Peripheral Auditory System Research Articles

Impacts of impaired mitochondrial dynamics in hearing loss: Potential therapeutic targets.

Mitochondria are the powerhouse of the cells. Under physiological conditions, mitochondrial fission and fusion maintain a dynamic equilibrium in the cytoplasm, which is referred to as mitochondrial dynamics. As an important approach to regulating mitochondrial function and quantity, the role of mitochondrial dynamics has been demonstrated in the pathogenesis of various disease models, including brain damage, neurodegeneration, and stress. As the vital organ of the peripheral auditory system, the cochlea consumes a significant amount of energy, and the maintenance of mitochondrial homeostasis is essential for the cochlear auditory capacity. OPA1 functions as both a necessary gene regulating mitochondrial fusion and a pathogenic gene responsible for auditory neuropathy, suggesting that an imbalance in mitochondrial dynamics may play a critical role in hearing loss, but relevant studies are few. In this review, we summarize recent evidence regarding the role of mitochondrial dynamics in the pathogenesis of noise-induced hearing loss (NIHL), drug-induced hearing loss, hereditary hearing loss, and age-related hearing loss. The impacts of impaired mitochondrial dynamics on hearing loss are discussed, and the potential of mitochondrial dynamics for the prevention and treatment of hearing loss is considered.

Diagnostic value and prognostic significance of MRI findings in sudden sensorineural hearing loss.

PurposeWe evaluated the clinical significance of magnetic resonance imaging (MRI) findings and their prognostic value for initial hearing loss and recovery in patients with sudden sensorineural hearing loss (SSNHL).Materials and MethodsThis retrospective study included consecutive adult patients with unilateral SSNHL, contrast‐enhanced MRI and audiometric testing evaluated in our institution between 2005 and 2017. MRI reports, patient data, treatment, and audiometric tests were reviewed, with the relationship between MRI findings and hearing loss/recovery analyzed.ResultsOverall, 266 patients were included. Additional symptoms comprised tinnitus (114/266; 43%), vertigo (45/266; 17%), ear pain (26/266; 10%), and ear pressure (6/266; 2%). At least one cardiovascular risk factor (hypertension, diabetes, hypercholesterolemia, cardiopathy, and active smoking) existed in 167/266 (63%) patients. Corticosteroid treatment was followed by 198/266 (74%) patients while contraindications/refusal/compliance precluded treatment in 68/266(26%). Complete, partial or slight hearing recovery occurred in 167/266 (63%) patients. Three MRI patient groups were identified: a group with normal MRI examinations or incidentalomas (128/266; 48%), a group with peripheral auditory system (PAS) lesions (95/266; 36%), and a group with central nervous system (CNS) lesions (43/266; 16%). PAS lesions included lesions from the cochlea to the brain stem (e.g., schwannoma, meningioma, labyrinthitis, intracochlear hemorrhage, vestibulocochlear neuritis), whereas CNS lesions corresponded in 42/43(98%) of cases to leukoaraiosis and other vascular lesions (e.g., stroke, hemorrhage, aneurysm, venous sinus thrombosis, and cavernoma). Belonging to one of the three MRI groups did not influence the degree of initial hearing loss, affected frequencies or treatment, p > .05. Gender and cardiovascular risk factors did neither affect initial hearing loss nor recovery. However, age > 70 years negatively affected initial hearing loss in all frequencies, as well as recovery in all frequencies except 1000 Hz. Also, poor recovery of initial high‐frequency hearing loss (>1000 Hz) was significantly associated with CNS lesions.ConclusionAge > 70 years and CNS lesions depicted by MRI independently predicted poor auditory recovery, albeit in different frequencies.Lay SummaryIn patients with sudden hearing loss, older age (above 70 years) predicts poorer hearing recovery than in younger patients in most hearing frequencies. In addition, abnormalities of brain tissue revealed by MRI predict poorer hearing recovery at high frequencies.Level of EvidenceLevel III.

