scholarly journals The Estimation of the Time Constant of the Human Inner Ear Pressure Change by Noninvasive Technique

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Raghida Traboulsi ◽  
Georges Poumarat ◽  
Jean Chazal ◽  
Paul Avan ◽  
Thierry Mom ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Intracranial Pressure ◽  
Inner Ear ◽  
Time Constant ◽  
Otoacoustic Emissions ◽  
Pressure Change ◽  
Noninvasive Technique ◽  
Cochlear Aqueduct ◽  
Distortion Product ◽  
Long Time

We propose a noninvasive method to estimate the time constant. The calculation of this factor permits us to understand the pressure variations of the inner ear and also predict the behavior of the flow resistance of the cochlear aqueduct. A set of mathematical relationships incorporating the intralabyrinthine pressure, the intracranial pressure, and the time constant was applied. The modeling process describes the hydrodynamic effects of the cerebrospinal fluid in the intralabyrinthine fluid space, where the input and output of the created model are, respectively, the sinusoidal variation of the respiration signal and the distortion product of otoacoustic emissions. The obtained results were compared with those obtained by different invasive techniques. A long time constant was detected each time when the intracranial pressure increased; this phenomenon is related to the role of the cochlear aqueduct described elsewhere. The interpretation of this model has revealed the ability of these predictions to provide a greater precision for hydrodynamic variation of the inner ear, consequently the variation of the dynamic process of the cerebrospinal fluid.

Cerebrospinal fluid shunting and hearing loss in patients treated for medulloblastoma

2012 ◽  
Vol 9 (4) ◽  
pp. 421-427 ◽  
Author(s):  
Daniel J. Guillaume ◽  
Kristin Knight ◽  
Carol Marquez ◽  
Dale F. Kraemer ◽  
Dianna M. E. Bardo ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Hearing Loss ◽  
Otoacoustic Emissions ◽  
Treatment Protocol ◽  
Pure Tone Audiometry ◽  
Csf Shunt ◽  
Shunt Placement ◽  
Cochlear Aqueduct ◽  
Distortion Product ◽  
Cerebrospinal Fluid Shunting

Object Cerebrospinal fluid shunting has previously been associated with hearing loss. Although the mechanism for this is unclear, it is thought that changes in CSF pressure can affect cochlear physiology via endolymph expansion in the setting of a patent cochlear aqueduct. Patients undergoing radiation and cisplatin chemotherapy are at risk for hearing loss. The authors hypothesized that the incidence and severity of hearing loss in patients undergoing radiation and chemotherapy for medulloblastoma would be greater in those with shunts than in those without shunts. Methods Baseline and longitudinal audiology data were collected in 33 patients with medulloblastoma who were receiving radiation and cisplatin chemotherapy. Additional data included age, sex, details of shunt placement and revision, and details of chemotherapy and radiation. Hearing sensitivity and peripheral auditory function measures included pure tone audiometry, immittance audiometry, and distortion product evoked otoacoustic emissions. Ototoxicity was determined according to the American Speech-Language-Hearing Association criteria. Severity of hearing loss was determined using the Brock hearing loss grades. Incidence of hearing loss and association with shunting was determined. Results Thirteen (39.4%) of the 33 patients evaluated had undergone shunt placement. Hearing loss occurred in 14 (70%) of 20 patients without shunts and in 13 (100%) of 13 patients with shunts. The difference between the rates of hearing loss in patients with shunts versus those without the devices was highly significant (p = 0.0008). The odds ratio for hearing loss in patients with a CSF shunt compared with those without a shunt was 23.49 (95% CI 4.21–131.15). Age, side of shunt, evidence of dissemination, diameter of cochlear aqueduct, and treatment protocol did not have a significant effect on shunt-related ototoxicity. Conclusions This study suggests an independent association between CSF shunting and hearing loss in children undergoing treatment for medulloblastoma, laying the foundation for a prospective study evaluating hearing loss in children with shunts who are not treated with ototoxic therapy.

scholarly journals Frequency matching of vocalizations to inner-ear sensitivity along an altitudinal gradient in the coqui frog

