The impoverished brain: disparities in maternal education affect the neural response to sound

Uneven Impact of Maternal Education at Birth on High School Grades of Black and White Students

Background

The Minorities' Diminished Returns (MDRs) theory posits that social determinants of health, such as parental education, exert weaker protective effects on health and educational outcomes in racialized and minoritized populations compared to White populations.

Aim

This study examines whether higher maternal education is associated with better high school GPA in Black youth and whether this association aligns with the MDRs framework.

Methods

Data were drawn from the Future of Families and Child Wellbeing Study also known as Fragile Families and Child Wellbeing Study (FFCWS) baseline and 22nd year follow-up (1990-2022). This study included 1873 Black or White participants who were followed from birth to age 22. Linear regression models were used to assess the association between maternal education and high school GPA, adjusting for sociodemographic covariates. Analyses focused on the differential effects of maternal education across racial groups, particularly among Black youth.

Results

While maternal education was positively associated with high school GPA, this effect was weaker for Black students compared to their White counterparts. Specifically, each additional year of maternal education corresponded to a lower GPA increase in Black students, consistent with the MDRs hypothesis.

Conclusion

Findings support the MDRs theory, indicating that maternal education has a reduced protective effect on high school GPA among Black youth. These results underscore the need for policies that address structural factors beyond education to promote equitable academic achievement.

Individual differences in the consistency of neural and behavioural responses to speech sounds

There are documented individual differences among adults in the consistency of speech sound processing, both at neural and behavioural levels. Some adults show more consistent neural responses to speech sounds than others, as measured by an event-related potential called the frequency-following response (FFR); similarly, some adults show more consistent behavioural responses to native speech sounds than others, as measured by two-alternative forced choice (2AFC) and visual analog scaling (VAS) tasks. Adults also differ in how successfully they can perceive non-native speech sounds. Interestingly, it remains unclear whether these differences are related within individuals. In the current study, native English-speaking adults completed native phonetic perception tasks (2AFC and VAS), a non-native (German) phonetic perception task, and an FFR recording session. From these tasks, we derived measures of the consistency of participants' neural and behavioural responses to native speech as well as their non-native perception ability. We then examined the relationships among individual differences in these measures. Analysis of the behavioural measures revealed that more consistent responses to native sounds predicted more successful perception of unfamiliar German sounds. Analysis of neural and behavioural data did not reveal clear relationships between FFR consistency and our phonetic perception measures. This multimodal work furthers our understanding of individual differences in speech processing among adults, and may eventually lead to individualized approaches for enhancing non-native language acquisition in adulthood.

Relationship Between Socioeconomic Status and Basic Auditory Processing in Young Adults

PURPOSE

The current study aimed at investigating the relationship between socioeconomic status (SES) and basic auditory processing in young adults with normal hearing. Specifically, we sought to determine whether SES metrics, including parental education, parental occupation, and individual education attainment, influenced performance on tasks of basic auditory processing. Secondarily, we also aimed at understanding the interactive effects of SES and working memory on basic auditory processing.

METHOD

A total of 38 young adults were included in the study. Self-reported SES measures were recorded through Likert scales, and auditory processing measures included tests for temporal fine structure (TFS) and spectrotemporal sensitivity (STS). Pearson correlation analyses were conducted to probe the relationships between SES indicators and auditory processing performance. Multiple linear regressions were conducted to understand the interactive effects of SES and working memory on auditory processing performance.

RESULTS

The analysis revealed no significant correlation between SES measures and basic auditory processing performance across TFS and STS tasks. Furthermore, analysis investigating the interaction between SES and working memory also yielded nonsignificant results. These findings indicate that, within this specific age cohort, SES information may not be indispensable for assessing basic auditory processing.

CONCLUSIONS

Our study suggests that SES may not significantly influence basic auditory processing in young adults with normal hearing. However, further research with larger sample sizes and longitudinal designs is warranted to confirm these findings and explore potential age-related differences in the impact of SES on auditory processing across the lifespan.

Childhood Listening and Associated Cognitive Difficulties Persist Into Adolescence

OBJECTIVE

Listening difficulty (LiD) refers to the challenges individuals face when trying to hear and comprehend speech and other sounds. LiD can arise from various sources, such as hearing sensitivity, language comprehension, cognitive function, or auditory processing. Although some children with LiD have hearing loss, many have clinically normal audiometric thresholds. To determine the impact of hearing and cognitive factors on LiD in children with a clinically normal audiogram, we conducted a longitudinal study. The Evaluation of Children's Listening & Processing Skills (ECLiPS), a validated and standardized caregiver evaluation tool, was used to group participants as either LiD or typically developing (TD). Our previous study aimed to characterize LiD in 6- to 13-year-old children during the project's baseline, cross-sectional phase. We found that children with LiD needed a higher signal-to-noise ratio during speech-in-speech tests and scored lower on all assessed components of the NIH Cognition Toolbox than TD children. The primary goal of this study was to examine if the differences between LiD and TD groups are temporary or enduring throughout childhood.

DESIGN

This longitudinal study had three data collection waves for children with LiD and TD aged 6 to 13 years at Wave 1, followed by assessments at 2-year (Wave 2) and 4-year (Wave 3) intervals. Primary analysis focused on data from Waves 1 and 2. Secondary analysis encompassed all three waves despite high attrition at Wave 3. Caregivers completed the ECLiPS, while participants completed the Listening in Spatialized Noise-Sentences (LiSN-S) test and the NIH-Toolbox Cognition Battery during each wave. The analysis consisted of (1) examining longitudinal differences between TD and LiD groups in demographics, listening, auditory, and cognitive function; (2) identifying functional domains contributing to LiD; and (3) test-retest reliability of measures across waves. Mixed-effect models were employed to analyze longitudinal data.

RESULTS

The study enrolled 169 participants, with 147, 100, and 31 children completing the required testing during Waves 1, 2, and 3, respectively. The mean ages at these waves were 9.5, 12.0, and 14.0 years. On average, children with LiD consistently underperformed TD children in auditory and cognitive tasks across all waves. Maternal education, auditory, and cognitive abilities independently predicted caregiver-reported listening skills. Significant correlations between Waves 1 and 2 confirmed high, long-term reliability. Secondary analysis of Wave 3 was consistent with the primary analyses of Waves 1 and 2, reinforcing the enduring nature of listening difficulties.