Effect of menstrual cycle on outer hair cells (OHC’s) and efferent auditory pathway in females – An Indian study

Menstrual cycle occurs in females every months for ones where the endometrium which is the thick lining of the uterus wall where the fertilized egg is attached during pregnancy, this will shed every month. Sodium, chloride, and water reabsorption capacity increases by high-level progesterone during this period. When there is a change in water and sodium reabsorption which may in term affect the functioning of the auditory system especially peripheral auditory system. Otoacoustic emissions (OAE’s) arise from outer hair cells (OHC’s) which is situated on the basilar membrane that is seen inside the inner ear. The changes in the hormonal levels during the menstrual cycle has a clinically less significant effect on the suppression of TEOAE’s, one of the type of OAE. The current study targeted the testing during three different phases of the menstrual cycle (Day 1 to Day 28) - Follicular phase, Ovulation phase and Luteal phase. The amount of suppression (3dB) caused during different phases of the menstrual cycle for each individual frequencies was compared and analyzed. The study shows that TEOAE, CSTEOAE’s and suppression did not exhibit any statistically significant differences at all the frequencies between the different phases of the menstrual cycle. There are no significant correlation findings between menstrual cycle and outer hair cell function, and menstrual cycle and efferent auditory pathway functioning, considering the complaints of hearing and balance problem during the menstrual cycle period by.

KNOWLEDGE AND ATTITUDE ABOUT MANAGEMENT OF HYPERACUSIS AMONG SPEECH AND HEARING PG STUDENTS

Hyperacusis is dened as a reduced tolerance to sounds of average intensity, sometimes accompanied by painful sensitivity to ordinary environmental sounds, with perceptual, psychological, and social dimensions (Stadio et. al, 2018). Common etiologies of Hyperacusis can be associated with various pathologic conditions related to peripheral auditory system as well as central nervous system diseases. Patients with hyperacusis are misdiagnosed to have tinnitus and because of not getting proper assessment the patient having no benet from the intervention. In the present study, an attempt has made to adapt, modify & validate the Questionnaire developed by Mr. Suman Kumar et. al.,(2014) on Awareness of hyperacusis management among hearing health care professionals - a nationwide telephonic survey in to Knowledge and Attitude about management of Hyperacusis among Speech and Hearing PG students in Bengaluru, Karnataka by sending a questionnaire which consist of 15 questions to Speech and Hearing PG students through various online mode. It was found that 84.89% participants were aware about hyperacusis. 86.04 % of participants had correct knowledge about assessment of hyperacusis. 78.48% participants reported correct responses about management of Hyperacusis. Assessment and management of Hyperacusis needs to be done carefully because quality of life is the primary importance in treatment for individual with hyperacusis.

Electrically evoked auditory brainstem responses in deaf patients with Mondini malformation during cochlear implantation.

To investigate the auditory pathway functions in deaf patients with Mondini malformation using the electrically evoked auditory brainstem response (EABR) during cochlear implantation (CI). A total of 58 patients with severe to profound sensorineural hearing loss (SNHL) were included in this study. Of these patients, 27 cases had Mondini malformation and 31 control cases had no inner ear malformations (IEMs). Intraoperative EABRs evoked by electrical stimulation at the round window niche (RWN) and round window membrane (RWM) were recorded. Patients with Mondini malformation showed significantly lower EABR extraction rates than those with no IEMs did. However, for patients who showed EABRs, no significant difference in EABR thresholds, wave III (eIII) latencies, wave V (eV) latencies or eIII-eV latency intervals was found between two groups. The physiological functions of the peripheral auditory system in patients with Mondini malformation may divide into opposite extremes, as revealed by a robust EABR and the absence of the EABR, respectively. The auditory conduction function should be objectively and individually evaluated for patients with Mondini malformation by the EABR.

Characterizing Electrophysiological Response Properties of the Peripheral Auditory System Evoked by Phonemes in Normal and Hearing Impaired Ears.