2009 ◽  
Vol 6 (2) ◽  
pp. 278-281 ◽  
Author(s):  
Sebastiaan W. F. Meenderink ◽  
Mirja Kits ◽  
Peter M. Narins
Keyword(s):  
Body Size ◽  
Inner Ear ◽  
Sea Level ◽  
Otoacoustic Emissions ◽  
Altitudinal Gradient ◽  
Distortion Product Otoacoustic Emissions ◽  
Frequency Range ◽  
Frequency Matching ◽  
Distortion Product ◽  
Sensitivity Change

Acoustic communication involves both the generation and the detection of a signal. In the coqui frog ( Eleutherodactylus coqui ), it is known that the spectral contents of its calls systematically change with altitude above sea level. Here, distortion product otoacoustic emissions are used to assess the frequency range over which the inner ear is sensitive. It is found that both the spectral contents of the calls and the inner-ear sensitivity change in a similar fashion along an altitudinal gradient. As a result, the call frequencies and the auditory tuning are closely matched at all altitudes. We suggest that the animal's body size determines the frequency particulars of the call apparatus and the inner ear.

Unilateral Hearing Loss in Children with Shunt-Treated Hydrocephalus

2003 ◽  
Vol 14 (09) ◽  
pp. 510-517 ◽  
Author(s):  
Susan E. Spirakis ◽  
Raymond M. Hurley
Keyword(s):  
Hearing Loss ◽  
High Frequency ◽  
Otoacoustic Emissions ◽  
Pure Tone ◽  
Acoustic Reflex ◽  
Shunt Placement ◽  
Cochlear Aqueduct ◽  
Distortion Product ◽  
Cochlear Hearing Loss ◽  
Air Conduction

This study investigated the characteristics of hearing loss in children with ventriculoperitoneal (VP) shunted hydrocephalus. Twelve hydrocephalic children with patent VP shunts participated. The etiology of the hydrocephalus was either intraventricular hemorrhage or spina bifida. Audiometric examination included pure-tone air conduction thresholds, tympanometry, contralateral and ipsilateral acoustic reflex thresholds (ARTs), and distortion product otoacoustic emissions (DPOAEs). A unilateral, high-frequency, cochlear hearing loss was found in the ear ipsilateral to the shunt placement in 10 (83%) of the 12 shunt-treated hydrocephalic children. No hearing loss was observed in the ear contralateral to shunt placement. Based on the pure-tone audiometric findings, coupled with the decrease in DPOAE amplitude in the shunt ear, the hearing loss appears to be cochlear in nature. We suggest that cochlear hydrodynamics are disrupted as the result of reduced perilymph pressure, a consequence of cerebrospinal fluid (CSF) reduction due to the combined effects of a patent shunt and a patent cochlear aqueduct. In addition, a concomitant brain stem involvement is evidenced in the ART pattern, possibly produced by the patent shunt draining the CSF from the subdural space, resulting in cranial base hypoplasia.

Functional Patency of the Cochlear Aqueduct

1982 ◽  
Vol 91 (2) ◽  
pp. 209-215 ◽  
Author(s):  
Björn Carlborg ◽  
Barbara Densert ◽  
Ove Densert
Keyword(s):  
Cerebrospinal Fluid ◽  
Inner Ear ◽  
Middle Ear ◽  
Ambient Pressure ◽  
Ear Canal ◽  
Cochlear Aqueduct ◽  
Pressure Release ◽  
Release Capacity ◽  
Before And After ◽  
Pressure Changes

The perilymphatic (P P) and cerebrospinal fluid (P CSF) pressures were investigated in relation to pressure variations in the ear canal, middle ear and intracranial compartment before and after occlusion of the cochlear aqueduct (CA). Experiments using intracranial infusion showed that the CA was responsible for a perfect hydrodynamic balance between the CSF and the perilymph. There are indications of additional pressure release factors but their capacities were not sufficient to prevent the appearance of a longstanding and substantial pressure gradient following occlusion of the CA. A gradual P P build-up, from zero to its original level after the CA was opened and occluded, indicated perilymph production within the labyrinth. Investigation of pressure transfer from the ear canal and middle ear to the perilymph showed that the CA was the major pressure release route from the cochlea. Occlusion of the CA reduced the compliance of the inner ear and severely reduced the pressure release capacity. In such a situation the inner ear is almost incapable of equilibrating ambient pressure changes.

