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.

Evaluating cochlear function and the effects of noise exposure in the B6.CAST+Ahl mouse with distortion product otoacoustic emissions

2004 ◽  
Vol 194 (1-2) ◽  
pp. 87-96 ◽  
Author(s):  
Ana E Vázquez ◽  
Ana M Jimenez ◽  
Glen K Martin ◽  
Anne E Luebke ◽  
Brenda L Lonsbury-Martin
Keyword(s):  
Otoacoustic Emissions ◽  
Noise Exposure ◽  
Distortion Product Otoacoustic Emissions ◽  
Cochlear Function ◽  
Distortion Product

Early Changes in Auditory Function As a Result of Platinum Chemotherapy: Use of Extended High-Frequency Audiometry and Evoked Distortion Product Otoacoustic Emissions

2007 ◽  
Vol 25 (10) ◽  
pp. 1190-1195 ◽  
Author(s):  
Kristin R. Knight ◽  
Dale F. Kraemer ◽  
Christiane Winter ◽  
Edward A. Neuwelt
Keyword(s):  
High Frequency ◽  
Otoacoustic Emissions ◽  
Distortion Product Otoacoustic Emissions ◽  
Auditory Function ◽  
Cochlear Function ◽  
Serial Measurement ◽  
Distortion Product ◽  
High Frequency Audiometry ◽  
Platinum Based Chemotherapy ◽  
Platinum Chemotherapy

Purpose The objective is to describe progressive changes in hearing and cochlear function in children and adolescents treated with platinum-based chemotherapy and to begin preliminary evaluation of the feasibility of extended high-frequency audiometry and distortion product otoacoustic emissions for ototoxicity monitoring in children. Patients and Methods Baseline and serial measurement of conventional pure-tone audiometry (0.5 to 8 kHz) and evoked distortion product otoacoustic emissions (DPOAEs) were conducted for 32 patients age 8 months to 20 years who were treated with cisplatin and/or carboplatin chemotherapy. Seventeen children also had baseline and serial measurement of extended high-frequency (EHF) audiometry (9 to 16 kHz). Audiologic data were analyzed to determine the incidence of ototoxicity using the American Speech-Language-Hearing Association criteria, and the relationships between the different measures of ototoxicity. Results Of the 32 children, 20 (62.5%) acquired bilateral ototoxicity in the conventional frequency range during chemotherapy treatment, and 26 (81.3%) had bilateral decreases in DPOAE amplitudes and dynamic range. Of the 17 children with EHF audiometry results, 16 (94.1%) had bilateral ototoxicity in the EHF range. Pilot data suggest that EHF thresholds and DPOAEs show ototoxic changes before hearing loss is detected by conventional audiometry. Conclusion EHF audiometry and DPOAEs have the potential to reveal earlier changes in auditory function than conventional frequency audiometry during platinum chemotherapy in children.

scholarly journals Cochlear function in patients with chronic kidney disease

2013 ◽  
Vol 60 (1) ◽  
Author(s):  
Samantha Marlanie Govender ◽  
Cyril Devdas Govender ◽  
Glenda Matthews
Keyword(s):  
Chronic Kidney Disease ◽  
Hearing Loss ◽  
Kidney Disease ◽  
Otoacoustic Emissions ◽  
Pure Tone ◽  
Pure Tone Audiometry ◽  
Drug Intake ◽  
Cochlear Function ◽  
Distortion Product ◽  
Cochlear Dysfunction

Objective: To evaluate cochlear functioning in patients (18 - 45 years old) with varying stages of chronic kidney disease (CKD). Using purposive sampling, 50 participants, 10 in each of the 5 stages of CKD, were selected and underwent pure tone audiometric testing and distortion product otoacoustic emissions (DPOAEs).Results: Significant differences (p<0.05) were found between pure tone audiometry and DPOAEs in detecting early cochlear dysfunction in the high-frequency range in stages 3 (6 000/5 000 Hz; p=0.00), 4 (6 000/5 000 Hz; p<0.03) and 5 (4 000/3 333 Hz; p<0.01, 8 000/6 667 Hz:p<0.05) with DPOAEs being more sensitive in identifying early cochlear dysfunction. Patients in stages 1 and 2 presented with normal puretone thresholds and DPOAEs, suggesting that cochlear functioning in these patients was normal. Early cochlear dysfunction, thereby indicating a subclinical hearing loss, was identified in stages 3, 4 and 5 by DPOAE testing. In addition, blood test results, drug intake and concomitant conditions were recorded and analysed which suggested a relationship between reduced cochlear functioning and increased electrolyte levels, treatment regimens and concomitant conditions.Conclusion: Participants in the later stages of CKD presented with early cochlear dysfunction, presenting with subclinical hearing loss. It was postulated that this subclinical hearing loss resulted from a combination of electrolytic, urea and creatinine imbalances, together with concomitant medical conditions and ototoxic drug intake. It was concluded that audiological monitoring be included in the management of patients with CKD and that DPOAEs be introduced as part of the test battery to monitor cochlear function in patients with varying degrees of CKD.

