Cochlear Endoscopy with Preservation of Hearing in Guinea Pigs

1994 ◽  
Vol 111 (4) ◽  
pp. 439-445 ◽  
Author(s):  
Thomas Balkany ◽  
Annelle V. Hodges ◽  
Martin Whitehead ◽  
Faramarz Memari ◽  
Glen K. Martin
Keyword(s):  
Guinea Pig ◽  
Brain Stem ◽  
Guinea Pigs ◽  
Otoacoustic Emissions ◽  
Round Window ◽  
Distortion Product Otoacoustic Emission ◽  
Auditory Brain Stem Response ◽  
Distortion Product ◽  
Guinea Pig Cochlea ◽  
Auditory Brain Stem

Advances in fiberoptic technology have revolutionized the way many disorders are treated by otolaryngologists. We have previously described our experiences with cochlear endoscopy during cochlear Implantation. However, endoscopy of the functioning cochlea has not previously been reported. To test the hypothesis that endoscopy of the guinea pig cochlea is possible without catastrophic loss of auditory function, we subjected 20 ears of 10 Hartley-strain albino guinea pigs to limited endoscopy of the cochlea through the round window with evaluation of distortion product otoacoustic emissions and auditory brain stem responses. Insertion of the endoscope caused measurable changes in auditory brain stem response latency and amplitude. Distortion product otoacoustic emission amplitudes were reduced an average of 6 dB with greater loss close to the round window. Frequencies above 18 kHz, corresponding to the region of endoscopy, were not evaluated in this preliminary study and are suspected to have sustained more damage. Results demonstrate that endoscopy of the guinea pig cochlea is possible without major loss of the above physiologic measures in the regions tested. If endoscopy of the cochlea is to become a tool with clinical and basic science applications, refinements in techniques to avoid damage are necessary.

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.

Electrophysiologic Changes in Preterm Neonates: Auditory Brain Stem Response and Distortion Product Otoacoustic Emissions

1997 ◽  
Vol 106 (9) ◽  
pp. 721-728 ◽  
Author(s):  
Rafael E. Quiñónez ◽  
Margie R. Crawford
Keyword(s):  
Brain Stem ◽  
Auditory System ◽  
Otoacoustic Emissions ◽  
Full Term ◽  
Distortion Product Otoacoustic Emissions ◽  
Preterm Neonates ◽  
Auditory Brain Stem Response ◽  
Distortion Product ◽  
Auditory Brain Stem ◽  
Peripheral Auditory System

The purposes of this investigation were to determine 1) if auditory peripheral maturity is present in the newborn; 2) if not, at what age maturational changes occur in the peripheral auditory system from preterm to full-term; and 3) how results of tests used to identify auditory dysfunction in neonates, such as distortion product otoacoustic emissions (DPEs) and auditory brain stem responses (ABRs), change during this period. Longitudinal DPE amplitude and ABR wave I latency measurements were obtained from a single ear of 18 preterm neonates. The DPEs were evoked at f2s of 2, 3, 4, and 5 kHz. The longitudinal data revealed that in general, DPE amplitude increased and ABR wave I latency decreased as a function of postconceptional age. These findings suggest that 1) the peripheral auditory system has not reached maturity in the preterm neonate; 2) maturational changes continue from preterm to full-term; and 3) these changes are reflected in ABR and DPE measurements.

Audiological Study in Guinea Pigs with Type I Allergy Induced in the Inner Ear

1993 ◽  
Vol 102 (7) ◽  
pp. 537-542 ◽  
Author(s):  
Kengo Uno ◽  
Hironori Fukuda ◽  
Kenichiro Miyamura ◽  
Keisuke Masuyama ◽  
Yorinori Kanzaki ◽  
...  
Keyword(s):  
Brain Stem ◽  
Inner Ear ◽  
Guinea Pigs ◽  
Type I ◽  
Auditory Brain Stem Response ◽  
Type I Allergy ◽  
Summating Potential ◽  
Auditory Brain Stem ◽  
Brain Stem Response ◽  
Specific Challenge

Time course studies of electrocochleography and the auditory brain stem response were performed in guinea pigs that were passively sensitized by sera containing antidinitrophenyl reaginic antibody and specifically challenged by dinitrophenyl—bovine serum albumin injected through the stylomastoid foramen. A negative summating potential on electrocochleography was observed from 12 to 48 hours, but not at 72 hours, after the specific challenge. A threshold increase on the auditory brain stem response was observed 15 minutes after the specific challenge; the threshold recovered to the prechallenge level within 7 days. Further, we used Tranilast, a blocking agent of chemical mediator release from mast cells, before the specific challenge. A negative summating potential and head deviation were not observed after the use of this agent. These results suggest that the auditory change provoked in the inner ear of the sensitized guinea pig may have been induced by type I allergy.

scholarly journals Selective Removal of Lateral Olivocochlear Efferents Increases Vulnerability to Acute Acoustic Injury

2007 ◽  
Vol 97 (2) ◽  
pp. 1775-1785 ◽  
Author(s):  
Keith N. Darrow ◽  
Stéphane F. Maison ◽  
M. Charles Liberman
Keyword(s):  
Brain Stem ◽  
Otoacoustic Emissions ◽  
Outer Hair Cells ◽  
Cochlear Nerve ◽  
Sensory Cells ◽  
Neural Responses ◽  
Distortion Product ◽  
Auditory Brain Stem ◽  
Pharmacological Studies

Cochlear sensory cells and neurons receive efferent feedback from the olivocochlear (OC) system. The myelinated medial component of the OC system and its effects on outer hair cells (OHCs) have been implicated in protection from acoustic injury. The unmyelinated lateral (L)OC fibers target ipsilateral cochlear nerve dendrites and pharmacological studies suggest the LOC's dopaminergic component may protect these dendrites from excitotoxic effects of acoustic overexposure. Here, we explore LOC function in vivo by selective stereotaxic destruction of LOC cell bodies in mouse. Lesion success in removing the LOC, and sparing the medial (M)OC, was assessed by histological analysis of brain stem sections and cochlear whole mounts. Auditory brain stem responses (ABRs), a neural-based metric, and distortion product otoacoustic emissions (DPOAEs), an OHC-based metric, were measured in control and surgical mice. In cases where the LOC was at least partially destroyed, there were increases in suprathreshold neural responses that were frequency- and level-independent and not attributable to OHC-based effects. These interaural response asymmetries were not found in controls or in cases where the lesion missed the LOC. In LOC-lesion cases, after exposure to a traumatic stimulus, temporary threshold shifts were greater in the ipsilateral ear, but only when measured in the neural response; OHC-based measurements were always bilaterally symmetric, suggesting OHC vulnerability was unaffected. Interaural asymmetries in threshold shift were not found in either unlesioned controls or in cases that missed the LOC. These findings suggest that the LOC modulates cochlear nerve excitability and protects the cochlea from neural damage in acute acoustic injury.

Neonatal Hearing Screening with Otoscopy, Auditory Brain Stem Response, and Otoacoustic Emissions

1995 ◽  
Vol 113 (2) ◽  
pp. P151-P151
Author(s):  
Karen Jo Doyle ◽  
Barbara Burggraaff ◽  
Sharon Fujikawa ◽  
Ju Kim ◽  
Carol MacArthur
Keyword(s):  
Brain Stem ◽  
Otoacoustic Emissions ◽  
Hearing Screening ◽  
Auditory Brain Stem Response ◽  
Neonatal Hearing Screening ◽  
Auditory Brain Stem ◽  
Brain Stem Response
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