CONCLUSION

Children with LiD and clinically normal audiograms experience persistent auditory, listening, and cognitive challenges through at least adolescence. The degree of LiD can be independently predicted by maternal education, cognitive processing, and spatial listening skills. This study underscores the importance of early detection and intervention for childhood LiD and highlights the role of socioeconomic factors as contributors to these challenges.

Auditory Neural Responses and Communicative Functioning in Children With Microcephaly Related to Congenital Zika Syndrome

OBJECTIVES

Children with microcephaly exhibit neurodevelopmental delays and compromised communicative functioning, yielding challenges for clinical assessment and informed intervention. This study characterized auditory neural function and communication abilities in children with microcephaly due to congenital Zika syndrome (CZS).

DESIGN

Click-evoked auditory brainstem responses (ABR) at fast and slow stimulation rates and natural speech-evoked cortical auditory evoked potentials (CAEP) were recorded in 25 Brazilian children with microcephaly related to CZS ( M age: 5.93 ± 0.62 years) and a comparison group of 25 healthy children ( M age: 5.59 ± 0.80 years) matched on age, sex, ethnicity, and socioeconomic status. Communication abilities in daily life were evaluated using caregiver reports on Vineland Adaptive Behavior Scales-3.

RESULTS

Caregivers of children with microcephaly reported significantly lower than typical adaptive functioning in the communication and socialization domains. ABR wave I latency did not differ significantly between the groups, suggesting comparable peripheral auditory function. ABR wave V absolute latency and waves I-V interwave latency were significantly shorter in the microcephaly group for both ears and rates. CAEP analyses identified reduced N2 amplitudes in children with microcephaly as well as limited evidence of speech sound differentiation, evidenced mainly by the N2 response latency. Conversely, in the comparison group, speech sound differences were observed for both the P1 and N2 latencies. Exploratory analyses in the microcephaly group indicated that more adaptive communication was associated with greater speech sound differences in the P1 and N2 amplitudes. The trimester of virus exposure did not have an effect on the ABRs or CAEPs.

CONCLUSIONS

Microcephaly related to CZS is associated with alterations in subcortical and cortical auditory neural function. Reduced ABR latencies differ from previous reports, possibly due to the older age of this cohort and careful assessment of peripheral auditory function. Cortical speech sound detection and differentiation are present but reduced in children with microcephaly. Associations between communication performance in daily life and CAEPs highlight the value of auditory evoked potentials in assessing clinical populations with significant neurodevelopmental disabilities.

Social interactions offset the detrimental effects of digital media use on children's vocabulary

Young children's rapid vocabulary growth during the first few years is supported by input during social interactions with caregivers and, increasingly, from digital media. However, the amount of exposure to both sources can vary substantially across socioeconomic classes, and little is known about how social interactions and digital media use together predict vocabulary in the first few years of life. The current study takes a first step toward examining whether increased social interactions with other individuals may buffer the potentially detrimental effects of digital media use on language among a socioeconomically diverse sample. 305 caregivers of children between 17 and 30-months completed questionnaires about their family demographics, their child's technology use, and the child's daily routines and social interactions. Findings suggest children who experience fewer human interactions and greater technology exposure have smaller vocabularies than their peers who socialize more and use less technology, and this disparity becomes greater as children get older. Moreover, the number of social interactions moderates the link between SES, digital media, and vocabulary such that the negative impact of digital media on vocabulary for children from low SES households can be offset with increased social interactions. Together, this suggests that increasing the amount of human interactions may serve as a protective factor for vocabulary outcomes in a world where digital media use is prominent.

Neural Mechanisms of Nonauditory Effects of Noise Exposure on Special Populations

Due to the abnormal structure and function of brain neural networks in special populations, such as children, elderly individuals, and individuals with mental disorders, noise exposure is more likely to have negative psychological and cognitive nonauditory effects on these individuals. There are unique and complex neural mechanisms underlying this phenomenon. For individuals with mental disorders, there are anomalies such as structural atrophy and decreased functional activation in brain regions involved in emotion and cognitive processing, such as the prefrontal cortex (PFC). Noise exposure can worsen these abnormalities in relevant brain regions, further damaging neural plasticity and disrupting normal connections and the transmission of information between the PFC and other brain areas by causing neurotransmitter imbalances. In the case of children, in a noisy environment, brain regions such as the left inferior frontal gyrus and PFC, which are involved in growth and development, are more susceptible to structural and functional changes, leading to neurodegenerative alterations. Furthermore, noise exposure can interrupt auditory processing neural pathways or impair inhibitory functions, thus hindering children's ability to map sound to meaning in neural processes. For elderly people, age-related shrinkage of brain regions such as the PFC, as well as deficiencies in hormone, neurotransmitter, and nutrient levels, weakens their ability to cope with noise. Currently, it is feasible to propose and apply coping strategies to improve the nonauditory effects of noise exposure on special populations based on the plasticity of the human brain.

A systematic review of interventions to ameliorate the impact of adversity on brain development

Adversity, including abuse, neglect, and poverty, impacts child brain development. However, the developing brain is highly plastic, and some of the impacts of childhood adversity may be mitigated by psychosocial interventions. The purpose of this review is to synthesize literature on neural outcomes of childhood interventions among individuals exposed to adversity. A systematic literature search identified 36 reports of 13 interventions. Overall, these studies provide evidence for experience-dependent plasticity in the developing brain. We synthesize studies in light of three themes. First, there was mixed evidence for a benefit of a younger age at intervention. Second, interventions tended to accelerate functional brain development, but the impact of interventions on the pace of structural brain development was less clear. Third, individual differences in intervention response were difficult to predict, in part due to small samples. However, there was significant variability in intervention type and timing, neuroimaging outcomes, and follow-up timing. Together, the studies reviewed here hold promise for the role of psychosocial interventions in ameliorating the neurodevelopmental consequences of childhood adversity.

Neural Processing of Speech Sounds in ASD and First-Degree Relatives

Efficient neural encoding of sound plays a critical role in speech and language, and when impaired, may have reverberating effects on communication skills. This study investigated disruptions to neural processing of temporal and spectral properties of speech in individuals with ASD and their parents and found evidence of inefficient temporal encoding of speech sounds in both groups. The ASD group further demonstrated less robust neural representation of spectral properties of speech sounds. Associations between neural processing of speech sounds and language-related abilities were evident in both groups. Parent-child associations were also detected in neural pitch processing. Together, results suggest that atypical neural processing of speech sounds is a heritable ingredient contributing to the ASD language phenotype.

