Concussion acutely disrupts auditory processing in division I football student-athletes.

INTRODUCTION: Diagnosis, assessment, and management of sports-related concussion require a multi-modal approach. Yet, currently, an objective assessment of auditory processing is not included. The auditory system is uniquely complex, relying on exquisite temporal precision to integrate signals across many synapses, connected by long axons. Given this complexity and precision, together with the fact that axons are highly susceptible to damage from mechanical force, we hypothesize that auditory processing is susceptible to concussive injury. METHODS: We measured the frequency-following response (FFR), a scalp-recorded evoked potential that assesses processing of complex sound features, including pitch and phonetic identity. FFRs were obtained on male Division I Collegiate football players prior to contact practice to determine a pre-season baseline of auditory processing abilities, and again after sustaining a sports-related concussion. We predicted that concussion would decrease pitch and phonetic processing relative to the student-athlete's preseason baseline. RESULTS: We found that pitch and phonetic encoding was smaller post-concussion. Student-athletes who sustained a second concussion showed similar declines after each injury. CONCLUSIONS: Auditory processing should be included in the multimodal assessment of sports-related concussion. Future studies that extend this work to other sports, other injuries (e.g. blast exposure), and to female athletes are needed.

Multiple Cases of Auditory Neuropathy Illuminate the Importance of Subcortical Neural Synchrony for Speech-in-noise Recognition and the Frequency-following Response.

OBJECTIVES: The role of subcortical synchrony in speech-in-noise (SIN) recognition and the frequency-following response (FFR) was examined in multiple listeners with auditory neuropathy. Although an absent FFR has been documented in one listener with idiopathic neuropathy who has severe difficulty recognizing SIN, several etiologies cause the neuropathy phenotype. Consequently, it is necessary to replicate absent FFRs and concomitant SIN difficulties in patients with multiple sources and clinical presentations of neuropathy to elucidate fully the importance of subcortical neural synchrony for the FFR and SIN recognition. DESIGN: Case series. Three children with auditory neuropathy (two males with neuropathy attributed to hyperbilirubinemia, one female with a rare missense mutation in the OPA1 gene) were compared to age-matched controls with normal hearing (52 for electrophysiology and 48 for speech recognition testing). Tests included standard audiological evaluations, FFRs, and sentence recognition in noise. The three children with neuropathy had a range of clinical presentations, including moderate sensorineural hearing loss, use of a cochlear implant, and a rapid progressive hearing loss. RESULTS: Children with neuropathy generally had good speech recognition in quiet but substantial difficulties in noise. These SIN difficulties were somewhat mitigated by a clear speaking style and presenting words in a high semantic context. In the children with neuropathy, FFRs were absent from all tested stimuli. In contrast, age-matched controls had reliable FFRs. CONCLUSION: Subcortical synchrony is subject to multiple forms of disruption but results in a consistent phenotype of an absent FFR and substantial difficulties recognizing SIN. These results support the hypothesis that subcortical synchrony is necessary for the FFR. Thus, in healthy listeners, the FFR may reflect subcortical neural processes important for SIN recognition.

Case studies in neuroscience: cortical contributions to the frequency-following response depend on subcortical synchrony.

Frequency-following responses to musical notes spanning the octave 65-130 Hz were elicited in a person with auditory neuropathy, a disorder of subcortical neural synchrony, and a control subject. No phaselocked responses were observed in the person with auditory neuropathy. The control subject had robust responses synchronized to the fundamental frequency and its harmonics. Cortical onset responses to each note in the series were present in both subjects. These results support the hypothesis that subcortical neural synchrony is necessary to generate the frequency-following response-including for stimulus frequencies at which a cortical contribution has been noted. Although auditory cortex ensembles may synchronize to fundamental frequency cues in speech and music, subcortical neural synchrony appears to be a necessary antecedent.NEW & NOTEWORTHY A listener with auditory neuropathy, an absence of subcortical neural synchrony, did not have electrophysiological frequency-following responses synchronized to an octave of musical notes, with fundamental frequencies ranging from 65 to 130 Hz. A control subject had robust responses that phaselocked to each note. Although auditory cortex may contribute to the scalp-recorded frequency-following response in healthy listeners, our results suggest this phenomenon depends on subcortical neural synchrony.