Dynamics of Inner Ear Pressure Change Caused by Intracranial Pressure Manipulation in the Guinea Pig

2001 ◽  
Vol 121 (4) ◽  
pp. 470-476 ◽  
Author(s):  
E.O. Thalen ◽  
H.P. Wit ◽  
J.M. Segenhout ◽  
F.W.J. Albers
Keyword(s):  
Intracranial Pressure ◽  
Guinea Pig ◽  
Inner Ear ◽  
Pressure Change ◽  
Inner Ear Pressure

Intracranial Pressure Modulates Distortion Product Otoacoustic Emissions

Neurosurgery ◽  
2014 ◽  
Vol 75 (4) ◽  
pp. 445-455 ◽  
Author(s):  
Eric M. Bershad ◽  
Mian Z. Urfy ◽  
Alina Pechacek ◽  
Mary McGrath ◽  
Eusebia Calvillo ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Otoacoustic Emissions ◽  
Permutation Test ◽  
Distortion Product Otoacoustic Emissions ◽  
New Approach ◽  
Future Studies ◽  
Distortion Product ◽  
Novel Approach ◽  
Opening And Closing ◽  
First Time

Abstract BACKGROUND: There is an important need to develop a noninvasive method for assessing intracranial pressure (ICP). We report a novel approach for monitoring ICP using cochlear-derived distortion product otoacoustic emissions (DPOAEs), which are affected by ICP. OBJECTIVE: We hypothesized that changes in ICP may be reflected by altered DPOAE responses via an associated change in perilymphatic pressure. METHODS: We measured the ICP and DPOAEs (magnitude and phase angle) during opening and closing in 20 patients undergoing lumbar puncture. RESULTS: We collected data on 18 patients and grouped them based on small (<4 mm Hg), medium (5–11 mm Hg), or large (≥15 mm Hg) ICP changes. A permutation test was applied in each group to determine whether changes in DPOAEs differed from zero when ICP changed. We report significant changes in the DPOAE magnitudes and angles, respectively, for the group with the largest ICP changes and no changes for the group with the smallest changes; the group with medium changes had variable DPOAE changes. CONCLUSION: We report, for the first time, systematic changes in DPOAE magnitudes and phase in response to acute ICP changes. Future studies are warranted to further develop this new approach.

Lymphocytic Streaming as an Indicator of Inner Ear Compartmentalization

1981 ◽  
Vol 89 (5) ◽  
pp. 836-840
Author(s):  
George Roffman ◽  
Richard W. Babin
Keyword(s):  
Central Nervous System ◽  
Cerebrospinal Fluid ◽  
Nervous System ◽  
Inner Ear ◽  
Lymphoblastic Leukemia ◽  
Cochlear Aqueduct ◽  
Fluid Channel ◽  
Temporal Bones ◽  
Perilymphatic Space ◽  
Physiologic Data

Despite a great deal of anatomic and physiologic data in animals, controversy still exists over whether or not the perilymphatic space in man is directly connected to the intracranial space via a patent cochlear aqueduct or other fluid channel. Human physiologic data are limited, indirect, and conflicting. Anatomic and pathologic data have heretofor been inadequate for answering the question convincingly. The temporal bones of a 19-year-old woman with central nervous system lymphoblastic leukemia are discussed. The passive-appearing movement of lymphoblasts between cerebrospinal fluid and perilymphatic spaces suggests both a functionally patent cochlear aqueduct and alternate pathways.

Dynamics of Inner Ear Pressure Change Caused by Intracranial Pressure Manipulation in the Guinea Pig

2001 ◽  
Vol 121 (4) ◽  
pp. 470-476 ◽  
Author(s):  
E.O. Thalen ◽  
H.P. Wit ◽  
J.M. Segenhout ◽  
F.W.J. Albers
Keyword(s):  
Intracranial Pressure ◽  
Guinea Pig ◽  
Inner Ear ◽  
Pressure Change ◽  
Inner Ear Pressure
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