English monolinguals, we found that the FFR signal quality was different between the two language conditions, with higher signal to noise ratios emerging for the Spanish compared to the English condition. For the Spanish-English bilinguals, the FFR signal quality was overall higher than the monolinguals, but there no effect of language condition on the FFR.

Noise exposure levels predict blood levels of the inner ear protein prestin.

Serological biomarkers of inner ear proteins are a promising new approach for studying human hearing. Here, we focus on the serological measurement of prestin, a protein integral to a human's highly sensitive hearing, expressed in cochlear outer hair cells (OHCs). Building from recent nonhuman studies that associated noise-induced OHC trauma with reduced serum prestin levels, and studies suggesting subclinical hearing damage in humans regularly engaging in noisy activities, we investigated the relation between serum prestin levels and environmental noise levels in young adults with normal clinical audiograms.

Auditory Cortical Changes Precede Brainstem Changes During Rapid Implicit Learning: Evidence From Human EEG.

The auditory system is sensitive to stimulus regularities such as frequently occurring sounds and sound combinations. Evidence of regularity detection can be seen in how neurons across the auditory network, from brainstem to cortex, respond to the statistical properties of the soundscape, and in the rapid learning of recurring patterns in their environment by children and adults. Although rapid auditory learning is presumed to involve functional changes to the auditory network, the chronology and directionality of changes are not well understood.

Auditory Temporal Processing in Dancers.

While many studies have examined the auditory abilities of musicians, this study uniquely asks whether dance training, a similar yet understudied type of early-life training, also benefits auditory abilities. We focused this investigation on temporal resolution, given the importance of subtle temporal cues in synchronizing movement. We found that, compared to untrained controls, novice adult dancers who have trained continuously since childhood had enhanced temporal resolution, measured with a gap detection task.

Reliability of Serological Prestin Levels in Humans and its Relation to Otoacoustic Emissions, a Functional Measure of Outer Hair Cells.

Objectives: Serological biomarkers, common to many areas of medicine, have the potential to inform on the health of the human body and to give early warning of risk of compromised function or illness before symptoms are experienced. Serological measurement of prestin, a motor protein uniquely produced and expressed in outer hair cells, has recently been identified as a potential biomarker to inform on the health of the cochlea. Before any test can be introduced into the clinical toolkit, the reproducibility of the measurement when repeated in the same subject must be considered.

Multi-Voiced Music Bypasses Attentional Limitations in the Brain.

Attentional limits make it difficult to comprehend concurrent speech streams. However, multiple musical streams are processed comparatively easily. Coherence may be a key difference between music and stimuli like speech, which does not rely on the integration of multiple streams for comprehension.

Baseline, retest, and post-injury profiles of auditory neural function in collegiate football players.

Objectives: Recent retrospective studies report differences in auditory neurophysiology between concussed athletes and uninjured controls using the frequency-following response (FFR). Adopting a prospective design in college football players, we compared FFRs before and after a concussion and evaluated test-retest reliability in non-concussed teammates.

Design: Testing took place in a locker room.

Comparisons of Auditory Brainstem Responses Between a Laboratory and Simulated Home Environment.

Purpose Miniaturization of digital technologies has created new opportunities for remote health care and neuroscientific fieldwork. The current study assesses comparisons between in-home auditory brainstem response (ABR) recordings and recordings obtained in a traditional lab setting. Method Click-evoked and speech-evoked ABRs were recorded in 12 normal-hearing, young adult participants over three test sessions in (a) a shielded sound booth within a research lab, (b) a simulated home environment, and (c) the research lab once more.

Phonetic discrimination mediates the relationship between auditory brainstem response stability and syntactic performance.

Syntactic, lexical, and phonological/phonetic knowledge are vital aspects of macro level language ability. Prior research has predominantly focused on environmental or cortical sources of individual differences in these areas; however, a growing literature suggests an auditory brainstem contribution to language performance in both typically developing (TD) populations and children with autism spectrum disorder (ASD). This study investigates whether one aspect of auditory brainstem responses (ABRs), neural response stability, which is a metric reflecting trial-by-trial consistency in the neural encoding of sound, can predict syntactic, lexical, and phonetic performance in TD and ASD school-aged children.

Evolving perspectives on the sources of the frequency-following response.

The auditory frequency-following response (FFR) is a non-invasive index of the fidelity of sound encoding in the brain, and is used to study the integrity, plasticity, and behavioral relevance of the neural encoding of sound. In this Perspective, we review recent evidence suggesting that, in humans, the FFR arises from multiple cortical and subcortical sources, not just subcortically as previously believed, and we illustrate how the FFR to complex sounds can enhance the wider field of auditory neuroscience. Far from being of use only to study basic auditory processes, the FFR is an uncommonly multifaceted response yielding a wealth of information, with much yet to be tapped.