Performance on auditory, vestibular, and visual tests is stable across two seasons of youth tackle football.

Objective: Few studies have tracked neurologic function in youth football players longitudinally. This study aimed to determine whether changes in tests of auditory, vestibular, and/or visual functions are evident after participation in one or two seasons of youth tackle football.Study Design: Prospective cohort study.Subjects and Methods: Before their 2017 and/or 2018 seasons, male tackle football players (ages 7-14 yrs) completed three tests that tend to exhibit acute disruptions following a concussion: (1) the FFR (frequency-following response), aphysiologic test of auditory function, (2) the BESS (Balance Error Scoring System), a test of vestibular function, and (3) the King-Devick, a test of oculomotor function. We planned to repeat these on all subjects at the end of each season.Results: Performance on neurosensory tests was stable, with no changes observed in FFR or King-Devick and a slight improvement observed in BESS performance across each season. Performance was also stable over two years for the subjects who participated both years. Across-season test-retest reliability correlations were high.Conclusions: In the absence of concussion, young athletes' performance on the FFR, King-Devick, and BESS is stable across one or two seasons of youth tackle football.

Distinct rhythmic abilities align with phonological awareness and rapid naming in school-age children.

Difficulty in performing rhythmic tasks often co-occurs with literacy difficulties. Motivated by evidence showing that people can vary in their performance across different rhythmic tasks, we asked whether two rhythmic skills identified as distinct in school-age children and young adults would reveal similar or different relationships with two literacy skills known to be important for successful reading development. We addressed our question by focusing on 55 typically developing children (ages 5-8). Results show that drumming to a beat predicted the variability of rapid naming but not of phonological awareness, whereas tapping rhythmic patterns predicted phonological awareness, but not rapid naming. Our finding suggests that rhythmic interventions can be tailored to address PA and RAN deficits specifically in reading disabled children.

Case studies in neuroscience: subcortical origins of the frequency-following response.

The auditory frequency-following response (FFR) reflects synchronized and phase-locked activity along the auditory pathway in response to sound. Although FFRs were historically thought to reflect subcortical activity, recent evidence suggests an auditory cortex contribution as well. Here we present electrophysiological evidence for the FFR's origins from two cases: a patient with bilateral auditory cortex lesions and a patient with auditory neuropathy, a condition of subcortical origin. The patient with auditory cortex lesions had robust and replicable FFRs, but no cortical responses. In contrast, the patient with auditory neuropathy had no FFR despite robust and replicable cortical responses. This double dissociation shows that subcortical synchrony is necessary and sufficient to generate an FFR.NEW & NOTEWORTHY The frequency-following response (FFR) reflects synchronized and phase-locked neural activity in response to sound.  The authors present a dual case study, comparing FFRs and cortical potentials between a patient with auditory neuropathy (a condition of subcortical origin) and a patient with bilateral auditory cortex lesions. They show that subcortical synchrony is necessary and sufficient to generate an FFR.

Auditory Processing in Noise: A Preschool Biomarker for Literacy.

Learning to read is a fundamental developmental milestone, and achieving reading competency has lifelong consequences. Although literacy development proceeds smoothly for many children, a subset struggle with this learning process, creating a need to identify reliable biomarkers of a child's future literacy that could facilitate early diagnosis and access to crucial early interventions. Neural markers of reading skills have been identified in school-aged children and adults; many pertain to the precision of information processing in noise, but it is unknown whether these markers are present in pre-reading children. Here, in a series of experiments in 112 children (ages 3-14 y), we show brain-behavior relationships between the integrity of the neural coding of speech in noise and phonology. We harness these findings into a predictive model of preliteracy, revealing that a 30-min neurophysiological assessment predicts performance on multiple pre-reading tests and, one year later, predicts preschoolers' performance across multiple domains of emergent literacy. This same neural coding model predicts literacy and diagnosis of a learning disability in school-aged children. These findings offer new insight into the biological constraints on preliteracy during early childhood, suggesting that neural processing of consonants in noise is fundamental for language and reading development. Pragmatically, these findings open doors to early identification of children at risk for language learning problems; this early identification may in turn facilitate access to early interventions that could prevent a life spent struggling to read.