Early-life stress affects Mongolian gerbil interactions with conspecific vocalizations in a sex-specific manner

During development, early-life stress (ELS) impairs cognition, learning, and emotional regulation, in part by disrupting neural circuitry in regions underlying these higher-order functions. In addition, our recent work indicates that ELS also alters simple sensory perception: ELS impaired auditory perception and neural encoding of short gaps in sounds, which are essential for vocal communication. The combination of higher-order and basic sensory disruption suggests that ELS is likely to affect both the perception and interpretation of communication signals. We tested this hypothesis by measuring behavioral responses to conspecific vocalizations (those emitted by other gerbils) in ELS and untreated Mongolian gerbils. Because stress effects often differ by sex, we separately examined females and males. To induce ELS, pups were intermittently maternally separated and restrained from post-natal days (P) 9-24, a time window when the auditory cortex is most sensitive to external disruption. We measured the approach responses of juvenile (P31-32) gerbils to two types of conspecific vocalizations: an alarm call, which is emitted to alert other gerbils of a potential threat, and the prosocial contact call, which is emitted near familiar gerbils, especially after separation. Control males, Control females, and ELS females approached a speaker emitting pre-recorded alarm calls, while ELS males avoided this source, suggesting that ELS affects the response to alarm calls in male gerbils. During playback of the pre-recorded contact call, Control females and ELS males avoided the sound source, while Control males neither approached nor avoided, and ELS females approached the sound. These differences cannot be accounted for by changes in locomotion or baseline arousal. However, ELS gerbils slept more during playback, suggesting that ELS may reduce arousal during vocalization playback. Further, male gerbils made more errors than females on a measure of working memory, but the sex difference of cognition in this context may stem from novelty aversion rather than impaired memory. These data indicate that ELS influences behavioral responses to ethologically relevant communication sounds in a sex-specific manner, and are among the first to demonstrate an altered response to auditory stimuli following ELS. Such changes may arise from differences in auditory perception, cognition, or a combination of factors, and suggest that ELS may affect auditory communication in human adolescents.

Early-Life Stress Impairs Perception and Neural Encoding of Rapid Signals in the Auditory Pathway

During developmental critical periods (CPs), early-life stress (ELS) induces cognitive deficits and alters neural circuitry in regions underlying learning, memory, and attention. Mechanisms underlying critical period plasticity are shared by sensory cortices and these higher neural regions, suggesting that sensory processing may also be vulnerable to ELS. In particular, the perception and auditory cortical (ACx) encoding of temporally-varying sounds both mature gradually, even into adolescence, providing an extended postnatal window of susceptibility. To examine the effects of ELS on temporal processing, we developed a model of ELS in the Mongolian gerbil, a well-established model for auditory processing. In both male and female animals, ELS induction impaired the behavioral detection of short gaps in sound, which are critical for speech perception. This was accompanied by reduced neural responses to gaps in auditory cortex, the auditory periphery, and auditory brainstem. ELS thus degrades the fidelity of sensory representations available to higher regions, and could contribute to well-known ELS-induced problems with cognition.SIGNIFICANCE STATEMENT In children and animal models, early-life stress (ELS) leads to deficits in cognition, including problems with learning, memory, and attention. Such problems could arise in part from a low-fidelity representation of sensory information available to higher-level neural regions. Here, we demonstrate that ELS degrades sensory responses to rapid variations in sound at multiple levels of the auditory pathway, and concurrently impairs perception of these rapidly-varying sounds. As these sound variations are intrinsic to speech, ELS may thus pose a challenge to communication and cognition through impaired sensory encoding.

Maternal Education Potentially Moderates the MAOA uVNTR Effects on Externalizing Behavior in Black South African Children

Interactions between the MAOA uVNTR and rearing environment are suggested to influence the developmental manifestations of childhood internalizing and externalizing behavior. However, few studies in the MAOA literature have included continental African children, or focused on non-clinical samples. We explored the main and interactive effects of the MAOA uVNTR (high and low activity alleles) in Black South African male (n = 478) and female (n = 540) children who were part of the longitudinal Birth to Twenty Plus cohort. Historical data on birth weight, gestational age at delivery, socioeconomic status, and maternal education were combined with genotypic information and analyzed using regression modeling. We found no significant main effects for the MAOA uVNTR on childhood behavior in either sex. A significant interaction (p = .04) was identified between MAOA and maternal education, suggesting that externalizing behavior in boys carrying a low activity MAOA allele varied in direct proportion to the education levels of their mothers. However, the model fit failed to reach significance, possibly due to our inclusion of only non-clinical pre-pubertal males. No significant interactions were detected for female children. Our findings lend tentative credibility to the Environmental Sensitivity metaframework, which suggests that MAOA is an important plasticity factor in childhood development.

Speech Error Variability and Phonological Awareness in Preschoolers

PURPOSE

The purpose of this article was to investigate the relationship between speech error variability and phonological awareness.

METHOD

This article begins with a narrative review of the theoretical interpretation of speech error variability. The post hoc exploratory analysis of the relationship between speech error variability and phonological awareness included 40 children: 20 with typical speech and language and 20 with speech sound disorder and typical language. Groups were matched on gender, age, maternal education, receptive and expressive vocabulary, nonverbal intelligence, and expressive morphosyntax. Multiple regression was used to identify the best fit model for the relationship between vocabulary, speech errors, and phonological awareness.

RESULTS

Segmental variability was associated with poor phonological awareness in preschool-aged children.

CONCLUSION

Children with high levels of segmental variability have poor phonological awareness, likely due to unstable phonological representations.

Immigration Status, Socioeconomic Status, and Self-Rated Health in Europe

The literature has established a protective effect of socioeconomic status (SES) indicators on health. However, at least in the US, these SES indicators tend to generate fewer health gains for marginalized groups including immigrants. As this literature mainly originated in the US, it is necessary to study whether these indicators similarly correlate with the health of foreign-born and native-born individuals in Europe. The current study was based on the Marginalization-related Diminished Returns (MDRs) theory and compared the effects of three SES indicators, namely parental education, own education and income, on self-rated health (SRH) of immigrant and native-born individuals. We used data from the European Social Survey 2020 (ESS 2020). Participants included 14,213 individuals who identified as either native-born (n = 9052) or foreign-born (n = 508). Education, income, and parental education were the independent variables. Self-rated health (SRH) was the outcome. Age and sex were covariates. Linear regression and logistic regression were used for data analysis. Overall, high education, income, and parental education were associated with lower odds of poor SRH. We documented a statistical interaction between immigration status and parental education, indicating a weaker inverse association between parental education and poor SRH for foreign-born than native-born individuals. The links between some but not all SES indicators vary across foreign-born and native-born individuals in Europe. Host countries seem to undervalue the parental educational attainment of foreign-born families. Future research should explore the role of time, period, cohort and country of origin as well as host country and associated policies in equalizing returns of SES indicators on the health of population subgroups. The results are important given that most studies on MDRs are developed in the US, and less is known about Europe. The results are also very important given the growing anti-immigrant sentiment and nationalist movements in Europe and the rest of the world.

