The electric response of the cochlear hair cells to acoustic stimulation.
The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.
Use of sound to elicit a response in the nervous system.
The fluid separating the membranous labyrinth from the osseous labyrinth of the ear. It is entirely separate from the ENDOLYMPH which is contained in the membranous labyrinth. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1396, 642)
The lower chamber of the COCHLEA, extending from the round window to the helicotrema (the opening at the apex that connects the PERILYMPH-filled spaces of scala tympani and SCALA VESTIBULI).
The lymph fluid found in the membranous labyrinth of the ear. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Electrodes which can be used to measure the concentration of particular ions in cells, tissues, or solutions.
Fluids found within the osseous labyrinth (PERILYMPH) and the membranous labyrinth (ENDOLYMPH) of the inner ear. (From Gray's Anatomy, 30th American ed, p1328, 1332)
Sensory cells in the organ of Corti, characterized by their apical stereocilia (hair-like projections). The inner and outer hair cells, as defined by their proximity to the core of spongy bone (the modiolus), change morphologically along the COCHLEA. Towards the cochlear apex, the length of hair cell bodies and their apical STEREOCILIA increase, allowing differential responses to various frequencies of sound.
Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.
The complex series of phenomena, occurring between the end of one CELL DIVISION and the end of the next, by which cellular material is duplicated and then divided between two daughter cells. The cell cycle includes INTERPHASE, which includes G0 PHASE; G1 PHASE; S PHASE; and G2 PHASE, and CELL DIVISION PHASE.
A protein-serine-threonine kinase that is activated by PHOSPHORYLATION in response to GROWTH FACTORS or INSULIN. It plays a major role in cell metabolism, growth, and survival as a core component of SIGNAL TRANSDUCTION. Three isoforms have been described in mammalian cells.
A cell line derived from cultured tumor cells.
Conditions caused by abnormal CILIA movement in the body, usually causing KARTAGENER SYNDROME, chronic respiratory disorders, chronic SINUSITIS, and chronic OTITIS. Abnormal ciliary beating is likely due to defects in any of the 200 plus ciliary proteins, such as missing motor enzyme DYNEIN arms.
A mitogen-activated protein kinase subfamily that is widely expressed and plays a role in regulation of MEIOSIS; MITOSIS; and post mitotic functions in differentiated cells. The extracellular signal regulated MAP kinases are regulated by a broad variety of CELL SURFACE RECEPTORS and can be activated by certain CARCINOGENS.
Electronic hearing devices typically used for patients with normal outer and middle ear function, but defective inner ear function. In the COCHLEA, the hair cells (HAIR CELLS, VESTIBULAR) may be absent or damaged but there are residual nerve fibers. The device electrically stimulates the COCHLEAR NERVE to create sound sensation.
Hearing loss in frequencies above 1000 hertz.
A form of electrophysiologic audiometry in which an analog computer is included in the circuit to average out ongoing or spontaneous brain wave activity. A characteristic pattern of response to a sound stimulus may then become evident. Evoked response audiometry is known also as electric response audiometry.
Hearing loss due to exposure to explosive loud noise or chronic exposure to sound level greater than 85 dB. The hearing loss is often in the frequency range 4000-6000 hertz.
Surgical insertion of an electronic hearing device (COCHLEAR IMPLANTS) with electrodes to the COCHLEAR NERVE in the inner ear to create sound sensation in patients with residual nerve fibers.
The process whereby an utterance is decoded into a representation in terms of linguistic units (sequences of phonetic segments which combine to form lexical and grammatical morphemes).
The perceived attribute of a sound which corresponds to the physical attribute of intensity.
A subspecialty of otolaryngology dealing with the parts of the nervous system related to the ear.
The study of hearing and hearing impairment.
The study of speech or language disorders and their diagnosis and correction.
Conditions that impair the transmission of auditory impulses and information from the level of the ear to the temporal cortices, including the sensorineural pathways.
Publications in any medium issued in successive parts bearing numerical or chronological designations and intended to be continued indefinitely. (ALA Glossary of Library and Information Science, 1983, p203)
Part of an ear examination that measures the ability of sound to reach the brain.
A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of COCHLEAR DISEASES; VESTIBULOCOCHLEAR NERVE DISEASES; INTRACRANIAL HYPERTENSION; CRANIOCEREBRAL TRAUMA; and other conditions.
Development of lesions in the lymph node characterized by infiltration of the cortex or paracortex by large collections of proliferating histiocytes and complete or, more often, incomplete necrosis of lymphoid tissue.
