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Stahl AN, Mondul JA, Alek KA, Hackett TA, Ramachandran R. Audiologic characterization using clinical physiological measures: Normative data from macaque monkeys. Hear Res 2022; 424:108568. [PMID: 35896044 PMCID: PMC9529828 DOI: 10.1016/j.heares.2022.108568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 06/28/2022] [Accepted: 07/08/2022] [Indexed: 12/16/2022]
Abstract
Clinical auditory physiological measures (e.g., auditory brainstem responses, ABRs, and distortion product otoacoustic emissions, DPOAEs) provide diagnostic specificity for differentially diagnosing overt hearing impairments, but they remain limited in their ability to detect specific sites of lesion and subtle levels of cochlear damage. Studies in animal models may hold the key to improve differential diagnosis due to the ability to induce tightly controlled and histologically verifiable subclinical cochlear pathologies. Here, we present a normative set of traditional and clinically novel physiological measures using ABRs and DPOAEs measured in a large cohort of male macaque monkeys. Given the high similarities between macaque and human auditory anatomy, physiology, and susceptibility to hearing damage, this normative data set will serve as a crucial baseline to investigate novel physiological measures to improve diagnostics. DPOAE amplitudes were robust at f2 = 1.22, L1/L2 = 65/55, increased with frequency up to 10 kHz, and exhibited high test re-test reliability. DPOAE thresholds were lowest from 2-10 kHz and highest < 2 kHz. ABRs with a standard clinical electrode montage (vertex-to-mastoid, VM) produced Waves I-IV with a less frequently observed Wave-I, and lower thresholds. ABRs with a vertex-to-tympanic membrane (VT) electrode montage produced a more robust Wave-I, but absent Waves II-IV and higher thresholds. Further study with the VM montage revealed amplitudes that increased with stimulus level and were largest in response to click stimuli, with Wave-II showing the largest ABR amplitude, followed by -IV and -I, with high inter- and intra-subject variability. ABR wave latencies decreased with stimulus level and frequency. When stimulus presentation rate increased or stimuli were presented in close temporal proximity, ABR amplitude decreased, and latency increased. These findings expand upon existing literature of normative clinical physiological data in nonhuman primates and lay the groundwork for future studies investigating the effects of noise-induced pathologies in macaques.
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Affiliation(s)
- Amy N Stahl
- Vanderbilt Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37212; Vanderbilt Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37212.
| | - Jane A Mondul
- Vanderbilt Neuroscience Graduate Program, Vanderbilt University, Nashville, TN 37212; Vanderbilt Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37212.
| | - Katy A Alek
- Vanderbilt Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37212.
| | - Troy A Hackett
- Vanderbilt Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37212.
| | - Ramnarayan Ramachandran
- Vanderbilt Department of Hearing and Speech Sciences, Vanderbilt University Medical Center, Nashville, TN 37212.
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Pyott SJ, van Tuinen M, Screven LA, Schrode KM, Bai JP, Barone CM, Price SD, Lysakowski A, Sanderford M, Kumar S, Santos-Sacchi J, Lauer AM, Park TJ. Functional, Morphological, and Evolutionary Characterization of Hearing in Subterranean, Eusocial African Mole-Rats. Curr Biol 2020; 30:4329-4341.e4. [PMID: 32888484 DOI: 10.1016/j.cub.2020.08.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/09/2020] [Accepted: 08/07/2020] [Indexed: 12/26/2022]
Abstract
Naked mole-rats are highly vocal, eusocial, subterranean rodents with, counterintuitively, poor hearing. The causes underlying their altered hearing are unknown. Moreover, whether altered hearing is degenerate or adaptive to their unique lifestyles is controversial. We used various methods to identify the factors contributing to altered hearing in naked and the related Damaraland mole-rats and to examine whether these alterations result from relaxed or adaptive selection. Remarkably, we found that cochlear amplification was absent from both species despite normal prestin function in outer hair cells isolated from naked mole-rats. Instead, loss of cochlear amplification appears to result from abnormal hair bundle morphologies observed in both species. By exploiting a well-curated deafness phenotype-genotype database, we identified amino acid substitutions consistent with abnormal hair bundle morphology and reduced hearing sensitivity. Amino acid substitutions were found in unique groups of six hair bundle link proteins. Molecular evolutionary analyses revealed shifts in selection pressure at both the gene and the codon level for five of these six hair bundle link proteins. Substitutions in three of these proteins are associated exclusively with altered hearing. Altogether, our findings identify the likely mechanism of altered hearing in African mole-rats, making them the only identified mammals naturally lacking cochlear amplification. Moreover, our findings suggest that altered hearing in African mole-rats is adaptive, perhaps tailoring hearing to eusocial and subterranean lifestyles. Finally, our work reveals multiple, unique evolutionary trajectories in African mole-rat hearing and establishes species members as naturally occurring disease models to investigate human hearing loss.
