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Hutchison P, Maeda H, Formby C, Small BJ, Eddins DA, Eddins AC. Acoustic deprivation modulates central gain in human auditory brainstem and cortex. Hear Res 2023; 428:108683. [PMID: 36599259 PMCID: PMC9872081 DOI: 10.1016/j.heares.2022.108683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 12/16/2022] [Accepted: 12/26/2022] [Indexed: 12/28/2022]
Abstract
Beyond reduced audibility, there is convincing evidence that the auditory system adapts according to the principles of homeostatic plasticity in response to a hearing loss. Such compensatory changes include modulation of central auditory gain mechanisms. Earplugging is a common experimental method that has been used to introduce a temporary, reversible hearing loss that induces changes consistent with central gain modulation. In the present study, young, normal-hearing adult participants wore a unilateral earplug for two weeks, during which we measured changes in the acoustic reflex threshold (ART), loudness perception, and cortically-evoked (40 Hz) auditory steady-state response (ASSR) to assess potential modulation in central gain with reduced peripheral input. The ART decreased on average by 8 to 10 dB during the treatment period, with modest increases in loudness perception after one week but not after two weeks of earplug use. Significant changes in both the magnitude and hemispheric laterality of source-localized cortical ASSR measures revealed asymmetrical changes in stimulus-driven cortical activity over time. The ART results following unilateral earplugging are consistent with the literature and suggest that homeostatic plasticity is evident in the brainstem. The novel findings from the cortical ASSR in the present study indicates that reduced peripheral input induces adaptive homeostatic plasticity reflected as both an increase in central gain in the auditory brainstem and reduced cortical activity ipsilateral to the deprived ear. Both the ART and the novel use of the 40-Hz ASSR provide sensitive measures of central gain modulation in the brainstem and cortex of young, normal hearing listeners, and thus may be useful in future studies with other clinical populations.
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Affiliation(s)
- Peter Hutchison
- Department of Communication Sciences and Disorders, University of South Florida, 4202 E. Fowler Ave., PCD 1017, Tampa, FL 33620, USA
| | - Hannah Maeda
- Department of Communication Sciences and Disorders, University of South Florida, 4202 E. Fowler Ave., PCD 1017, Tampa, FL 33620, USA
| | - Craig Formby
- Department of Communication Sciences and Disorders, University of South Florida, 4202 E. Fowler Ave., PCD 1017, Tampa, FL 33620, USA
| | - Brent J Small
- School of Aging Studies, University of South Florida, 4202 E. Fowler Ave., PCD 1017, Tampa, FL 33620, USA
| | - David A Eddins
- Department of Communication Sciences and Disorders, University of South Florida, 4202 E. Fowler Ave., PCD 1017, Tampa, FL 33620, USA; Department of Chemical and Biomedical Engineering, University of South Florida, 4202 E. Fowler Ave., PCD 1017, Tampa, FL 33620, USA
| | - Ann Clock Eddins
- Department of Communication Sciences and Disorders, University of South Florida, 4202 E. Fowler Ave., PCD 1017, Tampa, FL 33620, USA; School of Communication Sciences and Disorders, University of Central Florida, 4364 Scorpius Street, Orlando, FL 32816, USA.
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Henry JA. Sound Therapy to Reduce Auditory Gain for Hyperacusis and Tinnitus. Am J Audiol 2022; 31:1067-1077. [DOI: 10.1044/2022_aja-22-00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Purpose:
Hyperacusis is the most common of the different types of sound tolerance conditions. It has been defined as physical discomfort or pain when any sound reaches a certain level of loudness that would be comfortable for most people. Because hyperacusis and tinnitus occur together so often, it has been theorized that they have a common neural mechanism. A leading contender for that mechanism is enhancement of auditory gain. The purpose of this tutorial is to review the evidence that sound/acoustic therapy can reduce auditory gain and, thereby, can increase loudness tolerance for people with hyperacusis and/or suppress the percept of tinnitus.
Method:
The scientific literature was informally reviewed to identify and elucidate relationships between tinnitus, hyperacusis, sound therapy, and auditory gain.
Results:
Evidence exists, both in animal and human studies, that enhanced auditory gain is associated with hyperacusis and tinnitus. Further evidence supports the theory that certain forms of sound therapy can reduce neural hyperactivity, thereby reducing auditory gain. The evidence for sound therapy reducing auditory gain is stronger for hyperacusis than it is for tinnitus.