Individual Differences in Human Auditory Processing: Insights From Single-Trial Auditory Midbrain Activity in an Animal Model.

Auditory-evoked potentials are classically defined as the summations of synchronous firing along the auditory neuraxis. Converging evidence supports a model whereby timing jitter in neural coding compromises listening and causes variable scalp-recorded potentials. Yet the intrinsic noise of human scalp recordings precludes a full understanding of the biological origins of individual differences in listening skills. To delineate the mechanisms contributing to these phenomena, in vivo extracellular activity was recorded from inferior colliculus in guinea pigs to speech in quiet and noise. Here we show that trial-by-trial timing jitter is a mechanism contributing to auditory response variability. Identical variability patterns were observed in scalp recordings in human children, implicating jittered timing as a factor underlying reduced coding of dynamic speech features and speech in noise. Moreover, intertrial variability in human listeners is tied to language development. Together, these findings suggest that variable timing in inferior colliculus blurs the neural coding of speech in noise, and propose a consequence of this timing jitter for human behavior. These results hint both at the mechanisms underlying speech processing in general, and at what may go awry in individuals with listening difficulties.

Difficulty hearing in noise: a sequela of concussion in children.

OBJECTIVE: Concussions can result in auditory processing deficits even in the absence of hearing loss. In children and adolescents, the extent to which these impairments have functional consequences for everyday listening, such as the ability to understand speech in noisy environments, is unknown. RESEARCH DESIGN: Case-control study. SUBJECTS AND METHODS: Forty youth comprised the participants: 20 had sustained a concussion and were recovering from their injury, and 20 controls had sustained non-concussive orthopaedic (e.g. musculoskeletal) injuries. All were evaluated on the Hearing in Noise Test, an audiologic index of the ability to hear sentences in adverse listening conditions. RESULTS: Children and adolescents recovering from concussions demonstrated an overall impaired ability to perceive speech in noisy backgrounds compared to a peer control group. This deficit also emerged across trials in the most taxing listening condition, and with respect to published, age-normative values. CONCLUSIONS: Functional listening skills-such as the ability to understand speech in noise, and the ability to sustain performance over time in taxing auditory conditions-may be compromised in children with concussions. These impairments may exacerbate cognitive and academic challenges associated with concussion injuries, and should be considered in return-to-learn and return-to-play decisions.

Variations on the theme of musical expertise: cognitive and sensory processing in percussionists, vocalists and non-musicians.

Comparisons of musicians and non-musicians have revealed enhanced cognitive and sensory processing in musicians, with longitudinal studies suggesting these enhancements may be due in part to experience-based plasticity. Here, we investigate the impact of primary instrument on the musician signature of expertise by assessing three groups of young adults: percussionists, vocalists, and non-musician controls. We hypothesize that primary instrument engenders selective enhancements reflecting the most salient acoustic features to that instrument, whereas cognitive functions are enhanced regardless of instrument. Consistent with our hypotheses, percussionists show more precise encoding of the fast-changing acoustic features of speech than non-musicians, whereas vocalists have better frequency discrimination and show stronger encoding of speech harmonics than non-musicians. There were no strong advantages to specialization in sight-reading vs. improvisation. These effects represent subtle nuances to the signature since the musician groups do not differ from each other in these measures. Interestingly, percussionists outperform both non-musicians and vocalists in inhibitory control. Follow-up analyses reveal that within the vocalists and non-musicians, better proficiency on an instrument other than voice is correlated with better inhibitory control. Taken together, these outcomes suggest the more extensive engagement of motor systems during instrumental practice may be an important factor for enhancements in inhibitory control, consistent with evidence for overlapping neural circuitry involved in both motor and cognitive control. These findings contribute to the ongoing refinement of the musician signature of expertise and may help to inform the use of music in training and intervention to strengthen cognitive function.