Athleticism and sex impact neural processing of sound

Biology and experience both influence the auditory brain. Sex is one biological factor with pervasive effects on auditory processing. Females process sounds faster and more robustly than males. These differences are linked to hormone differences between the sexes. Athleticism is an experiential factor known to reduce ongoing neural noise, but whether it influences how sounds are processed by the brain is unknown. Furthermore, it is unknown whether sports participation influences auditory processing differently in males and females, given the well-documented sex differences in auditory processing seen in the general population. We hypothesized that athleticism enhances auditory processing and that these enhancements are greater in females. To test these hypotheses, we measured auditory processing in collegiate Division I male and female student-athletes and their non-athlete peers (total n = 1012) using the frequency-following response (FFR). The FFR is a neurophysiological response to sound that reflects the processing of discrete sound features. We measured across-trial consistency of the response in addition to fundamental frequency (F0) and harmonic encoding. We found that athletes had enhanced encoding of the harmonics, which was greatest in the female athletes, and that athletes had more consistent responses than non-athletes. In contrast, F0 encoding was reduced in athletes. The harmonic-encoding advantage in female athletes aligns with previous work linking harmonic encoding strength to female hormone levels and studies showing estrogen as mediating athlete sex differences in other sensory domains. Lastly, persistent deficits in auditory processing from previous concussive and repetitive subconcussive head trauma may underlie the reduced F0 encoding in athletes, as poor F0 encoding is a hallmark of concussion injury.

Reconsidering commonly used stimuli in speech perception experiments

This paper examines some commonly used stimuli in speech perception experiments and raises questions about their use, or about the interpretations of previous results. The takeaway messages are: 1) the Hillenbrand vowels represent a particular dialect rather than a gold standard, and English vowels contain spectral dynamics that have been largely underappreciated, 2) the /ɑ/ context is very common but not clearly superior as a context for testing consonant perception, 3) /ɑ/ is particularly problematic when testing voice-onset-time perception because it introduces strong confounds in the formant transitions, 4) /dɑ/ is grossly overrepresented in neurophysiological studies and yet is insufficient as a generalized proxy for "speech perception," and 5) digit tests and matrix sentences including the coordinate response measure are systematically insensitive to important patterns in speech perception. Each of these stimulus sets and concepts is described with careful attention to their unique value and also cases where they might be misunderstood or over-interpreted.

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. Recent efforts to conduct auditory neuroscience outside a laboratory setting are reviewed and then an in-home technique for recording auditory brainstem responses (ABRs) and frequency-following responses (FFRs) in a home setting is introduced. As a proof of concept, we have conducted two in-home electrophysiological studies: one in 27 children aged 6 to 16 years (13 with autism spectrum disorder) and another in 12 young adults aged 18 to 27 years, using portable electrophysiological equipment to record ABRs and FFRs to click and speech stimuli, spanning rural and urban and multiple homes and testers. We validate our fieldwork approach by presenting waveforms and data on latencies and signal-to-noise ratio. Our findings demonstrate the feasibility and utility of home-based ABR/FFR techniques, paving the course for larger fieldwork investigations of populations that are difficult to test or recruit. We conclude this tutorial with practical tips and guidelines for recording ABRs and FFRs in the field and discuss possible clinical and research applications of this approach.

Environmental noise, brain structure, and language development in children

While excessive noise exposure in childhood has been associated with reduced language ability, few studies have examined potential underlying neurobiological mechanisms that may account for noise-related differences in language skills. In this study, we tested the hypotheses that higher everyday noise exposure would be associated with 1) poorer language skills and 2) differences in language-related cortical structure. A socioeconomically diverse sample of children aged 5-9 (N = 94) completed standardized language assessments. High-resolution T1-weighted magnetic resonance imaging (MRI) scans were acquired, and surface area and cortical thickness of the left inferior frontal gyrus (IFG) and left superior temporal gyrus (STG) were extracted. Language Environmental Analysis (LENA) was used to measure levels of exposure to excessive environmental noise over the course of a typical day (n = 43 with complete LENA, MRI, and behavioral data). Results indicated that children exposed to excessive levels of noise exhibited reduced cortical thickness in the left IFG. These findings add to a growing literature that explores the extent to which home environmental factors, such as environmental noise, are associated with neurobiological development related to language development in children.

Vowel errors produced by preschool-age children on a single-word test of articulation

Eighty-four children, age 4-5 years, with and without speech sound disorder (SSD) completed a battery of standardized speech and language tests, including the Goldman-Fristoe Test of Articulation, Third Edition (GFTA-3). Children with SSD produced more vowel errors than children with typical speech abilities. Percentage vowels correct and consonant error variability were highly correlated, suggesting that poorly specified phonological representations affect both consonants and vowels within a child's phonological system. However, the GFTA-3 did not contain sufficient target words to determine full vowel inventory. Using words from the GFTA-3, we present a case study of a child with vowel errors along with a sample analysis of these errors, primarily in terms of consonant-vowel feature interactions. Children who exhibit vowel errors on standardized single-word tests of speech accuracy may benefit from further vowel probes to determine how vowel and consonant errors interact in their phonological systems for more targeted therapy.

Non-stimulus-evoked activity as a measure of neural noise in the frequency-following response

BACKGROUND

The frequency-following response, or FFR, is a neurophysiologic response that captures distinct aspects of sound processing. Like all evoked responses, FFR is susceptible to electric and myogenic noise contamination during collection. Click-evoked auditory brainstem response collection standards have been adopted for FFR collection, however, whether these standards sufficiently limit FFR noise contamination is unknown. Thus, a critical question remains: to what extent do distinct FFR components reflect noise contamination? This is especially relevant for prestimulus amplitude (i.e., activity preceding the evoked response), as this measure has been used to index both noise contamination and neural noise.