This study aimed to characterize time and spectral domain characteristics of the phoneme-evoked electrocochleography (ECochG) response and explore potential associations between the ECochG spectral content, word recognition scores (WRSs), residual hearing, and aging in normal and hearing-impaired listeners. This was a prospective study with 25 adult participants. All participants underwent intraoperative ECochG testing and responses were recorded from the round window niche. Participants were divided into two groups based on their preoperative pure tone average: normal/mild sensorineural hearing loss and moderate/moderately-severe sensorineural hearing loss. Target stimuli were a 40 ms /da/ and an 80 ms /ba/ presented in alternating polarity (rarefaction/condensation). Waveform response patterns were analyzed including amplitude, latency, and spectra. Structural similarity index measure (SSIM) was used to determine similarity between the stimulus spectrum and that of the ECochG differential waveform. Correlation analyses were carried out among pure tone average, SSIM, age, and WRS. ECochG alternating waveform morphology evoked by the /da/ stimulus consisted of five prominent peaks labeled N 1 -N 5 . Its spectrum was dominated by the fundamental (F 0 ) frequency. The ECochG alternating response evoked by /ba/ consisted of nine prominent peaks labeled N 1 -N 9 and was also dominated by F 0 . Amplitudes and latencies were not statistically different between groups for both stimuli. Significant positive correlations were found between SSIM and WRS for responses evoked by /da/ (r = 0.56) and responses evoked by /ba/ (r = 0.67). High frequency pure tone average and the /ba/ SSIM were found to have a significant negative correlation (r = -0.58). Speech-like stimuli have become increasingly utilized in the assessment of auditory function. Here, we provided the groundwork for understanding how commonly employed syllable stimuli are encoded by the peripheral auditory system in regard to temporal and spectral characteristics. Expanding this work to include measurements of central auditory processing in conjunction with cochlear physiology is warranted to further understand the relationship between peripheral and central encoding of speech-like stimuli.

Software implementation of the information model of the peripheral auditory system for assessing speech intelligibility

The paper considers the features of constructing an information model of the human peripheral auditory system in the LabVIEW software environment. A brief description of the adopted information model proposed for implementation in the software environment is given. Detailed explanations are described for each element of the model made in the LabVIEW environment. The main functionality of the user part of the program is presented. The work is, in fact, staged in nature and offers a sequence of further necessary studies of the developed model.

On the Difference of Scoring in Speech in Babble Tests.

Hearing is a complex ability that extends beyond the peripheral auditory system. A speech in noise/competition test is a valuable measure to include in the test battery when attempting to assess an individual’s “hearing”. The present study compared syllable vs. word scoring of the Greek Speech-in-Babble (SinB) test with 22 native Greek speaking children (6–12-year-olds) diagnosed with auditory processing disorder (APD) and 33 native Greek speaking typically developing children (6–12-year-olds). A three-factor analysis of variance revealed greater discriminative ability for syllable scoring than word scoring, with significant interactions between group and scoring. Two-way analysis of variance revealed SinB word-based measures (SNR50%) were larger (poorer performance) than syllable-based measures for both groups of children. Cohen’s d values were larger for syllable-based mean scores compared to word-based mean scores between groups for both ears. These findings indicate that the type of scoring affects the SinB’s resolution capacity and that syllable scoring might better differentiate typically developing children and children with APD.

Peripheral Auditory System Divergence Does Not Explain Species Differences in Call Preference

Receiver sensory systems have long been cited as an important source of variation in mate preferences that could lead to signal diversification and behavioral isolation between lineages, with a general assumption that animals prefer the most conspicuous signals. The matched filter hypothesis posits that tuning of the frog peripheral auditory system matches dominant frequencies in advertisement calls used to attract mates. However, little work has characterized species with frequency modulation in their calls. In this study, we extend prior work characterizing the lack of correlated evolution between auditory tuning and spectral properties of male calls in Engystomops (=Physalaemus) frogs. We analyze auditory sensitivity of three cryptic species that differ consistently in female mate preferences for calls of different frequencies. The audiograms of these species differ, but the frequency at which the frog is maximally sensitive is not the most relevant difference in tuning of the auditory periphery. Rather, we identify species differences in overall sensitivity within specific frequency ranges, and we model the effects of these sensitivity differences on neural responses to natural calls. We find a general mismatch between auditory brainstem responses and behavioral preferences of these taxa and rule out the matched filter hypothesis as explaining species differences in male calls and mate preferences in this group.

Characterizing Polarity Sensitivity in Cochlear Implant Recipients: Demographic Effects and Potential Implications for Estimating Neural Health.