Music enrichment programs improve the neural encoding of speech in at-risk children.

Musicians are often reported to have enhanced neurophysiological functions, especially in the auditory system. Musical training is thought to improve nervous system function by focusing attention on meaningful acoustic cues, and these improvements in auditory processing cascade to language and cognitive skills. Correlational studies have reported musician enhancements in a variety of populations across the life span. In light of these reports, educators are considering the potential for co-curricular music programs to provide auditory-cognitive enrichment to children during critical developmental years. To date, however, no studies have evaluated biological changes following participation in existing, successful music education programs. We used a randomized control design to investigate whether community music participation induces a tangible change in auditory processing. The community music training was a longstanding and successful program that provides free music instruction to children from underserved backgrounds who stand at high risk for learning and social problems. Children who completed 2 years of music training had a stronger neurophysiological distinction of stop consonants, a neural mechanism linked to reading and language skills. One year of training was insufficient to elicit changes in nervous system function; beyond 1 year, however, greater amounts of instrumental music training were associated with larger gains in neural processing. We therefore provide the first direct evidence that community music programs enhance the neural processing of speech in at-risk children, suggesting that active and repeated engagement with sound changes neural function.

Persistent post-concussion symptoms include neural auditory processing in young children.

Aim: Difficulty understanding speech following concussion is likely caused by auditory processing impairments. We hypothesized that concussion disrupts pitch and phonetic processing of a sound, cues in understanding a talker. Patients & methods/results: We obtained frequency following responses to a syllable from 120 concussed and 120 control. Encoding of the fundamental frequency (F0), a pitch cue and the first formant (F1), a phonetic cue, was poorer in concussed children. The F0 reduction was greater in the children assessed within 2 weeks of their injuries. Conclusion: Concussions affect auditory processing. Results strengthen evidence of reduced F0 encoding in children with concussion and call for longitudinal study aimed at monitoring the recovery course with respect to the auditory system.

Auditory neural processing in children living with HIV uncovers underlying central nervous system dysfunction.

OBJECTIVE: Central nervous system (CNS) damage from HIV infection or treatment can lead to developmental delays and poor educational outcomes in children living with HIV (CLWH). Early markers of central nervous system dysfunction are needed to target interventions and prevent life-long disability. The frequency following response (FFR) is an auditory electrophysiology test that can reflect the health of the central nervous system. In this study, we explore whether the FFR reveals auditory central nervous system dysfunction in CLWH. STUDY DESIGN: Cross-sectional analysis of an ongoing cohort study. Data were from the child's first visit in the study. SETTING: The infectious disease center in Dar es Salaam, Tanzania. METHODS: We collected the FFR from 151 CLWH and 151 HIV-negative children. To evoke the FFR, three speech syllabi (/da/, /ba/, /ga/) were played monaurally to the child's right ear. Response measures included neural timing (peak latencies), strength of frequency encoding (fundamental frequency and first formant amplitude), encoding consistency (inter-response consistency), and encoding precision (stimulus-to-response correlation). RESULTS: CLWH showed smaller first formant amplitudes ( P  < 0.0001), weaker inter-response consistencies ( P  < 0.0001) and smaller stimulus to response correlations ( P  < 0.0001) than FFRs from HIV-negative children. These findings generalized across the three speech stimuli with moderately strong effect sizes (partial η2 ranged from 0.061 to 0.094). CONCLUSION: The FFR shows auditory central nervous system dysfunction in CLWH. Neural encoding of auditory stimuli was less robust, more variable, and less accurate. As the FFR is a passive and objective test, it may offer an effective way to assess and detect central nervous system function in CLWH.

Subconcussion revealed by sound processing in the brain.