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.

Forte Fortissimo for Amateur Musicians: No Effect on Otoacoustic Emissions

2013 ◽  
Vol 28 (1) ◽  
pp. 3-8 ◽  
Author(s):  
Ole J Møllerløkken ◽  
Nils Magerøy ◽  
Magne Bråtveit ◽  
Ola Lind ◽  
Bente E Moen
Keyword(s):  
Otoacoustic Emissions ◽  
Office Workers ◽  
Cochlear Function ◽  
Distortion Product ◽  
Brass Band ◽  
Hearing Ability ◽  
Sound Levels ◽  
Amateur Musicians ◽  
Before And After ◽  
Noise Measurements

Many amateur musicians are likely to be exposed to high sound levels during rehearsals. Measuring otoacoustic emissions (OAE) is an objective technique to assess hearing ability and can be used as an early predictor of hearing loss. This study aimed to record sound levels at an amateur brass band rehearsal and to examine the cochlear function of the musicians by evaluating distortion product (DP) OAE amplitudes before and after sound exposure. Twenty-four brass band musicians and 10 office workers were examined with personal noise measurements and DPOAE tests before and after a music rehearsal or one office workday, respectively. The sound levels in the brass band ranged from 92 to 100 dB(A), LaEQ 96 dB(A). However, the amateur brass band members had no change in DPOAEs after this exposure compared to pre-exposure levels and compared to office workers.

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.

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 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.

scholarly journals Does Vincristine affect Cochlear function in children with acute lymphoblastic leukaemia?

2016 ◽  
Vol 27 (1) ◽  
pp. 3-7
Author(s):  
Suchetha Rao ◽  
Ranjith Kumar ◽  
Jayashree Bhat ◽  
Nutan Kamath
Keyword(s):  
High Frequency ◽  
Otoacoustic Emissions ◽  
Lymphoblastic Leukemia ◽  
Statistical Significance ◽  
Pure Tone Audiometry ◽  
Cochlear Function ◽  
Hearing Sensitivity ◽  
Distortion Product ◽  
High Frequency Audiometry

Context: Vincristine chemotherapy has dose dependent ototoxicity. Early detection of ototoxicity is better with otoacoustic emissions and high frequency audiometry than conventional pure tone audiometry. The study was done to see if vincristine treatment interferes with hearing sensitivity in children.Methods and Material: A prospective study was conducted on twenty-three children with acute lymphoblastic leukemia (ALL) on Multi Center Protocol (MCP 841).These were subjected to conventional audiometry, high frequency audiometry and distortion product otoacoustic emissions (DPOAEs) before starting chemotherapy. The follow up audiological evaluation after early intensive phase chemotherapy (approximately 6 months) was conducted in thirteen children, who received 12 doses of vincristine (1.4 mg/m2), cranial irradiation of 1800cGy (>3 years) as per protocol and antibiotics as per clinical demands.Results: Baseline audiological evaluation was normal. Follow-up evaluation DPOAEs showed a declining tendency, however changes did not reach statistical significance. Differences in median hearing thresholds prior and post treatment in higher frequency audiometry were also minimal which was not statistically significant. Conventional audiometric thresholds were not altered.Conclusions: The reduction in the signal noise ratio of DPOAE, and reduced hearing sensitivity in high frequencies in post chemotherapy in comparison with baseline measures cannot be ignored though it has failed to reach the level of statistical significance. children on vincristine should have a pre chemotherapy and follow up audiological evaluation with DPOAE The results of the present study needs to be strengthened by including larger sample and long term follow up.Bangladesh J Medicine Jan 2016; 27(1) : 3-7

Cochlear outer hair cell electromotility can provide force for both low and high intensity distortion product otoacoustic emissions

1998 ◽  
Vol 126 (1-2) ◽  
pp. 67-74 ◽  
Author(s):  
Gregory I Frolenkov ◽  
Inna A Belyantseva ◽  
Mauricio Kurc ◽  
Mary Ann Mastroianni ◽  
Bechara Kachar
Keyword(s):  
Hair Cell ◽  
High Intensity ◽  
Otoacoustic Emissions ◽  
Outer Hair Cell ◽  
Distortion Product Otoacoustic Emissions ◽  
Distortion Product
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