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Affiliation(s)
- Sonja J Pyott
- University Medical Center Groningen and University of Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713GZ Groningen, the Netherlands.
| | - Marcel van Tuinen
- University Medical Center Groningen and University of Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713GZ Groningen, the Netherlands
| | - Laurel A Screven
- Johns Hopkins School of Medicine, Department of Otolaryngology, Baltimore, MD 21205, USA
| | - Katrina M Schrode
- Johns Hopkins School of Medicine, Department of Otolaryngology, Baltimore, MD 21205, USA
| | - Jun-Ping Bai
- Yale University School of Medicine, Department of Neurology, 333 Cedar Street, New Haven, CT 06510, USA
| | - Catherine M Barone
- University of Illinois at Chicago, Department of Biological Sciences, Chicago, IL 60612, USA
| | - Steven D Price
- University of Illinois at Chicago, Department of Anatomy and Cell Biology, Chicago, IL 60612, USA
| | - Anna Lysakowski
- University of Illinois at Chicago, Department of Anatomy and Cell Biology, Chicago, IL 60612, USA
| | - Maxwell Sanderford
- Temple University, Institute for Genomics and Evolutionary Medicine and Department of Biology, Philadelphia, PA 19122, USA
| | - Sudhir Kumar
- Temple University, Institute for Genomics and Evolutionary Medicine and Department of Biology, Philadelphia, PA 19122, USA; King Abdulaziz University, Center for Excellence in Genome Medicine and Research, Jeddah, Saudi Arabia
| | - Joseph Santos-Sacchi
- Yale University School of Medicine, Department of Surgery (Otolaryngology) and Department of Neuroscience and Cellular and Molecular Physiology, 333 Cedar Street, New Haven, CT 06510, USA
| | - Amanda M Lauer
- Johns Hopkins School of Medicine, Department of Otolaryngology, Baltimore, MD 21205, USA
| | - Thomas J Park
- University of Illinois at Chicago, Department of Biological Sciences, Chicago, IL 60612, USA
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Nengovhela A, Braga J, Denys C, de Beer F, Tenailleau C, Taylor PJ. Associated tympanic bullar and cochlear hypertrophy define adaptations to true deserts in African gerbils and laminate-toothed rats (Muridae: Gerbillinae and Murinae). J Anat 2019; 234:179-192. [PMID: 30474264 PMCID: PMC6326829 DOI: 10.1111/joa.12906] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2018] [Indexed: 10/27/2022] Open
Abstract
Hearing capabilities in desert rodents such as gerbils and heteromyids have been inferred from both anatomical and ecological aspects and tested with experiments and theoretical models. However, very few studies have focused on other desert-adapted species. In this study, a refined three-dimensional morphometric approach was used on three African rodent tribes (Otomyini, Taterillini and Gerbillini) to describe the cochlear and tympanic bullar morphology, and to explore the role of phylogeny, allometry and ecology to better understand the underlying mechanism of any observed trends of hypertrophy in the bulla and associated changes in the cochlea. As a result, desert-adapted species could be distinguished from mesic and semi-arid taxa by the gross cochlear dimensions, particularly the oval window, which is larger in desert species. Bullar and cochlear modifications between species could be explained by environment (bulla and oval window), phylogeny (cochlear curvature gradient) and/or allometry (cochlear relative length, oval window and bulla) with some exceptions. Based on their ear anatomy, we predict that Desmodillus auricularis and Parotomys brantsii should be sensitive to low-frequency sounds, with D. auricularis sensitive to high-frequency sounds, too. This study concludes that in both arid and semi-arid adapted laminate-toothed rats and gerbils there is bulla and associated cochlea hypertrophy, particularly in true desert species. Gerbils also show tightly coiled cochlea but the significance of this is debatable and may have nothing to do with adaptations to any specific acoustics in the desert environment.