Introduction/Purpose: We tested the hypothesis that an objective measure of auditory processing reveals a history of head trauma that does not meet the clinical definition of concussion. Methods: Division I collegiate student-athletes (n = 709) across 19 sports were divided into groups, based on their sport, using prevailing classifications of "contact" (317 males, 212 females) and "noncontact" (58 males, 122 females). Participants were evaluated using the frequency-following response (FFR) to speech. The amplitude of FFR activity in a frequency band corresponding to the fundamental frequency (F0)-the voice pitch-of the speech stimulus, an outcome reduced in individuals with concussions, was critically examined. Results: We found main effects of contact level and sex. The FFR-F0 was smaller in contact athletes than noncontact athletes and larger in females than males. There was a contact by sex interaction, with the FFR-F0 of males in the contact group being smaller than the three other groups. Secondary analyses found a correlation between FFR-F0 and length of participation in contact sports in male athletes. Conclusion: These findings suggest that the disruption of sensory processing in the brain can be observed in individuals without a concussion but whose sport features regular physical contact. This evidence identifies sound processing in the brain as an objective marker of subconcussion in athletes.

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.

Peripheral Auditory Function in Tanzanian Children Living With HIV With Clinically Normal Hearing.

Importance: Despite normal audiometry, adults living with HIV have lower distortion product otoacoustic emissions (DPOAEs) compared with HIV-negative controls, but the degree of these differences in children living with HIV is unknown. If subclinical auditory deficits are present, results could affect developmental outcomes in children living with HIV (CLWH). Objective: To compare DPOAEs and auditory brainstem responses (ABR) between 2 age- and sex-matched groups of younger children with normal audiometry, 1 infected with HIV and the other uninfected. Design, Setting, and Participants: Cohort study in an infectious disease center in Dar es Salaam, Tanzania. Participants included 340 Tanzanian children aged 3 to 9 years with clinically normal hearing, type A tympanograms bilaterally, and air-conduction thresholds of 20 dB HL or less from 0.5 to 8 kHz. Participants in the cohort repeated testing approximately every 6 months (approximately 2.2 sessions per participant) for a total of 744 total observations. Data were analyzed from March 2020 to January 2022. Main Outcomes and Measures: DPOAE amplitudes from 1.5 to 8 kHz using an f2 to f1 ratio of 1.2 and L1/L2 values of 65/55 dB sound pressure level and click-evoked ABR using a slow (21.1/s) and fast (61.1/s) click rate. Results: A total of 141 CLWH (70 female participants [49.3%]; mean [SD] age, 7.24 [1.67] years) and 199 HIV-negative individuals (99 female participants [49.7%]; mean [SD] age, 7.26 [1.44] years) participated in the study. The groups did not differ significantly in age, static immittance, or air-conduction thresholds. HIV status was independently associated with approximately 1.4 dB (95% CI, -3.28 to 0.30 dB) to 3.8 dB (95% CI, 6.03 to -1.99 dB) lower DPOAE amplitudes at 6 and 8 kHz bilaterally and 0.28 µV (95% CI, 0.01 to 0.33 µV) lower ABR wave V amplitudes in the right ear. Conclusions and Relevance: Consistent with previous findings in young adults, CLWH had slightly, but reliably, lower DPOAEs and ABR wave V amplitudes than HIV-negative controls. The magnitude of these differences was small, but results suggest an early and consistent association between HIV infection or treatment and outer hair cell and auditory brainstem responses in children as young as 3 years. These subclinical changes suggest tracking both auditory function and development outcomes in CLWH is warranted.

Preliteracy assessment in children living with HIV in Tanzania: comparison to results from children living without HIV in Tanzania and the United States.

