Protection against Noise Trauma by Sound Conditioning

1997 ◽  
Vol 76 (4) ◽  
pp. 248-255 ◽  
Author(s):  
Barbara Canlon
Keyword(s):  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Human Subjects ◽  
Acoustic Stimulus ◽  
Conditioning Stimulus ◽  
Outer Hair Cells ◽  
Noise Trauma ◽  
Distortion Product ◽  
Underlying Mechanisms ◽  
X 24

Sound conditioning provides protection against a subsequent noise trauma. The sound conditioning paradigm consists of a low-level, long-term, non-damaging acoustic stimulus (1 kHz, 81 dB SPL x 24 days). Morphological and physiological alterations are not induced by the sound conditioning stimulus alone. In addition, the middle ear muscles have been shown not to be influenced by sound conditioning. It has been shown that after exposure to a traumatic stimulus, sound conditioning protects the outer hair cell morphology (fewer missing outer hair cells), as well as physiology (distortion product otoacoustic emissions) compared to an unconditioned group exposed only to the traumatic stimulus. Further studies are needed in order to establish the underlying mechanisms for the phenomenon of sound conditioning. Nevertheless, since sound-conditioning experiments have been successfully applied to human subjects our understanding of hearing impaired individuals has been enhanced.

Early Evidence of Cochlear Damage in a Large Sample of Percussionists

2005 ◽  
Vol 20 (3) ◽  
pp. 135-139
Author(s):  
Jodee A Pride ◽  
David R Cunningham
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Damage ◽  
Normal Hearing ◽  
Outer Hair Cells ◽  
Sensory Loss ◽  
Distortion Product ◽  
Hair Cell Damage

Percussionists can be exposed to intermittent sound stimuli that exceed 145 dB SPL, although damage may occur to the outer hair cells at levels of 120 dB SPL. The present study measured distortion-product otoacoustic emissions (DPOAEs) in a group of 86 normal-hearing percussionists and 39 normal-hearing nonpercussionists. Results indicate that normal-hearing percussionists have lower DPOAE amplitudes than normal-hearing nonpercussionists. DPOAE amplitudes were significantly lower at 6000 Hz in both the left and right ears for percussionists. Percussionists also more frequently had absent DPOAEs, with the greatest differences occurring at 6000 Hz (absent DPOAEs in 25% of percussionists vs 10% of nonpercussionists). When all frequencies are considered as a group, 33% of the percussionists had an absent DPOAE in either ear at some frequency, compared to only 23% of the nonpercussionists. Otoacoustic emissions are more sensitive to outer hair cell damage than pure-tone threshold measurements and can serve as an important measurement of sensory loss (i.e., outer hair cell damage) in musicians before the person perceives the hearing loss. DPOAE monitoring for musicians, along with appropriate education and intervention, might help prevent or minimize music-induced hearing loss.

scholarly journals Evaluation of outer hair cells function of non-operated ear after mastoid drilling using distortion-product otoacoustic emissions

2019 ◽  
Vol 5 (3) ◽  
pp. 130-133
Author(s):  
Virender Singh ◽  
◽  
BS Rakesh ◽  
MB Bharathi ◽  
Kota Harish Nag ◽  
...  
Keyword(s):  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Outer Hair Cells ◽  
Distortion Product Otoacoustic Emissions ◽  
Mechanical Trauma ◽  
Suppurative Otitis Media ◽  
Distortion Product ◽  
Study Materials ◽  
And Gender