Conclusions:
Based on results from numerous studies, sound therapy clearly has application as a method of desensitization for hyperacusis. Enhanced auditory gain might be responsible for tinnitus, but other mechanisms have been theorized. A review of the relevant literature leads to the conclusion that some form(s) of sound therapy has the potential to suppress or eliminate tinnitus on a long-term basis. Systematic research is needed to evaluate this premise.
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Affiliation(s)
- James A. Henry
- VA RR&D National Center for Rehabilitative Auditory Research, VA Portland Health Care System, OR
- Department of Otolaryngology - Head and Neck Surgery, Oregon Health & Science University, Portland
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Sheppard A, Stocking C, Ralli M, Salvi R. A review of auditory gain, low-level noise and sound therapy for tinnitus and hyperacusis. Int J Audiol 2019; 59:5-15. [DOI: 10.1080/14992027.2019.1660812] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Adam Sheppard
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
| | - Christina Stocking
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
| | - Massimo Ralli
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
- Department of Oral and Maxillofacial Sciences, Sapienza University of Rome, Rome, Italy
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, USA
- Department of Communicative Disorders and Sciences, University at Buffalo, Buffalo, NY, USA
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4
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Favaretto N, Marioni G, Brotto D, Sorrentino F, Gheller F, Castiglione A, Montino S, Giacomelli L, Trevisi P, Martini A, Bovo R. Cochlear implant outcomes in the elderly: a uni- and multivariate analyses of prognostic factors. Eur Arch Otorhinolaryngol 2019; 276:3089-3094. [DOI: 10.1007/s00405-019-05613-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 08/21/2019] [Indexed: 12/01/2022]
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Effects of Amplification and Hearing Aid Experience on the Contribution of Specific Frequency Bands to Loudness. Ear Hear 2019; 40:143-155. [PMID: 29794566 DOI: 10.1097/aud.0000000000000603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The primary aim of this study is to describe the effect of hearing aid amplification on the contribution of specific frequency bands to overall loudness in adult listeners with sensorineural hearing loss (SNHL). Results for listeners with SNHL were compared with results for listeners with normal hearing (NH) to evaluate whether amplification restores the normal perception of loudness for broadband sound. A secondary aim of this study is to determine whether the loudness perception of new hearing aid users becomes closer to normal over the first few months of hearing aid use. It was hypothesized that amplification would cause the high-frequency bands to contribute most to the perception of loudness and that this effect might decrease as new hearing aid users adapt to amplification. DESIGN In experiment 1, 8 adult listeners with SNHL completed a two-interval forced-choice loudness task in unaided and aided conditions. A control group of 7 listeners with NH completed the task in the unaided condition only. Stimuli were composed of seven summed noise bands whose levels were independently adjusted between presentations. During a trial, two stimuli were presented, and listeners determined the louder one. The correlation between the difference in levels for a given noise band on every trial and the listener's response was calculated. The resulting measure is termed the perceptual weight because it provides an estimate of the relative contribution of a given frequency region to overall loudness. In experiment 2, a separate group of 6 new hearing aid users repeated identical procedures on 2 sessions separated by 12 weeks. RESULTS Results for listeners with SNHL were similar in experiments 1 and 2. In the unaided condition, perceptual weights were greatest for the low-frequency bands. In the aided condition, perceptual weights were greatest for the high-frequency bands. On average, the aided perceptual weights for listeners with SNHL for high-frequency bands were greater than the unaided weights for listeners with NH. In experiment 2, hearing aid experience did not have a significant effect on perceptual weights. CONCLUSIONS The high frequencies seem to dominate loudness perception in listeners with SNHL using hearing aids as they do in listeners with NH. However, the results suggest that amplification causes high frequencies to have a larger contribution to overall loudness compared with listeners with NH. The contribution of the high frequencies to loudness did not change after an acclimatization period for the first-time hearing aid users.