Stimulus polarity can affect both physiological and perceptual measures in cochlear-implant recipients. Large differences between polarities for various outcome measures (e.g., eCAP threshold, amplitude, or slope) theoretically reflect poorer neural health, whereas smaller differences reflect better neural health. Therefore, we expect large polarity effects to be correlated with other measures shown to contribute to poor neural health, such as advanced age or prolonged deafness. Our earlier studies using the electrically evoked compound action potential (eCAP) demonstrated differences in polarity effects between users of Cochlear and Advanced Bionics devices when device-specific clinical pulse designs were used. Since the stimuli differed slightly between devices, the first goal of this study was to determine whether small, clinically relevant differences in pulse phase duration (PD) have a significant impact on eCAP polarity effects to potentially explain the device differences observed previously. Polarity effects were quantified as the difference in eCAP thresholds, mean normalized amplitudes, and slope of the amplitude growth function obtained for anodic-first versus cathodic-first biphasic pulses. The results showed that small variations in PD did not explain the observed differences in eCAP polarity effects between devices. Therefore, eCAP polarity sensitivity measures are relatively robust to small differences in pulse parameters. However, it remains unclear what underlies the observed manufacturer differences, which may limit the utility of eCAP polarity sensitivity measures. The second goal was to characterize polarity sensitivity in a large group of CI recipients (65 ears) to relate polarity sensitivity to age and duration of deafness as a proxy for neural health. The same pulse parameters were used for both device groups. The only significant predictors of eCAP polarity effects were age for threshold and amplitude polarity effects for Cochlear recipients and age and duration of deafness for slope for AB recipients. However, three of these four correlations were in the opposite direction of what was expected. These results suggest that eCAP polarity sensitivity measures likely reflect different mechanisms than the effects that age and duration of deafness induce on the peripheral auditory system.

The Ototoxicity of Chloroquine and Hydroxychloroquine: A Systematic Review.

Introduction Chloroquine and hydroxychloroquine are antimalarial drugs widely used in the treatment of rheumatic diseases. With the global pandemic caused by the new coronavirus, there was an increase in the prescription of these drugs, which led to a major concern regarding their ototoxic effects. Objectives The objective of the present study was to assess existing scientific evidence about the toxic effects of chloroquine and hydroxychloroquine on the peripheral and/or central auditory system. Data Synthesis A systematic literature review was performed by searching the PubMed (Medline), Scopus, Web of Science, LILACS, and SciELO electronic databases, in a search of articles that fullfiled the predefined inclusion and exclusion criteria. The review was conducted in three phases and, in all of them, analyses were performed by two independent researchers. Disagreements were discussed with a third researcher until a consensus was reached. A total of 437 articles were found and 8 were included in this review. Seven of the included studies reported hearing loss in their samples and presented a diagnostic hypothesis of ototoxicity induced by chloroquine or hydroxychloroquine. The most common type of hearing loss was sensorineural, with varying laterality and degrees of severity. The most frequently used audiological test was pure tone audiometry, and only two studies assessed brainstem evoked responses. Conclusion The scientific evidence compiled in this research showed that chloroquine and hydroxychloroquine have an ototoxic effect in the peripheral auditory system. These drugs can cause cochlear damage, including changes in the stria vascularis and lesions in sensory hair cells.

From the Ear Flap to the Nerve: A Complete Computer Model of the Peripheral Auditory System

From the Ear Flap to the Nerve: A Complete Computer Model of the Peripheral Auditory System

D-Galactose-Induced Accelerated Aging Model on Auditory Cortical Neurons by Regulating Oxidative Stress and Apoptosis in Vitro.

Age-related hearing loss (ARHL) is much more prevalent with age, affecting not only peripheral but central auditory system. We have previously established an aging model of peripheral auditory system in vitro using cultured cochlear basilar membrane. However, there is no ideal accelerated aging model on central auditory system in vitro. To establish the aging model, auditory cortical neurons (ACNs) were primary cultured and treated with either vehicle or different doses of D-galactose (D-gal). We studied the effect of D-gal on ACNs by evaluating the hallmarks of aging, including cell proliferation, oxidative stress, mitochondrial function, and neuronal apoptosis. Compared with the control group, cell viability was significantly inhibited in the D-gal-treated group in a dose-dependent manner. The production of reactive oxygen species was strongly increased in the D-gal-treated group. Meanwhile, the level of 8-hydroxy-2'-deoxyguanosine, which is a biomarker of DNA oxidative damage, was even higher in the D-gal-treated group than that in the control group. Conversely, the levels of ATP and mitochondrial membrane potential were notably decreased in the D-gal-treated group contrast to that in the control group. Furthermore, the number of neuronal apoptosis in the D-gal-treated group, compared with that in the control group, was dramatically increased in a dose-dependent approach. Together, our results demonstrate that ACNs treated with D-gal in vitro display senescence characteristics by regulating oxidative stress and apoptosis, indicating accelerated aging model on ACNs are successfully established. And the model provides a promising approach for exploring underlying mechanisms of the ARHL.