Aim: To analyze the effect of acoustic and mechanical trauma of drilling on the outer hair cell function of the non operated ear using distortion-product otoacoustic emissions (DPOAE’s) after mastoidectomy and its relation with the duration of drilling, age, and gender of the patient along with duration and permanency of the effects. Study Design: Observational study. Materials and Methods: Screening DPOAE’s were recorded preoperatively, immediate postoperative period, one hour postoperatively, 1st and 7th postoperative days in the normal ear in 94 patients who underwent tympanomastoidectomy for unilateral chronic suppurative otitis media (CSOM). DPOAE’s were measured using Neuro-audio-screener (Neurosoft Inc.) at 1.5 KHz, 2.1 KHz, 3.3 KHz, and 4.2 KHz. If DPOAE’s were absent preoperatively, the patients were not evaluated further and patients who had absent DPOAE’s post-operatively were successively followed till DPOAE’s were regained. Results: Of the 94 patients included, in 62 patients DPOAE’s were present preoperatively. Out of these 62, in 30 patients DPOAE’s were absent immediate postoperatively. On repeat testing, DPOAE’s were absent in 20 patients after 1 hour and in 8 patients after 1 day. On re-evaluation of these 8 patients after 1 week all of them had regained the DPOAE’s. In terms of duration of drilling, 66.6% patients in immediate post operative period, 90% patients in 1-hour post operative and 100 % patients on post operative day 1, having absent DPOAE’s had drilling time more than 60 minutes. Patients more than 30 years of age are affected more, but there is no preponderance for any gender. Conclusion: Nonoperated ear does have the effect of acoustic and mechanical trauma by vibration transmitted from another side during drilling of the operative ear mastoid bone. This effect is temporary and depends on the duration of drilling also.

Changes in Otoacoustic Emissions and Auditory Brain Stem Response after C/s-Platinum Exposure in Gerbils

1997 ◽  
Vol 116 (6) ◽  
pp. 585-592 ◽  
Author(s):  
Kathleen C. Y. Sie ◽  
Susan J. Norton
Keyword(s):  
Hearing Loss ◽  
Brain Stem ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Outer Hair Cells ◽  
Distortion Product Otoacoustic Emissions ◽  
Auditory Brain Stem Response ◽  
Distortion Product ◽  
Auditory Brain Stem ◽  
Significant Difference

Ototoxicity associated with cis-platinum administration commonly presents as hearing loss and tinnitus. The hearing loss is usually an irreversible, high-frequency sensorineural loss. Histologic studies in humans and animals suggest that the outer hair cells (OHCs) are most susceptible to cis-platinum. Evoked otoacoustic emissions (EOAE), as a measure of outer hair cell function, are potentially useful in following ototoxic insults involving OHCs. Distortion-product otoacoustic emissions (DPOAE) test frequency-specific regions of the cochlea and therefore may be particularly well suited for monitoring ototoxic injuries. We measured distortion product otoacoustic emissions, at f2 = 2, 4, 6, 8, 10, and 12 kHz, in gerbils after a single large dose of cis-platinum. Animals treated with saline served as controls. The findings were compared to auditory brain stem evoked response (ABR) thresholds, using tone pips of the same frequencies. The DPOAE and ABR thresholds were measured before treatment and again 2, 5, and 14 days after drug administration. The changes in DPOAE were compared with the changes in ABR. No treatment effect was noted in the 2-day group. Animals treated with c/s-platinum demonstrated significant elevation of DPOAE and ABR thresholds compared with control animals at 5 and 14 days. There was no significant difference between the threshold changes in the 5-and 14-day groups.

scholarly journals THE STUDY OF MATURATION OF THE AUDITORY ANALYZER RABBIT ACCORDING DISTORTION-PRODUCT OTOACOUSTIC EMISSIONS

2013 ◽  
Vol 68 (11) ◽  
pp. 94-97
Author(s):  
I. N. D'yakonova ◽  
Yu. S. Ishanova ◽  
I. V. Rakhmanova
Keyword(s):  
Hair Cells ◽  
Otoacoustic Emissions ◽  
Normative Data ◽  
Outer Hair Cell ◽  
Rabbit Model ◽  
Outer Hair Cells ◽  
Distortion Product Otoacoustic Emissions ◽  
Acoustic Response ◽  
Auditory Analyzer ◽  
Distortion Product