OBJECTIVE: Children with HIV (CWH) are at increased risk for cognitive and developmental delays. Whether HIV affects literacy development, however, remains unknown. Rapid automatized naming (RAN) tasks offer the simplest preliteracy assessment a child can perform that predicts future reading skills across languages. DESIGN AND METHODS: RAN performance was analyzed cross-sectionally on 473 children (249 children without HIV and 217 CWH; ages 3-9) drawn from a longitudinal study in Tanzania. These data were compared to results from 341 normally developing children without HIV (ages 3-8) from the United States. Participants performed two RAN subtests: colors and objects. RESULTS: RAN object completion was greater than for the RAN color in Tanzanian children. CWH were less likely to complete either subtest and performed worse on the object subtest compared to Tanzanian children without HIV. Compared to the US cohort, the Tanzanian cohort was less likely to complete both subtests - in particular the colors subtest - and showed more variability in responses at younger ages. After approximately age 6, however, the trajectory of improvement between the United States and Tanzania was similar. CONCLUSIONS: CWH performed worse on this per-literacy test, indicating literacy skill development in CWH needs further study. The differences between US and Tanzanian results likely reflect variability in when children learn to name colors and objects. The trajectory of improvement between countries became more similar as the children aged. This study motivates further longitudinal analyses aimed at assessing the developmental trajectory of the RAN, its predictive ability for reading skills, and its link with other preliteracy and cognitive skills.

Subcortical differentiation of stop consonants relates to reading and speech-in-noise perception.

Children with reading impairments have deficits in phonological awareness, phonemic categorization, speech-in-noise perception, and psychophysical tasks such as frequency and temporal discrimination. Many of these children also exhibit abnormal encoding of speech stimuli in the auditory brainstem, even though responses to click stimuli are normal. In typically developing children the auditory brainstem response reflects acoustic differences between contrastive stop consonants. The current study investigated whether this subcortical differentiation of stop consonants was related to reading ability and speech-in-noise performance. Across a group of children with a wide range of reading ability, the subcortical differentiation of 3 speech stimuli ([ba], [da], [ga]) was found to be correlated with phonological awareness, reading, and speech-in-noise perception, with better performers exhibiting greater differences among responses to the 3 syllables. When subjects were categorized into terciles based on phonological awareness and speech-in-noise performance, the top-performing third in each grouping had greater subcortical differentiation than the bottom third. These results are consistent with the view that the neural processes underlying phonological awareness and speech-in-noise perception depend on reciprocal interactions between cognitive and perceptual processes.

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.

Peripheral Auditory Function in Young HIV-Positive Adults With Clinically Normal Hearing.

OBJECTIVE: Little is known about peripheral auditory function in young adults with HIV, who might be expected to show early evidence of hearing loss if HIV infection or treatment does affect peripheral function. The goal of this study was to compare peripheral auditory function in 2 age- and gender-matched groups of young adults with clinically normal hearing with and without HIV. STUDY DESIGN: Matched cohort study with repeated measures. SETTING: Infectious disease center in Dar es Salaam, Tanzania. METHODS: Participants included HIV-positive (n = 38) and HIV-negative (n = 38) adults aged 20 to 30 years who had clinically normal hearing, defined as type A tympanograms, air conduction thresholds ≤25 dB HL bilaterally from 0.5 to 8 kHz, and distortion product otoacoustic emissions (DPOAEs) >6 dB above the noise floor bilaterally from 1.5 to 8 kHz. Participants were tested multiple times over 6-month intervals (average, 2.7 sessions/participant) for a total of 208 observations. Primary outcome measures included tympanograms, air conduction audiograms, DPOAEs, and click-evoked auditory brainstem responses. RESULTS: HIV groups did not significantly differ in age, static immittance, or air conduction thresholds. HIV-positive status was independently associated with approximately 3.7-dB lower DPOAE amplitudes from 2 to 8 kHz (95% CI, 1.01-6.82) in both ears and 0.04-µV lower (95% CI, 0.003-0.076) auditory brainstem response wave I amplitudes in the right ear. CONCLUSION: Young adults living with HIV have slightly but reliably smaller DPOAEs and auditory brainstem response wave I amplitudes than matched HIV-negative controls. The magnitude of these differences is small, but these results support measuring peripheral auditory function in HIV-positive individuals as they age.