Emergence and function of cortical offset responses in sound termination detection.

Offset responses in auditory processing appear after a sound terminates. They arise in neuronal circuits within the peripheral auditory system, but their role in the central auditory system remains unknown. Here, we ask what the behavioral relevance of cortical offset responses is and what circuit mechanisms drive them. At the perceptual level, our results reveal that experimentally minimizing auditory cortical offset responses decreases the mouse performance to detect sound termination, assigning a behavioral role to offset responses. By combining in vivo electrophysiology in the auditory cortex and thalamus of awake mice, we also demonstrate that cortical offset responses are not only inherited from the periphery but also amplified and generated de novo. Finally, we show that offset responses code more than silence, including relevant changes in sound trajectories. Together, our results reveal the importance of cortical offset responses in encoding sound termination and detecting changes within temporally discontinuous sounds crucial for speech and vocalization.

Cochlear Immune Response in Presbyacusis: a Focus on Dysregulation of Macrophage Activity.

Age-related hearing loss, or presbyacusis, is a prominent chronic degenerative disorder that affects many older people. Based on presbyacusis pathology, the degeneration occurs in both sensory and non-sensory cells, along with changes in the cochlear microenvironment. The progression of age-related neurodegenerative diseases is associated with an altered microenvironment that reflects chronic inflammatory signaling. Under these conditions, resident and recruited immune cells, such as microglia/macrophages, have aberrant activity that contributes to chronic neuroinflammation and neural cell degeneration. Recently, researchers identified and characterized macrophages in human cochleae (including those from older donors). Along with the age-related changes in cochlear macrophages in animal models, these studies revealed that macrophages, an underappreciated group of immune cells, may play a critical role in maintaining the functional integrity of thecochlea. Although several studies deciphered the molecular mechanisms that regulate microglia/macrophage dysfunction in multiple neurodegenerative diseases, limited studies have assessed the mechanisms underlying macrophage dysfunction in aged cochleae. In this review, we highlight the age-related changes in cochlear macrophage activities in mouse and human temporal bones. We focus on how complement dysregulation and the nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 inflammasome could affect macrophage activity in the aged peripheral auditory system. By understanding the molecular mechanisms that underlie these regulatory systems, we may uncover therapeutic strategies to treat presbyacusis and other forms of sensorineural hearing loss.

A case series shows independent vestibular labyrinthine function after major surgical trauma to the human cochlea

BackgroundThe receptors for hearing and balance are housed together in the labyrinth of the inner ear and share the same fluids. Surgical damage to either receptor system was widely believed to cause certain permanent loss of the receptor function of the other. That principle, however, has been called into question because there have been anecdotal reports in individual patients of at least partial preservation of cochlear function after major surgical damage to the vestibular division and vice versa.MethodsWe performed specific objective vestibular function tests before and after surgical trauma (partial or subtotal cochlear removal) for treatment of intracochlear tumors in 27 consecutive patients in a tertiary referral center. Vestibular function was assessed by calorics (low-frequency response of the lateral semicircular canal), vestibulo-ocular reflex by video head impulse test (vHIT) of the three semicircular canals, cervical and ocular vestibular evoked myogenic potentials (cVEMP, saccule and oVEMP, utricle). Preoperative and postoperative distributions were compared with paired t-tests.ResultsHere we show that there was no significant difference between pre- and post-operative measures for all tests of the five vestibular organs, and that after major surgical cochlear trauma, the vestibular receptors continue to function independently.ConclusionsThese surprising observations have important implications for our understanding of the function and the surgery of the peripheral auditory and vestibular system in general and open up new possibilities for the development, construction and evaluation of neural interfaces for electrical or optical stimulation of the peripheral auditory and vestibular nervous system.

Bioinspired Auditory Model for Vowel Recognition

In this work, a bioinspired or neuromorphic model to replicate the vowel recognition process for an auditory system is presented. A bioinspired peripheral and central auditory system model is implemented and a neuromorphic higher auditory system model based on artificial neuronal nets for vowel recognition is proposed. For their verification, ten Hispanic Spanish language-speaking adults (five males and five females) were used. With the proposed bioinspired model based on artificial neuronal nets it is possible to recognize with high levels of accuracy and sensibility the vowels phonemes of speech signals and the assessment of cochlear implant stimulation strategies in terms of vowel recognition.