Aim: In our chronic experiment to  register changes of acoustic response of Distortion-Product Otoacoustic Emissions (DPOAE) of intact rabbits in postnatal ontogenesis for the purpose of getting normative data which can be used for studying impact of pathological factors on auditory function and maturation of activity of outer hair cell in ontogenesis. Materials and methods: Study of otoacoustic emissions used mature chinchilla rabbits with a 19 day life of up to 3 months. Results: in the course of ripening were obtained functional activity of outer hair cells of the cochlea. Conclusion: normative data obtained allow us to study using a rabbit model, the pathological effects of agents on the maturation of the outer hair cells of the cochlea in the experiment.

Conditioning-Related Protection From Acoustic Injury: Effects of Chronic Deefferentation and Sham Surgery

1997 ◽  
Vol 78 (6) ◽  
pp. 3095-3106 ◽  
Author(s):  
Sharon G. Kujawa ◽  
M. Charles Liberman
Keyword(s):  
Brain Stem ◽  
Otoacoustic Emissions ◽  
Noise Exposure ◽  
Outer Hair Cell ◽  
Acoustic Stimulus ◽  
Cell Region ◽  
Distortion Product ◽  
Traumatic Exposure ◽  
Sham Surgery ◽  
Conditioning Treatment

Kujawa, Sharon G. and M. Charles Liberman. Conditioning-related protection from acoustic injury: effects of chronic deefferentation and sham surgery. J. Neurophysiol. 78: 3095–3106, 1997. The inner ear can be made less vulnerable to acoustic injury by a “conditioning” treatment involving exposure to a moderate-level acoustic stimulus before the acoustic overexposure. The present study was designed to explore the role of the olivocochlear (OC) system in this “protection.” Guinea pigs were divided into a number of groups: some (trauma-only) were exposed to a traumatic noise for 4 h at 109 dB SPL; others (condition/trauma) were conditioned by daily exposure to the same noise at 85 dB SPL before the traumatic exposure. In OC-intact animals, the condition/trauma group showed significantly less permanent threshold shift (PTS) than the trauma-only group as measured via compound action potentials and distortion-product otoacoustic emissions (DPOAEs). Other animals with identical noise-exposure regimens underwent deefferentation surgery before the start of conditioning: the OC bundle (OCB) was cut in the brain stem, either at the midline (cutting the crossed OCB to both ears) or at the sulcus limitans (cutting all OC fibers to 1 side). Lesion success was quantified by measuring OC fascicles to the outer hair cell region in each ear. The results from the surgical groups showed that total loss of the OCB significantly increased the noise-induced PTS, whereas loss of the COCB only did not; that the conditioning exposure in deefferented animals increased, rather than decreased, the PTS from the traumatic exposure; and that animals undergoing sham surgery (brain stem cuts that failed to transect the OCB) appeared protected whether or not they received the conditioning noise exposure. The latter result suggests that conditioning-related protection may arise from a generalized stress response, which can be elicited by noise exposure, brain surgery, or a variety of other means. The former results make an OC role in the conditioning process, per se, difficult to assess, given the large effects of OC activity on general acoustic vulnerability.

DPOAE-Grams in Patients with Acute Tonal Tinnitus

2005 ◽  
Vol 132 (4) ◽  
pp. 550-553 ◽  
Author(s):  
Haralampos Gouveris ◽  
Jan Maurer ◽  
Wolf Mann
Keyword(s):  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Cell Function ◽  
Hearing Threshold ◽  
Normal Hearing ◽  
Outer Hair Cells ◽  
Controlled Study ◽  
High Frequency Region ◽  
Mean Values ◽  
Distortion Products

