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Holt AG, Kühl A, Braun RD, Altschuler R. The rat as a model for studying noise injury and otoprotection. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:3681. [PMID: 31795688 DOI: 10.1121/1.5131344] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A major challenge for those studying noise-induced injury pre-clinically is the selection of an animal model. Noise injury models are particularly relevant in an age when people are constantly bombarded by loud noise due to occupation and/or recreation. The rat has been widely used for noise-related morphological, physiological, biochemical, and molecular assessment. Noise exposure resulting in a temporary (TTS) or permanent threshold shift (PTS) yields trauma in peripheral and central auditory related pathways. While the precise nature of noise-related injuries continues to be delineated, both PTS and TTS (with or without hidden hearing loss) result in homeostatic changes implicated in conditions such as tinnitus and hyperacusis. Compared to mice, rats generally tolerate exposure to loud sounds reasonably well, often without exhibiting other physical non-inner ear related symptoms such as death, loss of consciousness, or seizures [Skradski, Clark, Jiang, White, Fu, and Ptacek (2001). Neuron 31, 537-544; Faingold (2002). Hear. Res. 168, 223-237; Firstova, Abaimov, Surina, Poletaeva, Fedotova, and Kovalev (2012). Bull Exp. Biol. Med. 154, 196-198; De Sarro, Russo, Citraro, and Meldrum (2017). Epilepsy Behav. 71, 165-173]. This ability of the rat to thrive following noise exposure permits study of long-term effects. Like the mouse, the rat also offers a well-characterized genome allowing genetic manipulations (i.e., knock-out, viral-based gene expression modulation, and optogenetics). Rat models of noise-related injury also provide valuable information for understanding mechanistic changes to identify therapeutic targets for treatment. This article provides a framework for selection of the rat as a model for noise injury studies.
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Affiliation(s)
- Avril Genene Holt
- Department of Ophthalmology, Visual, and Anatomical Sciences (OVAS), School of Medicine, Wayne State University, 550 East Canfield Avenue, 454 Lande Building, Detroit, Michigan 48201, USA
| | - André Kühl
- Department of Ophthalmology, Visual, and Anatomical Sciences (OVAS), School of Medicine, Wayne State University, 550 East Canfield Avenue, 454 Lande Building, Detroit, Michigan 48201, USA
| | - Rod D Braun
- Department of Ophthalmology, Visual, and Anatomical Sciences (OVAS), School of Medicine, Wayne State University, 550 East Canfield Avenue, 454 Lande Building, Detroit, Michigan 48201, USA
| | - Richard Altschuler
- Department of Otolaryngology; Cell and Developmental Biology, Kresge Hearing Research Institute, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, Michigan 48109, USA
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Landegger LD, Honeder C, Zhu C, Schöpper H, Engleder E, Gabor F, Gstoettner W, Arnoldner C. Noise trauma and systemic application of the selective glucocorticoid receptor modulator compound A. J Negat Results Biomed 2016; 15:10. [PMID: 27164957 PMCID: PMC4863352 DOI: 10.1186/s12952-016-0053-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/13/2016] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Selective glucocorticoid receptor modulators (SEGRMs) comprise a novel class of drugs promising both reduced side effects and similar pharmacological potency relative to glucocorticoids, which presently serve as the only clinical treatment for many otologic disorders. In the first otologic SEGRM experiment in an animal model of noise trauma, we compare the effects of Compound A (a SEGRM) and dexamethasone (potent glucocorticoid). METHODS Forty adult guinea pigs received experimental treatment once daily for ten days. The animals were divided into four cohorts based on the treatment received: Compound A (1 mg/kg or 3 mg/kg), dexamethasone (1 mg/kg) as gold standard, or water as negative control. After five applications, animals were exposed to broadband noise (8-16 kHz) at 115 dB for three hours. Hearing thresholds were determined by recording auditory brainstem responses to clicks and noise bursts (1-32 kHz) and were assessed a week prior to and immediately after exposure, as well as on days 1, 3, 7, 14, 21, and 28. Cochleae were prepared as whole-mounts or embedded and sectioned for histological analysis. RESULTS Relative to the control treatments, Compound A failed to preserve auditory thresholds post-noise exposure with statistical significance. Histological analyses confirm the physiological result. CONCLUSION The present findings suggest that Compound A does not have substantial otoprotective capacities in a noise trauma model.