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Cheung SW, Atencio CA, Levy ERJ, Froemke RC, Schreiner CE. Anisomorphic cortical reorganization in asymmetric sensorineural hearing loss. J Neurophysiol 2017; 118:932-948. [PMID: 28515283 DOI: 10.1152/jn.00119.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 11/22/2022] Open
Abstract
Acoustic trauma or inner ear disease may predominantly injure one ear, causing asymmetric sensorineural hearing loss (SNHL). While characteristic frequency (CF) map plasticity of primary auditory cortex (AI) contralateral to the injured ear has been detailed, there is no study that also evaluates ipsilateral AI to compare cortical reorganization across both hemispheres. We assess whether the normal isomorphic mirror-image relationship between the two hemispheres is maintained or disrupted in mild-to-moderate asymmetric SNHL of adult squirrel monkeys. At week 24 after induction of acoustic injury to the right ear, functional organization of the two hemispheres differs in direction and magnitude of interaural CF difference, percentage of recording sites with spectrally nonoverlapping binaural activation, and the concurrence of peripheral and central activation thresholds. The emergence of this anisomorphic cortical reorganization of the two hemispheres is replicated by simulation based on spike timing-dependent plasticity, where 1) AI input from the contralateral ear is dominant, 2) reestablishment of relatively shorter contralateral ear input timing drives reorganization, and 3) only AI contralateral to the injured ear undergoes major realignment of interaural frequency maps that evolve over months. Asymmetric SNHL disrupts isomorphic organization between the two hemispheres and results in relative local hemispheric autonomy, potentially impairing performance of tasks that require binaural input alignment or interhemispheric processing.NEW & NOTEWORTHY Mild-to-moderate hearing loss in one ear and essentially normal hearing in the other triggers cortical reorganization that is different in the two hemispheres. Asymmetry of cochlea sensitivities does not simply propagate to the two auditory cortices in mirror-image fashion. The resulting anisomorphic cortical reorganization may be a neurophysiological basis of clinical deficits in asymmetric hearing loss, such as difficulty with hearing in noise, impaired spatial hearing, and accelerated decline of the poorer ear.
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Affiliation(s)
- Steven W Cheung
- Coleman Memorial Laboratory and UCSF Center for Integrative Neuroscience, Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, California; .,Section of Otorhinolaryngology (112B), Surgical Services, Department of Veterans Affairs Medical Center, San Francisco, California
| | - Craig A Atencio
- Coleman Memorial Laboratory and UCSF Center for Integrative Neuroscience, Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, California
| | - Eliott R J Levy
- Center for Neural Science, New York University, New York, New York; and
| | - Robert C Froemke
- Center for Neural Science, New York University, New York, New York; and.,Skirball Institute, Neuroscience Institute, Department of Otolaryngology, and Department of Neuroscience and Physiology, New York University School of Medicine, New York, New York
| | - Christoph E Schreiner
- Coleman Memorial Laboratory and UCSF Center for Integrative Neuroscience, Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, California
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Gieseler A, Tahden MAS, Thiel CM, Wagener KC, Meis M, Colonius H. Auditory and Non-Auditory Contributions for Unaided Speech Recognition in Noise as a Function of Hearing Aid Use. Front Psychol 2017; 8:219. [PMID: 28270784 PMCID: PMC5318449 DOI: 10.3389/fpsyg.2017.00219] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 02/06/2017] [Indexed: 11/13/2022] Open
Abstract
Differences in understanding speech in noise among hearing-impaired individuals cannot be explained entirely by hearing thresholds alone, suggesting the contribution of other factors beyond standard auditory ones as derived from the audiogram. This paper reports two analyses addressing individual differences in the explanation of unaided speech-in-noise performance among n = 438 elderly hearing-impaired listeners (mean = 71.1 ± 5.8 years). The main analysis was designed to identify clinically relevant auditory and non-auditory measures for speech-in-noise prediction using auditory (audiogram, categorical loudness scaling) and cognitive tests (verbal-intelligence test, screening test of dementia), as well as questionnaires assessing various self-reported measures (health status, socio-economic status, and subjective hearing problems). Using stepwise linear regression analysis, 62% of the variance in unaided speech-in-noise performance was explained, with measures Pure-tone average (PTA), Age, and Verbal intelligence emerging as the three most important predictors. In the complementary analysis, those individuals with the same hearing loss profile were separated into hearing aid users (HAU) and non-users (NU), and were then compared regarding potential differences in the test measures and in explaining unaided speech-in-noise recognition. The groupwise comparisons revealed significant differences in auditory measures and self-reported subjective hearing problems, while no differences in the cognitive domain were found. Furthermore, groupwise regression analyses revealed that Verbal intelligence had a predictive value in both groups, whereas Age and PTA only emerged significant in the group of hearing aid NU.