OBJECTIVE: To investigate cochlear outer hair cell function in patients with acute tonal tinnitus and normal or near-normal hearing threshold. STUDY DESIGN AND SETTING: Prospective controlled study in an academic tertiary health center. Distortion products of otoacoustic emissions (DPOAE)-grams of 32 ears with acute tonal tinnitus and normal hearing or minimal hearing loss were compared with those of 17 healthy nontinnitus ears. RESULTS: Tinnitus ears exhibited relatively increased amplitudes of DPOAE at high frequencies (4-6.3 kHz) when compared with the group of healthy ears and relatively decreased DPOAE amplitudes at middle frequencies (1650-2400 Hz). Statistically significant ( P < 0.01) increased mean values of DPOAE amplitudes were observed only at a frequency of f2 equal to 4.9 kHz. CONCLUSIONS AND SIGNIFICANCE: These findings suggest an altered functional state of the outer hair cells at a selected high-frequency region of the cochlea in ears with acute tonal tinnitus and normal or near-normal hearing threshold.

scholarly journals Time-domain analysis of distortion-product otoacoustic emissions using a hydrodynamic cochlea model

2017 ◽  
Vol 3 (2) ◽  
pp. 453-456
Author(s):  
Dennis Zelle ◽  
Ernst Dalhoff ◽  
Anthony W. Gummer
Keyword(s):  
Time Domain ◽  
Otoacoustic Emissions ◽  
Short Pulse ◽  
Human Subjects ◽  
Time Domain Analysis ◽  
Distortion Product Otoacoustic Emissions ◽  
Sound Waves ◽  
Cochlear Function ◽  
Distortion Product ◽  
The Time Domain

AbstractAs a by-product of nonlinear amplification in the cochlea, the inner ear emits sound waves in response to two tones with different frequencies. These sound waves are measurable in the ear canal as distortion-product otoacoustic emissions (DPOAEs). DPOAEs putatively consist of two components emerging at different locations in the cochlea. Wave interference between the two components limits the accuracy of DPOAEs as a noninvasive measure of cochlear function. Using short stimulus pulses instead of continuous stimuli, the two DPOAE components can be separated in the time domain due to their different latencies. The present work utilizes a nonlinear hydrodynamic cochlea model to simulate short-pulse DPOAEs in the time domain. When adding irregularities to the mechanical parameters of the model, the simulated DPOAE signals show two distinguishable components and long-lasting beat tones, similar to band-pass filtered experimental data from normal-hearing human subjects. The model results suggest that the beat tones can occur solely due to interference of the coherent-reflection component with the fading nonlinear-distortion component.

scholarly journals Is the Level of Noise in a School Environment be Harmful to the Hearing of Teachers?

2020 ◽  
Vol 24 (04) ◽  
pp. e503-e507
Author(s):  
Gabriela Guenther Ribeiro Novanta ◽  
Sergio Luiz Garavelli ◽  
Andre Luiz Lopes Sampaio
Keyword(s):  
Classroom Environment ◽  
School Environment ◽  
Otoacoustic Emissions ◽  
Signal To Noise Ratio ◽  
Signal Amplitude ◽  
Daily Basis ◽  
Outer Hair Cells ◽  
Distortion Product ◽  
Teachers And Students ◽  
The Difference

Abstract Introduction The excessive noise observed in the school environment can cause damages or losses to the learning process as well as risks to the health of teachers and students, such as physical, mental and social impairments, including, among them, hearing loss. Objective To assess otoacoustic emissions in teachers and determine whether classroom noise reduces distortion-product otoacoustic emissions (DPOAEs) amplitude and signal-to-noise ratio (SNR). Method Sixty-seven teachers were evaluated using otoacoustic emissions testing in two situations: after hearing rest and after the working day. Results Signal amplitude (p = 0.044 [2 kHz]; p = 0.01 [4 kHz]) and SNR for frequencies of 2 kHz (p = 0.008) and 4 kHz (p = 0.001) decreased significantly between time points. Mean classroom noise was associated with the magnitude of the difference in signal amplitude at 2 kHz (p = 0.017) and 4 kHz (p = 0.015), and SNR at 4 kHz (p = 0.023). Conclusions There was a decrease in the amplitude and in the SNR after exposure to the noise in the classroom environment. The high levels of sound pressure that teachers are exposed to on a daily basis can cause a temporary change in the outer hair cells of the Corti organ, and these changes may become permanent over time.