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Affiliation(s)
- Lukas D Landegger
- Department of Otorhinolaryngology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Clemens Honeder
- Department of Otorhinolaryngology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Chengjing Zhu
- Department of Otorhinolaryngology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Hanna Schöpper
- Department of Pathobiology, Institute of Anatomy, Histology and Embryology, University of Veterinary Medicine, Veterinaerplatz 1, 1210, Vienna, Austria
| | - Elisabeth Engleder
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Franz Gabor
- Department of Pharmaceutical Technology and Biopharmaceutics, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Wolfgang Gstoettner
- Department of Otorhinolaryngology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Christoph Arnoldner
- Department of Otorhinolaryngology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Xiong M, He Q, Lai H, Wang J. Oxidative stress in spiral ganglion cells of pigmented and albino guinea pigs exposed to impulse noise. Acta Otolaryngol 2011; 131:914-20. [PMID: 21542672 DOI: 10.3109/00016489.2011.577448] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSIONS The results suggest that melanin inhibits formation of reactive oxygen species (ROS) and prevents apoptosis in spiral ganglion cells (SGCs) of pigmented guinea pigs following impulse noise. OBJECTIVE The stria vascularis of pigmented guinea pig cochlea contains melanocytes that produce melanin, which has a protective effect on noise-induced hair cell damage through its antioxidant property. ROS are involved in cochlear damage induced by impulse noise trauma. The purpose of the present study was to investigate the oxidative stress in SGCs of pigmented and albino guinea pigs after exposure to impulse noise. METHODS Pigmented and albino guinea pigs were exposed to impulse noise. Auditory thresholds were assessed by sound-evoked auditory brainstem response (ABR) before impulse noise exposure and 72 h after impulse noise exposure. 4-Hydroxynonenal (HNE) was used as a histochemical marker of ROS formation, and active-caspase-3 (cas-3) served as a marker for apoptosis. 4-HNE and cas-3 were determined immunohistochemically. Hair cell damage was analyzed by scanning electron microscopy. RESULTS The rates of 4-HNE-positive and cas-3-positive SGCs in pigmented guinea pigs were much less than those for albino guinea pigs. Correspondingly, there was less hair cell damage and reduced ABR threshold shifts in pigmented guinea pigs.
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MESH Headings
- Acoustic Stimulation/methods
- Aldehydes/metabolism
- Animals
- Apoptosis/physiology
- Brain Stem/physiopathology
- Caspase 3/metabolism
- Evoked Potentials, Auditory, Brain Stem/physiology
- Guinea Pigs
- Hair Cells, Auditory, Outer/pathology
- Hair Cells, Auditory, Outer/physiology
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Humans
- Lipid Peroxidation/physiology
- Melanins/metabolism
- Microscopy, Electron, Scanning
- Oxidative Stress/physiology
- Spiral Ganglion/pathology
- Spiral Ganglion/physiopathology
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Affiliation(s)
- Min Xiong
- Department of Otolaryngology, General Hospital of PLA Guangzhou Command, China.
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Lin FR, Thorpe R, Gordon-Salant S, Ferrucci L. Hearing loss prevalence and risk factors among older adults in the United States. J Gerontol A Biol Sci Med Sci 2011; 66:582-90. [PMID: 21357188 PMCID: PMC3074958 DOI: 10.1093/gerona/glr002] [Citation(s) in RCA: 545] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 01/03/2011] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Hearing loss has been associated with cognitive and functional decline in older adults and may be amenable to rehabilitative interventions, but national estimates of hearing loss prevalence and hearing aid use in older adults are unavailable. METHODS We analyzed data from the 2005-2006 cycle of the National Health and Nutritional Examination Survey, which is the first cycle to ever incorporate hearing assessment in adults aged 70 years and older. Audiometry was performed in 717 older adults, and data on hearing aid use, noise exposure, medical history, and demographics were obtained from interviews. Analyses incorporated sampling weights to account for the complex sampling design and yield results that are generalizable to the U.S. population. RESULTS The prevalence of hearing loss defined as a speech frequency pure tone average of more than 25 dB in the better ear was 63.1% (95% confidence interval: 57.4-68.8). Age, sex, and race were the factors most strongly associated with hearing loss after multivariate adjustment, with black race being substantially protective against hearing loss (odds ratio 0.32 compared with white participants [95% confidence interval: 0.19-0.53]). Hearing aids were used in 40.0% (95% confidence interval: 35.1-44.8) of adults with moderate hearing loss, but in only 3.4% (95% confidence interval: 0.8-6.0) of those with a mild hearing loss. CONCLUSION Hearing loss is prevalent in nearly two thirds of adults aged 70 years and older in the U.S. population. Additional research is needed to determine the epidemiological and physiological basis for the protective effect of black race against hearing loss and to determine the role of hearing aids in those with a mild hearing loss.