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Affiliation(s)
- Aluwani Nengovhela
- Laboratoire d'Anthropologie Moléculaire et Imagerie de SynthèseUMR 5288CNRSUniversité de Toulouse (Paul Sabatier)ToulouseFrance
- South African Research Chair in Biodiversity and Change and Centre for Invasion BiologySchool of Mathematical and Natural SciencesUniversity of VendaThohoyandouSouth Africa
| | - José Braga
- Laboratoire d'Anthropologie Moléculaire et Imagerie de SynthèseUMR 5288CNRSUniversité de Toulouse (Paul Sabatier)ToulouseFrance
- Evolutionary Studies InstituteUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Christiane Denys
- Institut de Systématique, Evolution, BiodiversitéUMR 7205, CNRS, MNHN, UPMC, EPHESorbonne UniversitésParisFrance
| | - Frikkie de Beer
- South African Nuclear Energy CorporationPelindabaNorth West ProvinceSouth Africa
| | - Christophe Tenailleau
- Centre Inter‐Universitaire de Recherche et d'Ingénierie des MatériauxUMR 5085CNRSUniversité de Toulouse (Paul Sabatier)ToulouseFrance
| | - Peter J. Taylor
- South African Research Chair in Biodiversity and Change and Centre for Invasion BiologySchool of Mathematical and Natural SciencesUniversity of VendaThohoyandouSouth Africa
- Core Team Member of the Centre of Invasion BiologyStellenbosch UniversityStellenboschSouth Africa
- School of Life SciencesUniversity of KwaZulu‐NatalDurbanSouth Africa
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Mason MJ. Structure and function of the mammalian middle ear. I: Large middle ears in small desert mammals. J Anat 2015; 228:284-99. [PMID: 26104342 DOI: 10.1111/joa.12313] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2015] [Indexed: 11/26/2022] Open
Abstract
Many species of small desert mammals are known to have expanded auditory bullae. The ears of gerbils and heteromyids have been well described, but much less is known about the middle ear anatomy of other desert mammals. In this study, the middle ears of three gerbils (Meriones, Desmodillus and Gerbillurus), two jerboas (Jaculus) and two sengis (elephant-shrews: Macroscelides and Elephantulus) were examined and compared, using micro-computed tomography and light microscopy. Middle ear cavity expansion has occurred in members of all three groups, apparently in association with an essentially 'freely mobile' ossicular morphology and the development of bony tubes for the middle ear arteries. Cavity expansion can occur in different ways, resulting in different subcavity patterns even between different species of gerbils. Having enlarged middle ear cavities aids low-frequency audition, and several adaptive advantages of low-frequency hearing to small desert mammals have been proposed. However, while Macroscelides was found here to have middle ear cavities so large that together they exceed brain volume, the bullae of Elephantulus are considerably smaller. Why middle ear cavities are enlarged in some desert species but not others remains unclear, but it may relate to microhabitat.
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Affiliation(s)
- Matthew J Mason
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
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