A layer of stratified EPITHELIUM forming the endolymphatic border of the cochlear duct at the lateral wall of the cochlea. Stria vascularis contains primarily three cell types (marginal, intermediate, and basal), and capillaries. The marginal cells directly facing the ENDOLYMPH are important in producing ion gradients and endochoclear potential.
A spiral thickening of the fibrous lining of the cochlear wall. Spiral ligament secures the membranous COCHLEAR DUCT to the bony spiral canal of the COCHLEA. Its spiral ligament fibrocytes function in conjunction with the STRIA VASCULARIS to mediate cochlear ion homeostasis.
The spiral EPITHELIUM containing sensory AUDITORY HAIR CELLS and supporting cells in the cochlea. Organ of Corti, situated on the BASILAR MEMBRANE and overlaid by a gelatinous TECTORIAL MEMBRANE, converts sound-induced mechanical waves to neural impulses to the brain.
The essential part of the hearing organ consists of two labyrinthine compartments: the bony labyrinthine and the membranous labyrinth. The bony labyrinth is a complex of three interconnecting cavities or spaces (COCHLEA; VESTIBULAR LABYRINTH; and SEMICIRCULAR CANALS) in the TEMPORAL BONE. Within the bony labyrinth lies the membranous labyrinth which is a complex of sacs and tubules (COCHLEAR DUCT; SACCULE AND UTRICLE; and SEMICIRCULAR DUCTS) forming a continuous space enclosed by EPITHELIUM and connective tissue. These spaces are filled with LABYRINTHINE FLUIDS of various compositions.
A disease of the inner ear (LABYRINTH) that is characterized by fluctuating SENSORINEURAL HEARING LOSS; TINNITUS; episodic VERTIGO; and aural fullness. It is the most common form of endolymphatic hydrops.
The hearing and equilibrium system of the body. It consists of three parts: the EXTERNAL EAR, the MIDDLE EAR, and the INNER EAR. Sound waves are transmitted through this organ where vibration is transduced to nerve signals that pass through the ACOUSTIC NERVE to the CENTRAL NERVOUS SYSTEM. The inner ear also contains the vestibular organ that maintains equilibrium by transducing signals to the VESTIBULAR NERVE.
A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.
The space and structures directly internal to the TYMPANIC MEMBRANE and external to the inner ear (LABYRINTH). Its major components include the AUDITORY OSSICLES and the EUSTACHIAN TUBE that connects the cavity of middle ear (tympanic cavity) to the upper part of the throat.
A general term for the complete or partial loss of the ability to hear from one or both ears.
Exclusive legal rights or privileges applied to inventions, plants, etc.
The motion of air relative to the earth's surface.
Materials or phenomena which can provide energy directly or via conversion.
Self-generated faint acoustic signals from the inner ear (COCHLEA) without external stimulation. These faint signals can be recorded in the EAR CANAL and are indications of active OUTER AUDITORY HAIR CELLS. Spontaneous otoacoustic emissions are found in all classes of land vertebrates.
A type of non-ionizing radiation in which energy is transmitted through solid, liquid, or gas as compression waves. Sound (acoustic or sonic) radiation with frequencies above the audible range is classified as ultrasonic. Sound radiation below the audible range is classified as infrasonic.
Forms of energy that are constantly and rapidly renewed by natural processes such as solar, ocean wave, and wind energy. (from McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Units that convert some other form of energy into electrical energy.
An amino acid that, as the D-isomer, is the defining agonist for the NMDA receptor subtype of glutamate receptors (RECEPTORS, NMDA).
Cell surface proteins that bind amino acids and trigger changes which influence the behavior of cells. Glutamate receptors are the most common receptors for fast excitatory synaptic transmission in the vertebrate central nervous system, and GAMMA-AMINOBUTYRIC ACID and glycine receptors are the most common receptors for fast inhibition.
Endogenous amino acids released by neurons as excitatory neurotransmitters. Glutamic acid is the most common excitatory neurotransmitter in the brain. Aspartic acid has been regarded as an excitatory transmitter for many years, but the extent of its role as a transmitter is unclear.
Discussion of documents issued by local, regional, or national governments or by their agencies or subdivisions.
Books designed by the arrangement and treatment of their subject matter to be consulted for definite terms of information rather than to be read consecutively. Reference books include DICTIONARIES; ENCYCLOPEDIAS; ATLASES; etc. (From the ALA Glossary of Library and Information Science, 1983)
A class of ionotropic glutamate receptors characterized by affinity for N-methyl-D-aspartate. NMDA receptors have an allosteric binding site for glycine which must be occupied for the channel to open efficiently and a site within the channel itself to which magnesium ions bind in a voltage-dependent manner. The positive voltage dependence of channel conductance and the high permeability of the conducting channel to calcium ions (as well as to monovalent cations) are important in excitotoxicity and neuronal plasticity.