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Affiliation(s)
- Frank R Lin
- Department of Otolaryngology–Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
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Da Costa EA, Castro JC, Macedo MEG. Iris pigmentation and susceptibility to noise-induced hearing loss. Int J Audiol 2008; 47:115-8. [PMID: 18307091 DOI: 10.1080/14992020701704776] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The purpose of this retrospective study is to examine the possible association between iris pigmentation and susceptibility to noise-induced hearing loss in 2407 noise-exposed workers. The workers were between 16 to 65 years of age and were exposed to 2 to 42 years of work-related noise. Results demonstrated that dark-eyed workers presented a greater percentage of normal pure-tone thresholds than fair-eyed workers. Fair-eyed workers had threshold averages of 25.1 dB (right ear) and 26.0 dB (left ear) at 3, 4, and 6 kHz, which were significantly worse than workers with dark irises, with threshold averages of 15.8 dB and 17.2 dB in the right and left ear, respectively (p<0.01). Fair-eyed workers with less than 10 years of noise exposure had the same audiometric pattern as the dark-eyed workers exposed for more than 10 years. Workers not exposed to noise did not present significant differences in their audiometric pattern as a function of eye colour. These results suggest that iris pigmentation may be an additional indication of susceptibility to noise-induced hearing loss.
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Affiliation(s)
- E A Da Costa
- Department of Ophthalmo/Otolaryngology and Graduate Program in Public Health, State University of Campinas/UNICAMP, Sao Paulo, Brazil
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Dreisbach LE, Kramer SJ, Cobos S, Cowart K. Racial and gender effects on pure-tone thresholds and distortion-product otoacoustic emissions (DPOAEs) in normal-hearing young adults. Int J Audiol 2008; 46:419-26. [PMID: 17654083 DOI: 10.1080/14992020701355074] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This study examined racial and gender effects on behavioral thresholds and distortion-product otoacoustic emissions (DPOAEs) in the same subjects. Pure-tone behavioral thresholds and DPOAEs were measured in 60 young normal-hearing adult subjects (20 Caucasian, 20 Asian, 20 African-American, with ten females and ten males in each group). Behavioral thresholds were measured from 1000 through 16,000 Hz using Békèsy tracking. A DPOAE frequency sweep was measured with primary stimulus levels of L(1)/L(2)=60/45 dB SPL, and an f(2)/f(1) of 1.2 at discrete f(2) frequencies between 2000 through 12,000 Hz for each subject. Significant racial and gender differences in behavioral thresholds were found at 14,000 and 16,000 Hz, with the African Americans and females having the best hearing sensitivity. Based on the current results, similar findings for DPOAE frequency sweeps can be expected amongst different racial groups given that no significant differences were identified between the groups. To further define the effects of race and gender on auditory measures, future studies should include larger numbers of subjects, measurement of body size and middle ear reflectance, and examine emission generators.
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Affiliation(s)
- Laura E Dreisbach
- School of Speech, Language, and Hearing Sciences, San Diego State University, San Diego, California 92182-1518, USA.
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Ohlemiller KK, Lett JM, Gagnon PM. Cellular correlates of age-related endocochlear potential reduction in a mouse model. Hear Res 2006; 220:10-26. [PMID: 16901664 DOI: 10.1016/j.heares.2006.06.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 06/18/2006] [Accepted: 06/30/2006] [Indexed: 01/09/2023]
Abstract
Age-related degeneration of cochlear stria vascularis and resulting reduction in the endocochlear potential (EP) are the hallmark features of strial presbycusis, one of the major forms of presbycusis, or age-related hearing loss (ARHL) (Schuknecht, H.F., 1964. Further observations on the pathology of presbycusis. Archives of Otolaryngology 80, 369-382; Schuknecht, H.F., 1993. Pathology of the Ear. Lea and Febiger, Philadelphia; Schuknecht, H.F., Gacek, M.R., 1993. Cochlear pathology in presbycusis. Annals of Otology, Rhinology and Laryngology 102, 1-16). It is unclear whether there are multiple forms of strial ARHL having different sequences of degenerative events and different risk factors. Human temporal bone studies suggest that the initial pathology usually affects strial marginal cells, then spreads to other strial cell types. While inheritance studies support a moderate genetic influence, no contributing genes have been identified. Establishment of mouse models of strial ARHL may promote the identification of underlying genes and gene/environment interactions. We have found that BALB/cJ mice show significant EP reduction by 19 months of age. The reduction only occurs in a subset of animals. To identify key anatomical correlates of the EP reduction, we compared several cochlear lateral wall metrics in BALBs with those in C57BL/6J (B6) mice, which show little EP reduction for ages up to 26 months. Among the measures obtained, marginal cell density and spiral ligament thickness were the best predictors of both the EP decline in BALBs, and EP stability in B6. Our results indicate that the sequence of strial degeneration in BALBs is like that suggested for humans. Additional strain comparisons we have performed suggest that genes governing strial melanin production do not play a role.