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Affiliation(s)
- Anja Gieseler
- Cluster of Excellence 'Hearing4all', University of OldenburgOldenburg, Germany; Cognitive Psychology Lab, Department of Psychology, University of OldenburgOldenburg, Germany
| | - Maike A S Tahden
- Cluster of Excellence 'Hearing4all', University of OldenburgOldenburg, Germany; Cognitive Psychology Lab, Department of Psychology, University of OldenburgOldenburg, Germany
| | - Christiane M Thiel
- Cluster of Excellence 'Hearing4all', University of OldenburgOldenburg, Germany; Biological Psychology Lab, Department of Psychology, University of OldenburgOldenburg, Germany
| | - Kirsten C Wagener
- Cluster of Excellence 'Hearing4all', University of OldenburgOldenburg, Germany; Hörzentrum Oldenburg GmbHOldenburg, Germany
| | - Markus Meis
- Cluster of Excellence 'Hearing4all', University of OldenburgOldenburg, Germany; Hörzentrum Oldenburg GmbHOldenburg, Germany
| | - Hans Colonius
- Cluster of Excellence 'Hearing4all', University of OldenburgOldenburg, Germany; Cognitive Psychology Lab, Department of Psychology, University of OldenburgOldenburg, Germany
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8
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Fournier P, Schönwiesner M, Hébert S. Loudness modulation after transient and permanent hearing loss: implications for tinnitus and hyperacusis. Neuroscience 2014; 283:64-77. [PMID: 25135356 DOI: 10.1016/j.neuroscience.2014.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/06/2014] [Accepted: 08/07/2014] [Indexed: 11/19/2022]
Abstract
Loudness is the primary perceptual correlate of sound intensity. The relationship between sound intensity and loudness is not fixed, and can be modified by short-term sound deprivation or stimulation. Deprivation increases sound sensitivity, whereas stimulation decreases it. We review the effects of short-term auditory deprivation and stimulation on the auditory central nervous system of humans and animals, and we extend the discussion to permanent auditory deprivation (hearing loss) and auditory pathologies of loudness perception. Although there is sufficient evidence to conclude that loudness can be modulated in normal hearing listeners by temporary sound deprivation and stimulation, evidence is scanter for the hearing-impaired listeners. In addition, cortical effects of sound deprivation and stimulation in humans, which may correlate with loudness coding, are still largely unknown and should be the target of future research.
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Affiliation(s)
- P Fournier
- School of Speech Pathology and Audiology, Université de Montréal, Montréal, Québec, Canada; International Laboratory for Research on Brain, Music, and Sound (BRAMS), Université de Montréal, Montréal, Québec, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), Montréal, Québec, Canada
| | - M Schönwiesner
- International Laboratory for Research on Brain, Music, and Sound (BRAMS), Université de Montréal, Montréal, Québec, Canada; Department of Psychology, Université de Montréal, Montréal, Québec, Canada
| | - S Hébert
- School of Speech Pathology and Audiology, Université de Montréal, Montréal, Québec, Canada; International Laboratory for Research on Brain, Music, and Sound (BRAMS), Université de Montréal, Montréal, Québec, Canada; Centre de recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM), Montréal, Québec, Canada.
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9
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Amitay S, Zhang YX, Jones PR, Moore DR. Perceptual learning: top to bottom. Vision Res 2013; 99:69-77. [PMID: 24296314 DOI: 10.1016/j.visres.2013.11.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 11/18/2013] [Accepted: 11/20/2013] [Indexed: 11/30/2022]
Abstract
Perceptual learning has traditionally been portrayed as a bottom-up phenomenon that improves encoding or decoding of the trained stimulus. Cognitive skills such as attention and memory are thought to drive, guide and modulate learning but are, with notable exceptions, not generally considered to undergo changes themselves as a result of training with simple perceptual tasks. Moreover, shifts in threshold are interpreted as shifts in perceptual sensitivity, with no consideration for non-sensory factors (such as response bias) that may contribute to these changes. Accumulating evidence from our own research and others shows that perceptual learning is a conglomeration of effects, with training-induced changes ranging from the lowest (noise reduction in the phase locking of auditory signals) to the highest (working memory capacity) level of processing, and includes contributions from non-sensory factors that affect decision making even on a "simple" auditory task such as frequency discrimination. We discuss our emerging view of learning as a process that increases the signal-to-noise ratio associated with perceptual tasks by tackling noise sources and inefficiencies that cause performance bottlenecks, and present some implications for training populations other than young, smart, attentive and highly-motivated college students.
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Affiliation(s)
- Sygal Amitay
- Medical Research Council Institute of Hearing Research, University Park, Nottingham NG7 2RD, United Kingdom.
| | - Yu-Xuan Zhang
- Medical Research Council Institute of Hearing Research, University Park, Nottingham NG7 2RD, United Kingdom.
| | - Pete R Jones
- Medical Research Council Institute of Hearing Research, University Park, Nottingham NG7 2RD, United Kingdom.
| | - David R Moore
- Medical Research Council Institute of Hearing Research, University Park, Nottingham NG7 2RD, United Kingdom.