scholarly journals Overexpression of SK2 Channels Enhances Efferent Suppression of Cochlear Responses Without Enhancing Noise Resistance

2007 ◽  
Vol 97 (4) ◽  
pp. 2930-2936 ◽  
Author(s):  
Stéphane F. Maison ◽  
Lisan L. Parker ◽  
Lucy Young ◽  
John P. Adelman ◽  
Jian Zuo ◽  
...  
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Hair Cells ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Outer Hair Cells ◽  
Sk Channels ◽  
Cochlear Function ◽  
Cochlear Hair Cells ◽  
Efferent Suppression

Cochlear hair cells express SK2, a small-conductance Ca2+-activated K+ channel thought to act in concert with Ca2+-permeable nicotinic acetylcholine receptors (nAChRs) α9 and α10 in mediating suppressive effects of the olivocochlear efferent innervation. To probe the in vivo role of SK2 channels in hearing, we examined gene expression, cochlear function, efferent suppression, and noise vulnerability in mice overexpressing SK2 channels. Cochlear thresholds, as measured by auditory brain stem responses and otoacoustic emissions, were normal in overexpressers as was overall cochlear morphology and the size, number, and distribution of efferent terminals on outer hair cells. Cochlear expression levels of SK2 channels were elevated eightfold without striking changes in other SK channels or in the α9/α10 nAChRs. Shock-evoked efferent suppression of cochlear responses was significantly enhanced in overexpresser mice as seen previously in α9 overexpresser mice; however, in contrast to α9 overexpressers, SK2 overexpressers were not protected from acoustic injury. Results suggest that efferent-mediated cochlear protection is mediated by other downstream effects of ACh-mediated Ca2+ entry different from those involving SK2-mediated hyperpolarization and the associated reduction in outer hair cell electromotility.

Kanamycin Depletes Cochlear Polyamines in the Developing Rat

1994 ◽  
Vol 110 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Charles M. Henley
Keyword(s):  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Organ Of Corti ◽  
Aminoglycoside Antibiotics ◽  
Basal Region ◽  
Cochlear Function ◽  
Polyamine Synthesis ◽  
Distortion Product ◽  
Functional Maturation ◽  
Developing Rat

Developing mammals are more sensitive to aminoglycoside antibiotics and other ototoxic agents than adults, with maximum sensitivity occurring during the period of anatomic and functional maturation of the cochlea. For the aminoglycoside antibiotics, the hypersensitive period in rats occurs during the second and third postnatal weeks. Toxicity is initially expressed as outer hair cell (OHC) damage in the high-frequency, basal region of the cochlea. Distortion-product otoacoustic emissions (DPOAEs), physiologic measures of OHC function, are particularly sensitive to aminoglycoside exposure during the period of rapid cochlear physiologic development. Toxicity is characterized by increased DPOAE thresholds and decreased amplitudes. The mechanism of developmental sensitivity to aminoglycosides is unknown. A potential biochemical target of aminoglycosides is the ornithine decarboxylase (ODC)-polyamine pathway. ODC activity is elevated in the developing rat cochlea, aminoglycosides inhibit cochlear ODC in developing rats, and α-difluoromethylornithine (a specific ODC inhibitor) impairs development of cochlear function. In the present study we demonstrate an incomplete polyamnine response to aminoglycoside damage, characterized by inhibition of the polyamines spermidine and spermine and accumulation of putrescine in the organ of Corti. Aminoglycoside inhibition of polyamine synthesis may mediate developmental ototoxic hypersensitivity by interfering with developmental and repair processes.

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