NEW METHOD

We performed two experiments. First, using >1000 young-adult FFRs, we ran regressions to determine the variance explained by myogenic and electrical noise, as indexed by artifact rejection count and electrode impedance, on each FFR component. Second, we reanalyzed prestimulus amplitude differences attributed to athletic experience and socioeconomic status, adding covariates of artifact rejection and impedance.

RESULTS

We found that non-neural noise marginally contributed to FFR components and could not explain group differences on prestimulus amplitude.

COMPARISON WITH EXISTING METHOD

Prestimulus amplitude has been considered a measure of non-neural noise contamination. However, non-neural noise was not the sole contributor to variance in this measure and did not explain group differences.

CONCLUSIONS

Results from the two experiments suggest that the effects of non-neural noise on FFR components are minimal and do not obscure individual differences in the FFR and that prestimulus amplitude indexes neural noise.

Auditory neurophysiological development in early childhood: A growth curve modeling approach

OBJECTIVE

During early childhood, the development of communication skills, such as language and speech perception, relies in part on auditory system maturation. Because auditory behavioral tests engage cognition, mapping auditory maturation in the absence of cognitive influence remains a challenge. Furthermore, longitudinal investigations that capture auditory maturation within and between individuals in this age group are scarce. The goal of this study is to longitudinally measure auditory system maturation in early childhood using an objective approach.

METHODS

We collected frequency-following responses (FFR) to speech in 175 children, ages 3-8 years, annually for up to five years. The FFR is an objective measure of sound encoding that predominantly reflects auditory midbrain activity. Eliciting FFRs to speech provides rich details of various aspects of sound processing, namely, neural timing, spectral coding, and response stability. We used growth curve modeling to answer three questions: 1) does sound encoding change across childhood? 2) are there individual differences in sound encoding? and 3) are there individual differences in the development of sound encoding?

RESULTS

Subcortical auditory maturation develops linearly from 3-8 years. With age, FFRs became faster, more robust, and more consistent. Individual differences were evident in each aspect of sound processing, while individual differences in rates of change were observed for spectral coding alone.

CONCLUSIONS

By using an objective measure and a longitudinal approach, these results suggest subcortical auditory development continues throughout childhood, and that different facets of auditory processing follow distinct developmental trajectories.

SIGNIFICANCE

The present findings improve our understanding of auditory system development in typically-developing children, opening the door for future investigations of disordered sound processing in clinical populations.

The Relationship Between Socioeconomic Status and Scalp Event-Related Potentials: A Systematic Review

Several decades of behavioral research have established that variations in socioeconomic status (SES) are related to differences in cognitive performance. Neuroimaging and psychophysiological techniques have recently emerged as a method of choice to better understand the neurobiological processes underlying this phenomenon. Here we present a systematic review of a particular sub-domain of this field. Specifically, we used the PICOS approach to review studies investigating potential relationships between SES and scalp event-related brain potentials (ERP). This review found evidence that SES is related to amplitude variations in a diverse range of ERPs: P1, N1, N2, Error-Related Negativities (ERN), N400, auditory evoked potentials, negative difference waves (Nd), P3 and slow waves (SW). These ERPs include early, mid-latency and late potentials that reflect a broad range of cognitive processes (e.g., automatic attentional processes, overt attention, language, executive function, etc.). In this review, all SES effects on ERPs appeared to reflect an impairment or a less efficient form of task-related neural activity for low-SES compared to high-SES individuals. Overall, these results confirm that a wide variety of distinct neural processes with different functional meanings are sensitive to SES differences. The findings of this review also suggest that the relationship between SES and some ERP components may depend on the developmental stage of study participants. Results are further discussed in terms of the current limitations of this field and future avenues of research.

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. We analysed the FFR to the fundamental frequency (F0) (FFR-F0) of a speech stimulus, previously identified as a potential concussion biomarker. Baseline FFRs were obtained during the football pre-season. In athletes diagnosed with concussions during the season, FFRs were measured days after injury and compared to pre-season baseline. In uninjured controls, comparisons were made between pre- and post-season.

STUDY SAMPLE

Participants were Tulane University football athletes (n = 65).

RESULTS

In concussed athletes, there was a significant group-level decrease in FFR-F0 from baseline (26% decrease on average). By contrast, the control group's change from baseline was not statistically significant, and comparisons of pre- and post-season had good repeatability (intraclass correlation coefficient = 0.75).

CONCLUSIONS

Results converge with previous work to evince suppressed neural function to the FFR-F0 following concussion. This preliminary study paves the way for larger-scale clinical evaluation of the specificity and reliability of the FFR as a concussion diagnostic.HighlightsThis prospective study reveals suppressed neural responses to sound in concussed athletes compared to baseline.Neural responses to sound show good repeatability in uninjured athletes tested in a locker-room setting.Results support the feasibility of recording frequency-following responses in non-laboratory conditions.

Lifelong Tone Language Experience does not Eliminate Deficits in Neural Encoding of Pitch in Autism Spectrum Disorder

Atypical pitch processing is a feature of Autism Spectrum Disorder (ASD), which affects non-tone language speakers' communication. Lifelong auditory experience has been demonstrated to modify genetically-predisposed risks for pitch processing. We examined individuals with ASD to test the hypothesis that lifelong auditory experience in tone language may eliminate impaired pitch processing in ASD. We examined children's and adults' Frequency-following Response (FFR), a neurophysiological component indexing early neural sensory encoding of pitch. Univariate and machine-learning-based analytics suggest less robust pitch encoding and diminished pitch distinctions in the FFR from individuals with ASD. Contrary to our hypothesis, results point to a linguistic pitch encoding impairment associated with ASD that may not be eliminated even by lifelong sensory experience.

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. Pooling across children with ASD and TD, results showed that higher neural stability in response to the syllable /da/ was associated with better phonetic discrimination, and with better syntactic performance on a standardized measure. Furthermore, phonetic discrimination was a successful mediator of the relationship between neural stability and syntactic performance. This study supports the growing body of literature that stable subcortical neural encoding of sound is important for successful language performance.

Baseline profiles of auditory, vestibular, and visual functions in youth tackle football players

Aim

Neurosensory tests have emerged as components of sport-related concussion management. Limited normative data are available in healthy, nonconcussed youth athletes.