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Abstract
There is currently a strong interest among both audiologists and hearing researchers to find a physiological measure that can be used as a marker of how amplified sounds are processed by the brain (i.e., hearing aid fitting) or how the brain changes with exposure to amplified sounds (i.e., hearing aid acclimatization). Currently, auditory evoked potentials are used, or proposed to be used, for both of these purposes to some degree. It is clear from the literature that some of these uses are potentially useful clinically while others are quite problematic. The current state of aided cortical auditory evoked potentials will be discussed relative to their application to hearing aid fitting/verification and in understanding hearing aid acclimatization. Future areas of promise as well as current gaps in the literature will also be addressed.
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Affiliation(s)
- Curtis J Billings
- National Center for Rehabilitative Auditory Research, Portland VA Medical Center, Portland, OR, Department of Otolaryngology/Head & Neck Surgery, Oregon Health & Science University, Portland, OR
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11
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Munro KJ, Merrett JF. Brainstem plasticity and modified loudness following short-term use of hearing aids. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 133:343-349. [PMID: 23297907 DOI: 10.1121/1.4770234] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Previous research has shown that the threshold of the middle ear acoustic reflex is modified in adult listeners following 1 week of continuous monaural sensory deprivation [Munro and Blount, J. Acoust. Soc. Am. 126, 568-571 (2009)]. The results of the present study provide evidence of plasticity in the brainstem of adult listeners following monaural auditory stimulation. Acoustic reflexes were obtained at a higher sound pressure level in the ear that had been fitted with a low-gain hearing aid for 5 days. These changes are in the opposite direction to those reported after sensory deprivation and are consistent with a gain control mechanism mediated by a process within the brainstem. Stimuli were reported as less loud after hearing aid use but the relationship with changes to the acoustic reflex threshold was not statistically significant.
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Affiliation(s)
- Kevin J Munro
- School of Psychological Sciences, University of Manchester, Manchester M13 9PL, United Kingdom.
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12
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Bertoli S, Probst R, Bodmer D. Late auditory evoked potentials in elderly long-term hearing-aid users with unilateral or bilateral fittings. Hear Res 2011; 280:58-69. [PMID: 21569828 DOI: 10.1016/j.heares.2011.04.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 03/29/2011] [Accepted: 04/14/2011] [Indexed: 11/25/2022]
Abstract
This study investigated the effects of long-term unilateral and bilateral amplification on central auditory processing in elderly people with symmetrical hearing loss using late auditory evoked potentials. It was hypothesized that in the unilateral setting stimulation of the aided ear would yield an acclimatization effect with larger amplitudes and shorter latencies of the components P1, N1 and P2 compared to those of the unaided ear. Auditory evoked potentials were elicited by 500, 1000 and 2000 Hz pure tones at 55, 70 and 85 dB SPL presentation level delivered either to the left or right ear. Unilaterally and bilaterally fitted experienced hearing-aid users and a control group of normally hearing adults, all aged at least 60 years, participated. The responses of the unilateral hearing-aid users did not differ significantly for any of the components P1, N1 or P2 between the aided and unaided ears, but a significant interaction between ear and frequency was present for P2 amplitudes. P2 amplitudes were significantly smaller for the 0.5- and 1-kHz stimuli and tended to be larger for the 2-kHz stimulus in the aided ear suggesting an acclimatization effect. Larger P2 amplitudes were observed in the unilaterally fitted group, which was interpreted as a correlate of more effortful auditory processing in unilaterally fitted people.
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Affiliation(s)
- Sibylle Bertoli
- Department of Otorhinolaryngology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland.