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Affiliation(s)
- Kevin K Ohlemiller
- Department of Otolaryngology, Washington University School of Medicine, 660 S. Euclid, Saint Louis, MO 63110, USA.
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Hayashi H, Sone M, Ito S, Wakamatsu K, Kato M, Nakashima I, Nakashima T. A novel RFP-RET transgenic mouse model with abundant eumelanin in the cochlea. Hear Res 2005; 195:35-40. [PMID: 15350277 DOI: 10.1016/j.heares.2004.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2003] [Accepted: 01/21/2004] [Indexed: 11/22/2022]
Abstract
We report on the cochlea of a novel metallothionein-I (MT)/RFP-RET transgenic mouse model with severe systemic melanosis. Electron microscopy revealed that these transgenic mice possess abundant quantities of melanin in the intermediate cells of the stria vascularis. High performance liquid chromatography analysis indicated that cochleae of these transgenic mice contained about twice as much eumelanin as cochleae of control C57BL/6 mice and that the amount of pheomelanin was approximately equal in these two strains. Auditory brainstem responses at 2, 4, 8, and 16 kHz were not significantly different between transgenic and control mice. This is the first report on a mouse model of overproduction of cochlear eumelanin, and our results suggest that this transgenic mouse is an excellent model for investigating the effects of overexpression of cochlear eumelanin. In addition, we provide evidence that eumelanin overproduction in the cochlea does not affect normal hearing.
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Affiliation(s)
- Hideo Hayashi
- Department of Otorhinolaryngology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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Abstract
Fischer 344 (F344) rats are often used as an animal model for investigation of the mechanisms underlying age-related hearing loss. The aim of this study was to assess cochlear function in young (1-month-old) and adult (6-month-old) F344 rats using recording of otoacoustic emissions and auditory brainstem responses (ABRs). The results were compared with control groups of Long Evans (LE) rats of the same ages. The results demonstrate a significant increase in the hearing threshold in F344 rats in comparison with LE rats, expressed mainly at low frequencies (1-2 kHz). In F344 rats, transient evoked otoacoustic emissions were not measurable and distortion product otoacoustic emissions could be detected within a frequency range of 2.4-6.3 kHz. Tympanometric measurements did not reveal any differences in middle ear parameters between F344 and LE rats. The amplitudes of click-evoked ABRs were significantly lower in 6-month-old F344 rats than in LE rats, but other parameters of the ABRs were almost identical in both rat strains. The results demonstrate a significant deficit in low-frequency hearing and altered otoacoustic emissions in both young and adult F344 rats, suggesting a defect of the inner ear sensory epithelium at the apical part of the cochlea.
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Affiliation(s)
- Jiri Popelar
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
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10
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Abstract
Conflicting investigations regarding the potential protective effect of melanin against noise-induced sensorineural hearing loss have suggested that eumelanin and pheomelanin may have differing effects within the stria vascularis. Three strains of C57BL/6J mice, (+/+, a/a) wild-types (dark coats/black eyes), (c2j/c2j, a/a), albinos (white coats/pink eyes), and (+/+, Ay/Ay) yellow mice (yellow coats/black eyes), were subjected to five consecutive days of broad band noise exposure at 112 dB(A) SPL for 3 h/day. Cochlear function was evaluated with auditory brainstem response audiometry to pure tones immediately pre-exposure, 5-6 h postexposure, and 14 days post-exposure. No significant difference in the degree of sensorineural hearing loss induced in the three strains of mice was identified. The eumelanin and pheomelanin content of each stria vascularis and amount of protein per stria for both mouse and guinea pig (2/NCR) were determined via high performance liquid chromatography. No pheomelanin was found in the stria of yellow mice, suggesting that coat color is not an accurate predictor of strial melanin content. The melanin content per mg of strial protein was higher in mice than in guinea pigs. A species-specific difference in melanin content does not explain the absence of a protective effect in mice.