Functional Analyses of Peripheral Auditory System Adaptations for Echolocation in Air vs. Water

The similarity of acoustic tasks performed by odontocete (toothed whale) and microchiropteran (insectivorous bat) biosonar suggests they may have common ultrasonic signal reception and processing mechanisms. However, there are also significant media and prey dependent differences, notably speed of sound and wavelengths in air vs. water, that may be reflected in adaptations in their auditory systems and peak spectra of out-going signals for similarly sized prey. We examined the anatomy of the peripheral auditory system of two species of FM bat (big brown bat Eptesicus fuscus; Japanese house bat Pipistrellus abramus) and two toothed whales (harbor porpoise Phocoena phocoena; bottlenose dolphin Tursiops truncatus) using ultra high resolution (11–100 micron) isotropic voxel computed tomography (helical and microCT). Significant differences were found for oval and round window location, cochlear length, basilar membrane gradients, neural distributions, cochlear spiral morphometry and curvature, and basilar membrane suspension distributions. Length correlates with body mass, not hearing ranges. High and low frequency hearing range cut-offs correlate with basilar membrane thickness/width ratios and the cochlear radius of curvature. These features are predictive of high and low frequency hearing limits in all ears examined. The ears of the harbor porpoise, the highest frequency echolocator in the study, had significantly greater stiffness, higher basal basilar membrane ratios, and bilateral bony support for 60% of the basilar membrane length. The porpoise’s basilar membrane includes a “foveal” region with “stretched” frequency representation and relatively constant membrane thickness/width ratio values similar to those reported for some bat species. Both species of bats and the harbor porpoise displayed unusual stapedial input locations and low ratios of cochlear radii, specializations that may enhance higher ultrasonic frequency signal resolution and deter low frequency cochlear propagation.

INTERMITTENT TINNITUS IN ADULTS: AN INSIGHT INTO COVERT HEARING LOSS

Objectives: Association of high frequency hearing loss/minor damage in peripheral auditory system in continuous chronic tinnitus with normal PTA is well established.The purpose of the study was to verify whether this finding is true for intermittent unilateral or bilateral tinnitus patients with normal PTA using EHF audiometry and conventional DPOAEs. Materials and method:This study was conducted on 45 normal hearing adults between the age ranges of 18-30 years. Among them 30 adults comprised of study group with intermittent tinnitus which varies in laterality.Tinnitus evaluation was done on these population followed by THI administration. DPOAE and EHF audiometry was completed on all subjects after conventional hearing assessment program. Result and Discussion:Kruskal Wallis H test & Wilcoxon signed rank test was used to compare OAE amplitude & EHF thresholds.Spearman's correlation was used to evaluate the correlation between DPOAE amplitude with EHF threshold. Reduced hearing sensitivity in the extended high frequency region may be early predictor of outer hair cell dysfunction in the most basal area.Findings of this study suggest that intermittent tinnitus may also lead to subtle lesion at the basal region of cochlea which would result in a significant hearing loss with continuous tinnitus in future. Conclusion:Intermittent tinnitus may increase the fragility of peripheral auditory system which may lead to permanent lesions and would be evident as elevated thresholds in conventional PTA.

Mechanics of the Peripheral Auditory System: Foundations for Embodied Listening Using Dynamic Systems Theory and the Coupling Devices as a Metaphor.

Current approaches to listening are built on standard cognitive science, which considers the brain as the locus of all cognitive activity. This work aims to investigate listening as phenomena occurring within a brain, a body (embodiment), and an environment (situatedness). Drawing on insights from physiology, acoustics, and audiology, this essay presents listening as an interdependent brain-body-environment construct grounded in dynamic systems theory. Coupling, self-organization, and attractors are the central characteristics of dynamic systems. This article reviews the first of these aspects in order to develop a fuller understanding of how embodied auditory perception occurs. It introduces the mind-body problem before reviewing dynamic systems theory and exploring the notion of coupling in human hearing by way of current and original analogies drawn from engineering. It posits that the current use of the Watt governor device as an analogy for coupling is too simplistic to account for the coupling phenomena in the human ear. In light of this review of the physiological characteristics of the peripheral auditory system, coupling in hearing appears more variegated than originally thought and accounts for the diversity of perception among individuals, a cause for individual variance in how the mind emerges, which in turn affects academic performance. Understanding the constraints and affordances of the physical ear with regard to incoming sound supports the embodied listening paradigm.