Supporting cells contribute to control of hearing sensitivity. (1/77)

The mammalian hearing organ, the organ of Corti, was studied in an in vitro preparation of the guinea pig temporal bone. As in vivo, the hearing organ responded with an electrical potential, the cochlear microphonic potential, when stimulated with a test tone. After exposure to intense sound, the response to the test tone was reduced. The electrical response either recovered within 10-20 min or remained permanently reduced, thus corresponding to a temporary or sustained loss of sensitivity. Using laser scanning confocal microscopy, stimulus-induced changes of the cellular structure of the hearing organ were simultaneously studied. The cells in the organ were labeled with two fluorescent probes, a membrane dye and a cytoplasm dye, showing enzymatic activity in living cells. Confocal microscopy images were collected and compared before and after intense sound exposure. The results were as follows. (1) The organ of Corti could be divided into two different structural entities in terms of their susceptibility to damage: an inner, structurally stable region comprised of the inner hair cell with its supporting cells and the inner and outer pillar cells; and an outer region that exhibited dynamic structural changes and consisted of the outer hair cells and the third Deiters' cell with its attached Hensen's cells. (2) Exposure to intense sound caused the Deiters' cells and Hensen's cells to move in toward the center of the cochlear turn. (3) This event coincided with a reduced sensitivity to the test tone (i.e., reduced cochlear microphonic potential). (4) The displacement and sensitivity loss could be reversible. It is concluded that these observations have relevance for understanding the mechanisms behind hearing loss after noise exposure and that the supporting cells take an active part in protection against trauma during high-intensity sound exposure.  (+info)

The effects of tone exposure on the inner ear functions in the guinea pig: impact tone vs. steady state tone. (2/77)