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Affiliation(s)
- S Bartels
- Department of Otolaryngology/Head and Neck Surgery, Oregon Hearing Research Center, Oregon Health Sciences University, Portland 97201-3098, USA
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Ohlemiller KK, Wright JS, Heidbreder AF. Vulnerability to noise-induced hearing loss in 'middle-aged' and young adult mice: a dose-response approach in CBA, C57BL, and BALB inbred strains. Hear Res 2000; 149:239-47. [PMID: 11033262 DOI: 10.1016/s0378-5955(00)00191-x] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Vulnerability of the cochlea to noise-induced permanent threshold shifts (NIPTS) was examined in young adult (1-2 months) and 'middle-aged' (5-7 months) CBA/CaJ, C57BL/6J, and BALB/cJ inbred mice. For each age and strain, a dose-response paradigm was applied, whereby groups of up to 12 animals were exposed to intense broadband noise (110 dB SPL) for varying durations. Exposure durations reliably associated with <10% and >90% probability of a criterion amount of NIPTS (determined 2 weeks post-exposure) were identified, and the minimum NIPTS exposure and the slope of the dose-response relation were then derived by numerical modeling. For all three strains, young adult mice were more susceptible to NIPTS than older adults; That is, a shorter exposure was able to cause NIPTS in the younger mice. Strain comparisons revealed that C57 mice were more susceptible than CBAs in the older age group only. At both ages examined, however, BALB mice were most susceptible to NIPTS. When animals with a similar amount of NIPTS were compared, outer hair cell loss in the cochlear base was more widespread in the younger animals. BALB mice appear particularly susceptible to noise-induced outer hair cell loss throughout life. Our data suggest that the mechanism or site of noise injury differs between young adults and older adults, and may depend on genetic background. The finding that both BALB and C57 mice, which show pronounced age-related hearing loss, are also especially vulnerable to noise supports the notion that genes associated with age-related hearing loss often act by rendering the cochlea susceptible to insults.
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Affiliation(s)
- K K Ohlemiller
- Fay and Carl Simons Center for the Biology of Hearing and Deafness, Central Institute for the Deaf, 818 S. Euclid Av., St. Louis, MO 63110, USA.
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Barrenas ML. Hair Cell Loss from Acoustic Trauma in Chloroquine-treated Red, Black and Albino Guinea Pigs. Int J Audiol 1997. [DOI: 10.3109/00206099709071973] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Parving A, Hein HO, Suadicani P, Ostri B, Gyntelberg F. Epidemiology of hearing disorders. Some factors affecting hearing. The Copenhagen Male Study. SCANDINAVIAN AUDIOLOGY 1993; 22:101-7. [PMID: 8321994 DOI: 10.3109/01050399309046025] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This epidemiological investigation reports on the results from a 10-year follow-up examination concerning hearing and factors known to cause hearing problems. In addition, an evaluation concerning the possible association between hearing impairment and factors affecting the state of health is reported. The original sample comprised 5,050 subjects, and at the present examination 3,387 (67%) males at a median age of 63 years (range 53-75) participated. An increasing prevalence of 30-40% of hearing problems was demonstrated with increasing age. A prevalence of 17% of tinnitus of more than 5 min duration was found; 3% indicated that their tinnitus was so annoying that it interfered with sleep, reading and/or concentration. The prevalence of tinnitus increased up to the age of 70, and seemed to remain constant thereafter. A significant correlation between experienced hearing problems and environmental factors causing damage to the hearing organ was found. Furthermore, a correlation between hearing problems and C3-S complement was found, but no correlations could be established between hearing problems and other blood groups. No correlation was found between cardiovascular disease and hearing problems except for minor circulatory problems, nor between hearing problems and hormonal diseases. It is concluded that the present study supports previous epidemiological investigations concerning the prevalence of hearing problems and factors affecting hearing. The association between hearing problems and C3-S complement, which to the authors' knowledge has not previously been reported, should be further evaluated. No association was found between hearing problems and other blood groups.