Patients & methods/results

In 2017 and 2018, we tested 108 youth tackle football players immediately before their seasons on the frequency-following response, Balance Error Scoring System, and King-Devick test. We compared results with published data in older and/or and nonathlete populations. Performance on all tests improved with age. Frequency-following response and Balance Error Scoring System results aligned with socioeconomic status. Performance was not correlated across neurosensory domains.

Conclusion

Baseline neurosensory functions in seven 14-year-old male tackle football players are consistent with previously published data. Results reinforce the need for individual baselines or demographic-specific norms and the use of multiple neurosensory measures in sport-related concussion management.

Play Sports for a Quieter Brain: Evidence From Division I Collegiate Athletes

BACKGROUND

Playing sports has many benefits, including boosting physical, cardiovascular, and mental fitness. We tested whether athletic benefits extend to sensory processing-specifically auditory processing-as measured by the frequency-following response (FFR), a scalp-recorded electrophysiological potential that captures neural activity predominately from the auditory midbrain to complex sounds.

HYPOTHESIS

Given that FFR amplitude is sensitive to experience, with enrichment enhancing FFRs and injury reducing them, we hypothesized that playing sports is a form of enrichment that results in greater FFR amplitude.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

We measured FFRs to the speech syllable "da" in 495 student-athletes across 19 Division I teams and 493 age- and sex-matched controls and compared them on 3 measures of FFR amplitude: amplitude of the response, amplitude of the background noise, and the ratio of these 2 measures.

RESULTS

Athletes have larger responses to sound than nonathletes, driven by a reduction in their level of background neural noise.

CONCLUSION

These findings suggest that playing sports increases the gain of an auditory signal by turning down the background noise. This mode of enhancement may be tied to the overall fitness level of athletes and/or the heightened need of an athlete to engage with and respond to auditory stimuli during competition.

CLINICAL RELEVANCE

These results motivate athletics overall and engagement in athletic interventions for populations that struggle with sensory processing, such as individuals with language disorders. Also, because head injuries can disrupt these same auditory processes, it is important to consider how auditory processing enhancements may offset injury.

Analyzing the FFR: A tutorial for decoding the richness of auditory function

The frequency-following response, or FFR, is a neurophysiological response to sound that precisely reflects the ongoing dynamics of sound. It can be used to study the integrity and malleability of neural encoding of sound across the lifespan. Sound processing in the brain can be impaired with pathology and enhanced through expertise. The FFR can index linguistic deprivation, autism, concussion, and reading impairment, and can reflect the impact of enrichment with short-term training, bilingualism, and musicianship. Because of this vast potential, interest in the FFR has grown considerably in the decade since our first tutorial. Despite its widespread adoption, there remains a gap in the current knowledge of its analytical potential. This tutorial aims to bridge this gap. Using recording methods we have employed for the last 20 + years, we have explored many analysis strategies. In this tutorial, we review what we have learned and what we think constitutes the most effective ways of capturing what the FFR can tell us. The tutorial covers FFR components (timing, fundamental frequency, harmonics) and factors that influence FFR (stimulus polarity, response averaging, and stimulus presentation/recording jitter). The spotlight is on FFR analyses, including ways to analyze FFR timing (peaks, autocorrelation, phase consistency, cross-phaseogram), magnitude (RMS, SNR, FFT), and fidelity (stimulus-response correlations, response-to-response correlations and response consistency). The wealth of information contained within an FFR recording brings us closer to understanding how the brain reconstructs our sonic world.

Brain lateralization of phonological awareness varies by maternal education

Socioeconomic status (SES) has been shown to influence language skills, with children of lower SES backgrounds performing worse on language assessments compared to their higher SES peers. While there is abundant behavioral research on the effects of SES, whether there are differences in the neural mechanisms used to support language skill is less established. In this study, we examined the relation between maternal education (ME), a component of SES, and neural mechanisms of language. We focused on Kindergarten children, at the beginning of formal reading education, and on a pre-reading skill, phonological awareness-the ability to distinguish or manipulate the sounds of language. We determined ME-related differences in neural activity by examining a skill-matched sample of typically achieving 5-year-old children as they performed a rhyme judgment task. We examined brain lateralization in two language processing regions, the inferior frontal gyrus (IFG) and superior temporal gyrus (STG). In the IFG, lateralization was related to ME but not skill: children with low ME showed bilateral activation compared to children with higher ME who showed leftward lateralization. In the STG, there was a skill by ME interaction on lateralization, such that children with high ME showed a positive relation between rightward lateralization and skill and children with low ME showed a positive relation between leftward lateralization and skill. Thus, we demonstrated ME is related to differences in neural recruitment during language processing, yet this difference in recruitment is not indicative of a deficit in linguistic processing in Kindergarten children.

Influence of the socieconomic level on the temporal resolution hearing skills in adults

ABSTRACT Objective: to investigate the influence of the socioeconomic level on the temporal resolution auditory ability of adults. Methods: the sample consisted of 48 subjects aged 18 to 50 years, divided into three groups: G1, 11 subjects at level A; G2, 19 in B1 and B2 and G3, 18 in C1, C2, D and E. All subjects presented responses in 20 dB HL in frequencies of 500 to 4000 Hz, during audiometric screening, type A tympanometry, presence of contralateral and ipsilateral acoustic reflexes, no neurological, psychiatric and / or psychological changes diagnosed; without audiological and / or otological complaints and with performance above 95% in the dichotic digit test. The Random Gap Detection and Gap-in-noise tests were performed. The Shapiro-Wilk test for normality analysis and the Kruskall Wallis test for socioeconomic stratum analysis, were used, both with 5% significance. Results: there were statistically significant differences between the groups in the Random Gap Detection in the frequency of 500 Hz and in the average of the frequencies, as a function of the socioeconomic level, the same not being observed in the Gap-in-noise. Conclusions: it is suggested that the socioeconomic level be taken into account in the analysis of the Random Gap Detection test.