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von Ilberg CA, Baumann U, Kiefer J, Tillein J, Adunka OF. Electric-Acoustic Stimulation of the Auditory System: A Review of the First Decade. ACTA ACUST UNITED AC 2011; 16 Suppl 2:1-30. [DOI: 10.1159/000327765] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 02/21/2011] [Indexed: 11/19/2022]
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14
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Hamilton AM, Munro KJ. Uncomfortable loudness levels in experienced unilateral and bilateral hearing aid users: Evidence of adaptive plasticity following asymmetrical sensory input? Int J Audiol 2010; 49:667-71. [DOI: 10.3109/14992021003713114] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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15
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Munro KJ, Blount J. Adaptive plasticity in brainstem of adult listeners following earplug-induced deprivation. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 126:568-71. [PMID: 19640020 DOI: 10.1121/1.3161829] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Previous research has shown that loudness perception is modified in adult listeners following 2 weeks of continuous sensory deprivation or stimulation [Formby, C. et al. (2003). J. Acoust. Soc. Am. 114, 55-58]. However, it is not known if the auditory system undergoes physiological changes or if the listeners simply recalibrate their behavioral criteria such that they become more, or less, conservative following sensory deprivation and stimulation, respectively. The results of this study, comparing threshold of the middle ear acoustic reflex in the two ears of adult listeners after use of a unilateral earplug, are consistent with adaptive plasticity. Acoustic reflexes were measured at a lower sound pressure level in the ear that had been plugged for 7 days. Thus, the effect is consistent with a central gain mechanism mediated by a process within the brainstem.
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Affiliation(s)
- Kevin J Munro
- School of Psychological Sciences, University of Manchester, Manchester, United Kingdom.
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Paiement P, Champoux F, Bacon B, Lassonde M, Gagné JP, Mensour B, Leroux JM, Lepore F. Functional reorganization of the human auditory pathways following hemispherectomy: An fMRI demonstration. Neuropsychologia 2008; 46:2936-42. [DOI: 10.1016/j.neuropsychologia.2008.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 05/28/2008] [Accepted: 06/03/2008] [Indexed: 10/21/2022]
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17
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Munro KJ. Reorganization of the adult auditory system: perceptual and physiological evidence from monaural fitting of hearing aids. Trends Amplif 2008; 12:254-71. [PMID: 18694879 PMCID: PMC4134895 DOI: 10.1177/1084713808323483] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Changes in the sensory environment modify our sensory experience and may result in experience-related or learning-induced reorganization within the central nervous system. Hearing aids change the sensory environment by stimulating a deprived auditory system; therefore, they may be capable of inducing changes within the central auditory system. Examples of studies that have shown hearing aid induced perceptual and/or physiological changes in the adult human auditory system are discussed. Evidence in the perceptual domain is provided by studies that have investigated (a) speech perception, (b) intensity discrimination, and (c) loudness perception. Evidence in the physiological domain is provided by studies that have investigated acoustic reflex thresholds and event-related potentials. Despite the controversy in the literature concerning the rate, extent, and clinical significance of the acclimatization effect, there is irrefutable evidence that the deprived auditory system of some listeners can be modified with hearing aid experience.
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Affiliation(s)
- Kevin J Munro
- School of Psychological Sciences, University of Manchester, United Kingdom.
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18
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Munro KJ. Reorganization of the adult auditory system: perceptual and physiological evidence from monaural fitting of hearing AIDS. Trends Amplif 2008; 12:85-102. [PMID: 18567590 PMCID: PMC4111427 DOI: 10.1177/1084713808316173] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Changes in the sensory environment modify our sensory experience and may result in experience-related or learning-induced reorganization within the central nervous system. Hearing aids change the sensory environment by stimulating a deprived auditory system; therefore, they may be capable of inducing changes within the central auditory system. Examples of studies that have shown hearing aid induced perceptual and/or physiological changes in the adult human auditory system are discussed. Evidence in the perceptual domain is provided by studies that have investigated (a) speech perception, (b) intensity discrimination, and (c) loudness perception. Evidence in the physiological domain is provided by studies that have investigated acoustic reflex thresholds and event-related potentials. Despite the controversy in the literature concerning the rate, extent, and clinical significance of the acclimatization effect, there is irrefutable evidence that the deprived auditory system of some listeners can be modified with hearing aid experience.
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Affiliation(s)
- Kevin J Munro
- School of Psychological Sciences, University of Manchester, United Kingdom.
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Asymmetry in the auditory brainstem response following experience of monaural amplification. Neuroreport 2008; 18:1871-4. [PMID: 18090329 DOI: 10.1097/wnr.0b013e3282f1b003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hearing aids can induce perceptual changes in some elderly listeners and there is recent evidence that this might be associated with reorganization within the auditory system. We compared the click-evoked auditory brainstem response in adults with and without monaural hearing aid experience. In listeners with monaural hearing aid experience, the mean peak-to-peak amplitude between wave V and SN10 was approximately 100 nV larger in the ear with hearing aid experience and this difference was statistically significant (P<0.01). The response was symmetrical in adults with no hearing aid experience. This suggests that hearing aids can induce physiological changes at the level of the auditory brainstem in elderly monaural hearing aid users.
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