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Affiliation(s)
- A Parving
- Department of Audiology, Bispebjerg Hospital, Copenhagen, Denmark
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Whitehead ML, Kamal N, Lonsbury-Martin BL, Martin GK. Spontaneous otoacoustic emissions in different racial groups. SCANDINAVIAN AUDIOLOGY 1993; 22:3-10. [PMID: 8465138 DOI: 10.3109/01050399309046012] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To determine if there are racial differences in the prevalence of spontaneous otoacoustic emissions (SOAEs), both ears of 20 Negro, 20 Asian and 20 Caucasian subjects were examined for the presence of SOAEs. Within each racial group, equal numbers of normally hearing males and females were tested. Significant differences in the occurrence of SOAEs were found between the three racial groups, with Negroes expressing more SOAEs than Caucasians, and Asians demonstrating an intermediate number of these emissions. In support of previous observations, more emissions were recorded from female than from male ears, and a significant correlation of the number of emissions in the two ears of an individual was also noted.
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Affiliation(s)
- M L Whitehead
- Department of Otolaryngology, University of Miami Ear Institute, Florida
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Abstract
Animals with various degrees of inbreeding, some of which are albino, are frequently used in biological research. Albinos do not produce melanin and it is therefore absent from the cochlea. While the function of melanin is unknown, it has been hypothesized that it is involved in cochlear homeostasis. It is possible then, that age-related degeneration may be affected by the presence or absence of melanin. We therefore evaluated young (2-6 months old) and aged (24-36 months old) cochleas in 4 different rat strains: albino Fischer 344 and Lewis rats and pigmented Lewis-Brown Norway F1 rats and Brown Norway rats. Cochlear morphology was the same across all strains of young adult animals with the exception that the pigmented animals had small, darkly stained granules in the stria vascularis. The aged pigmented animals all had large granules as well as small ones. Degeneration of spiral ganglion cells in the apical region of the ganglion had occurred in the old animals of all strains. Strial degeneration at the apex was also present in aged animals. There was no correlation between the presence or absence of melanin and the magnitude of cochlear degenerative changes in the aged animals. The presence or absence of melanin therefore, appears to have no effect on cochlear degeneration in the aged rat cochlea.
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Affiliation(s)
- E M Keithley
- Department of Surgery, University of California, San Diego, La Jolla 92093-0666
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Barrenäs ML, Lindgren F. The influence of inner ear melanin on susceptibility to TTS in humans. SCANDINAVIAN AUDIOLOGY 1990; 19:97-102. [PMID: 2371541 DOI: 10.3109/01050399009070759] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In order to investigate the function of the inner ear melanin, the relationship between skin pigmentation and noise-induced temporary hearing loss (TTS) was studied. Forty-four normal-hearing Caucasian subjects were divided into three groups according to their sun sensitivity. Hearing thresholds before and after exposure were ascertained with a computerized sweep frequency audiometer in the frequency range 2-8 kHz. The noise exposure consisted of a 1/3-octave band-filtered noise with a centre frequency of 2 kHz at 105 dB SPL for 10 min. The mean TTS in the frequency range 2-8 kHz showed statistically significant differences between the three groups, i.e. the most pigmented subjects developed least TTS, and the least pigmented subjects most TTS.
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Affiliation(s)
- M L Barrenäs
- Department of Audiology, Sahlgrenska Sjukhuset, Göteborg, Sweden
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Grenner J, Nilsson P, Katbamna B. Right-left correlation in guinea pig ears after noise exposure. Acta Otolaryngol 1990; 109:41-8. [PMID: 2309558 DOI: 10.3109/00016489009107413] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In order to investigate whether experimental material consisting of noise-exposed animals should be regarded as 'ears' or 'animals', a comparison was made between the permanent threshold shifts in the right and left ears in 53 groups of noise-exposed guinea-pigs, with 5 animals in each group. The action potential (N1) thresholds were measured at fourteen frequencies in both ears. In the noise-exposed animals, the threshold elevations were up to 40 dB. The average right-left correlation coefficient within each group was about 0.79, regardless of noise energy. The degree of correlation was significantly greater after impact noise than after continuous noise. As a consequence of the high right-left correlation, the informative value of measuring a second ear in the same animal was, in our experiments, only 11% of that of the first one. No correlation could be found between the degree of skin pigmentation and the threshold elevation.
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Affiliation(s)
- J Grenner
- Department of Otolaryngology, Malmö General Hospital, University of Lund, Sweden
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