Inherent auditory skills rather than formal music training shape the neural encoding of speech

Musical training is associated with a myriad of neuroplastic changes in the brain, including more robust and efficient neural processing of clean and degraded speech signals at brainstem and cortical levels. These assumptions stem largely from cross-sectional studies between musicians and nonmusicians which cannot address whether training itself is sufficient to induce physiological changes or whether preexisting superiority in auditory function before training predisposes individuals to pursue musical interests and appear to have similar neuroplastic benefits as musicians. Here, we recorded neuroelectric brain activity to clear and noise-degraded speech sounds in individuals without formal music training but who differed in their receptive musical perceptual abilities as assessed objectively via the Profile of Music Perception Skills. We found that listeners with naturally more adept listening skills ("musical sleepers") had enhanced frequency-following responses to speech that were also more resilient to the detrimental effects of noise, consistent with the increased fidelity of speech encoding and speech-in-noise benefits observed previously in highly trained musicians. Further comparisons between these musical sleepers and actual trained musicians suggested that experience provides an additional boost to the neural encoding and perception of speech. Collectively, our findings suggest that the auditory neuroplasticity of music engagement likely involves a layering of both preexisting (nature) and experience-driven (nurture) factors in complex sound processing. In the absence of formal training, individuals with intrinsically proficient auditory systems can exhibit musician-like auditory function that can be further shaped in an experience-dependent manner.

The relationship between socioeconomic status and white matter microstructure in pre-reading children: A longitudinal investigation

Reading is a learned skill crucial for educational attainment. Children from families of lower socioeconomic status (SES) tend to have poorer reading performance and this gap widens across years of schooling. Reading relies on the orchestration of multiple neural systems integrated via specific white-matter pathways, but there is limited understanding about whether these pathways relate differentially to reading performance depending on SES background. Kindergarten white-matter FA and second-grade reading outcomes were investigated in an SES-diverse sample of 125 children. The three left-hemisphere white-matter tracts most associated with reading, and their right-hemisphere homologs, were examined: arcuate fasciculus (AF), superior longitudinal fasciculus (SLF), and inferior longitudinal fasciculus (ILF). There was a significant and positive association between SES and fractional anisotropy (FA) in the bilateral ILF in kindergarten. SES moderated the association between kindergarten ILF and second grade reading performance, such that it was positive in lower-SES children, but not significant in higher-SES children. These results have implications for understanding the role of the environment in the development of the neural pathways that support reading.

Childhood socioeconomic status and genetic risk for poorer cognition in later life

The ε4 allele of the APOE gene is associated with poorer cognition in later life. This study aimed to advance understanding of how environments potentially moderate this genetic risk by focusing on childhood socioeconomic status (SES). Previous research across diverse national contexts has found that older adults from higher-SES families in childhood demonstrate better cognitive functioning than their lower-SES counterparts. Nevertheless, few studies have examined whether higher childhood SES might also promote later life cognition by mitigating the effects of ε4 carrier status. To address this gap, we used data from 3017 participants in the Wisconsin Longitudinal Study, which has followed a random sample of people who graduated from Wisconsin high schools in 1957. Childhood SES included parents' educational attainment, father's occupational status, and household income in adolescence. We constructed measures of memory and of language/executive functioning using scores from neurocognitive tests administered when participants were approximately ages 65 and 72. APOE ε4 status was measured through saliva samples. Results from cross-controlled multilevel models indicated that APOE ε4 status-and not childhood SES-independently predicted memory, whereas childhood SES-and not APOE ε4 status-independently predicted language/executive functioning. Moreover, a statistical interaction between APOE ε4 status and childhood SES for memory indicated that at baseline, higher childhood SES protected against the risk of APOE ε4 status, whereas lower childhood SES exacerbated the risk of APOE ε4 status. However, by follow-up, these moderating effects dissipated, and APOE ε4 status alone was associated with memory. We interpret these results in light of theorizing on differential susceptibility for poorer cognition across the life course.

Socioeconomic status is a predictor of neurocognitive performance of early female adolescents

OBJECTIVE

Previous studies have shown that high socioeconomic status (SES) is significantly associated with inhibitory control, working memory, verbal comprehension and IQ. However, in the Asian setting, with its prevailing poverty, information about the influence of SES on cognitive development of female adolescents is limited. This study was aimed to investigate the association between SES and neurocognitive performance of early female adolescents in Sri Lanka.

METHODS

Female adolescents aged 11-14 years (n = 200) of low and middle SES were studied to assess neurocognitive function. After obtaining baseline data, eight subtests of the Wechsler Intelligence Scale for Children (WISC - IV), Test Of Nonverbal Intelligence (TONI-3) and two computer-based executive function tests (inhibition and visuo-spatial working memory) were administered to assess neurocognitive measures of the above adolescents. The results were compiled into a data base and analyzed using SPSS version 20 statistical software.

RESULTS

Higher SES was associated with higher performance in all neurocognitive tests. Low SES adolescents obtained significantly poor test scores for executive function test (inhibitory control: p < 0.0001) and for WISC [verbal comprehension index (VCI): p < 0.0001), working memory index (WMI): p < 0.0001 and estimated full scale IQ (EFSIQ): p < 0.0001)] when compared with middle SES adolescents. Maternal education alone significantly predicts VCI and EFSIQ than the combined influence of parental education, occupation and income. Psychosocial adversities of adolescents were inversely correlated with VCI (r = -0.30; p < 0.001) and EFSIQ (r = -0.20; p < 0.001) of WISC and mathematics performance (r = -0.34; p < 0.001) at examination in school.

CONCLUSION

Findings of the study revealed the importance of upliftment of SES of the society to improve the cognitive and academic outcomes of low SES individuals.

Musical Experience, Sensorineural Auditory Processing, and Reading Subskills in Adults

Developmental research suggests that sensorineural auditory processing, reading subskills (e.g., phonological awareness and rapid naming), and musical experience are related during early periods of reading development. Interestingly, recent work suggests that these relations may extend into adulthood, with indices of sensorineural auditory processing relating to global reading ability. However, it is largely unknown whether sensorineural auditory processing relates to specific reading subskills, such as phonological awareness and rapid naming, as well as musical experience in mature readers. To address this question, we recorded electrophysiological responses to a repeating click (auditory stimulus) in a sample of adult readers. We then investigated relations between electrophysiological responses to sound, reading subskills, and musical experience in this same set of adult readers. Analyses suggest that sensorineural auditory processing, reading subskills, and musical experience are related in adulthood, with faster neural conduction times and greater musical experience associated with stronger rapid-naming skills. These results are similar to the developmental findings that suggest reading subskills are related to sensorineural auditory processing and musical experience in children.

The relationship between maternal education and the neural substrates of phoneme perception in children: Interactions between socioeconomic status and proficiency level

Relationships between maternal education (ME) and both behavioral performances and brain activation during the discrimination of phonemic and nonphonemic sounds were examined using fMRI in children with different levels of phoneme categorization proficiency (CP). Significant relationships were found between ME and intellectual functioning and vocabulary, with a trend for phonological awareness. A significant interaction between CP and ME was seen for nonverbal reasoning abilities. In addition, fMRI analyses revealed a significant interaction between CP and ME for phonemic discrimination in left prefrontal cortex. Thus, ME was associated with differential patterns of both neuropsychological performance and brain activation contingent on the level of CP. These results highlight the importance of examining SES effects at different proficiency levels. The pattern of results may suggest the presence of neurobiological differences in the children with low CP that affect the nature of relationships with ME.

Involvement of the Serotonin Transporter Gene in Accurate Subcortical Speech Encoding

A flourishing line of evidence has highlighted the encoding of speech sounds in the subcortical auditory system as being shaped by acoustic, linguistic, and musical experience and training. And while the heritability of auditory speech as well as nonspeech processing has been suggested, the genetic determinants of subcortical speech processing have not yet been uncovered. Here, we postulated that the serotonin transporter-linked polymorphic region (5-HTTLPR), a common functional polymorphism located in the promoter region of the serotonin transporter gene (SLC6A4), is implicated in speech encoding in the human subcortical auditory pathway. Serotonin has been shown as essential for modulating the brain response to sound both cortically and subcortically, yet the genetic factors regulating this modulation regarding speech sounds have not been disclosed. We recorded the frequency following response, a biomarker of the neural tracking of speech sounds in the subcortical auditory pathway, and cortical evoked potentials in 58 participants elicited to the syllable /ba/, which was presented >2000 times. Participants with low serotonin transporter expression had higher signal-to-noise ratios as well as a higher pitch strength representation of the periodic part of the syllable than participants with medium to high expression, possibly by tuning synaptic activity to the stimulus features and hence a more efficient suppression of noise. These results imply the 5-HTTLPR in subcortical auditory speech encoding and add an important, genetically determined layer to the factors shaping the human subcortical response to speech sounds.

SIGNIFICANCE STATEMENT

The accurate encoding of speech sounds in the subcortical auditory nervous system is of paramount relevance for human communication, and it has been shown to be altered in different disorders of speech and auditory processing. Importantly, this encoding is plastic and can therefore be enhanced by language and music experience. Whether genetic factors play a role in speech encoding at the subcortical level remains unresolved. Here we show that a common polymorphism in the serotonin transporter gene relates to an accurate and robust neural tracking of speech stimuli in the subcortical auditory pathway. This indicates that serotonin transporter expression, eventually in combination with other polymorphisms, delimits the extent to which lifetime experience shapes the subcortical encoding of speech.

Neurobiology of Everyday Communication: What Have We Learned From Music?

Sound is an invisible but powerful force that is central to everyday life. Studies in the neurobiology of everyday communication seek to elucidate the neural mechanisms underlying sound processing, their stability, their plasticity, and their links to language abilities and disabilities. This sound processing lies at the nexus of cognitive, sensorimotor, and reward networks. Music provides a powerful experimental model to understand these biological foundations of communication, especially with regard to auditory learning. We review studies of music training that employ a biological approach to reveal the integrity of sound processing in the brain, the bearing these mechanisms have on everyday communication, and how these processes are shaped by experience. Together, these experiments illustrate that music works in synergistic partnerships with language skills and the ability to make sense of speech in complex, everyday listening environments. The active, repeated engagement with sound demanded by music making augments the neural processing of speech, eventually cascading to listening and language. This generalization from music to everyday communications illustrates both that these auditory brain mechanisms have a profound potential for plasticity and that sound processing is biologically intertwined with listening and language skills. A new wave of studies has pushed neuroscience beyond the traditional laboratory by revealing the effects of community music training in underserved populations. These community-based studies reinforce laboratory work highlight how the auditory system achieves a remarkable balance between stability and flexibility in processing speech. Moreover, these community studies have the potential to inform health care, education, and social policy by lending a neurobiological perspective to their efficacy.

Tuning the mind: Exploring the connections between musical ability and executive functions

A growing body of research suggests that musical experience and ability are related to a variety of cognitive abilities, including executive functioning (EF). However, it is not yet clear if these relationships are limited to specific components of EF, limited to auditory tasks, or reflect very general cognitive advantages. This study investigated the existence and generality of the relationship between musical ability and EFs by evaluating the musical experience and ability of a large group of participants and investigating whether this predicts individual differences on three different components of EF - inhibition, updating, and switching - in both auditory and visual modalities. Musical ability predicted better performance on both auditory and visual updating tasks, even when controlling for a variety of potential confounds (age, handedness, bilingualism, and socio-economic status). However, musical ability was not clearly related to inhibitory control and was unrelated to switching performance. These data thus show that cognitive advantages associated with musical ability are not limited to auditory processes, but are limited to specific aspects of EF. This supports a process-specific (but modality-general) relationship between musical ability and non-musical aspects of cognition.

Beyond Words: How Humans Communicate Through Sound

Every day we communicate using complex linguistic and musical systems, yet these modern systems are the product of a much more ancient relationship with sound. When we speak, we communicate not only with the words we choose, but also with the patterns of sound we create and the movements that create them. From the natural rhythms of speech, to the precise timing characteristics of a consonant, these patterns guide our daily communication. By examining the principles of information processing that are common to speech and music, we peel back the layers to reveal the biological foundations of human communication through sound. Further, we consider how the brain's response to sound is shaped by experience, such as musical expertise, and implications for the treatment of communication disorders.

Bilingual enhancements have no socioeconomic boundaries

To understand how socioeconomic status (SES) and bilingualism simultaneously operate on cognitive and sensory function, we examined executive control, language skills, and neural processing of sound in adolescents who differed in language experience (i.e. English monolingual or Spanish-English bilingual) and level of maternal education (a proxy for SES). We hypothesized that experience communicating in two languages provides an enriched linguistic environment that can bolster neural precision in subcortical auditory processing which, in turn, enhances cognitive and linguistic function, regardless of the adolescent's socioeconomic standing. Consistent with this, we report that adolescent bilinguals of both low and high SES demonstrate more stable neural responses, stronger phonemic decoding skills, and heightened executive control, relative to their monolingual peers. These results support the argument that bilingualism can bolster cognitive and neural function in low-SES children and suggest that strengthened neural response consistency provides a biological mechanism through which these enhancements occur.