The damage-risk criterion (DRC) for hearing supposes that sound exposure with equal energy implies equal risk for noise-induced hearing loss (NIHL). We measured cochlear microphonics (CM), compound action potential (CAP), endocochlear potential (EP) and K+ ion concentration in the scala media, to see if the same level of Leq24h (impact tone and steady state tone) induced the same physiological changes in the inner ear function or not. Regarding the equal energy principle (EEP), we also examined if the EEP is appropriate or not at exposure of moderate level tone. We also checked how the time interval between impact tones affects or not the inner ear functions at the same Leq24h tone exposure. Therefore we used exposure at 1 pulse/second or 1 pulse/3 seconds and steady state tone exposure at Leq24h=90, 85 and 80 dB. The results are the following. Both steady state and impact tone exposure causes change of the electrophysiological data. First, CM maximum output voltage after exposure to impact tone of 115 dB (Leq24h=90 dB) was lower than after exposure to a 8 kHz steady state tone of 90 dB. CAP threshold (below 10 microV) obtained after the 115 and 110 dB exposure of impact tone were 5-10 dB higher than that of steady state tone of 90 dB. The negative EP induced by impact tone exposures showed the same tendency as the CM experiments. Having more frequent pulses (1 pulse/second vs. to 1 pulse/3 seconds) showed more inhibition. The K+ concentration time course remained similar to the control when the Leq24h was low (80 dB). Impact tone exposure induced stronger effects to the inner ear at exposure of moderate level tone than that of steady state tone of Leq24h.  (+info)

Comparative study of effects of impact tone and steady state tone exposure: EP and concentration of K+ ion and Na+ ion. (3/77)

To test the adequacy of equal energy principle (EEP), guinea pigs were exposed to impact tone. The changes in electrophysiological data, namely endocochlear potential (EP) and the change in K+ ion and Na+ ion concentrations in the endolymph were investigated. The frequency of impact tone was 1 pulse/second or 1 pulse/3 seconds. The steady state tone had Leq24h = 100, 95, 90 or 85 dB, and impact tone had Leq24h = 95, 90 or 85 dB. The results are the following. Both steady state and impact tone exposure cause changes of electrophysiological data. The effects on the absolute value of negative EP induced by impact tone exposures were smaller than that of steady state tone of the same Leq. The rate of pulses was also an important factor for impact tone exposure. Impact tone exposure of 1 pulse/second caused smaller absolute value of negative EP than that of 1 pulse/3 seconds. The K+ ion concentration time course in the endolymph remained similar to the control (Exp. 1) only in Exp. 8 (85 dB; the lowest steady state noise exposure in our experiments), but no decrease in the K+ ion concentration was detected in the other experiments, suggesting an alteration in the K+ ion flow. The Na+ ion concentration time course was also influenced showing no increase in Na+ ion concentration compared to the control (Exp. 1c) and the lowest steady-state exposure experiment (Exp. 8c). Our experimental results suggest that both the K+ ion and Na+ ion movement are altered by tone exposure. We found also that the different types of noise exposure with the same Leq value does not exhibit the same changes. Leq24h is not an accurate damage risk criteria.  (+info)

A targeted deletion in alpha-tectorin reveals that the tectorial membrane is required for the gain and timing of cochlear feedback. (4/77)

alpha-tectorin is an extracellular matrix molecule of the inner ear. Mice homozygous for a targeted deletion in a-tectorin have tectorial membranes that are detached from the cochlear epithelium and lack all noncollagenous matrix, but the architecture of the organ of Corti is otherwise normal. The basilar membranes of wild-type and alpha-tectorin mutant mice are tuned, but the alpha-tectorin mutants are 35 dB less sensitive. Basilar membrane responses of wild-type mice exhibit a second resonance, indicating that the tectorial membrane provides an inertial mass against which outer hair cells can exert forces. Cochlear microphonics recorded in alpha-tectorin mutants differ in both phase and symmetry relative to those of wild-type mice. Thus, the tectorial membrane ensures that outer hair cells can effectively respond to basilar membrane motion and that feedback is delivered with the appropriate gain and timing required for amplification.  (+info)

KCNJ10 (Kir4.1) potassium channel knockout abolishes endocochlear potential. (5/77)

Stria vascularis of the cochlea generates the endocochlear potential and secretes K(+). K(+) is the main charge carrier and the endocochlear potential the main driving force for the sensory transduction that leads to hearing. Stria vascularis consists of two barriers, marginal cells that secrete potassium and basal cells that are coupled via gap junctions to intermediate cells. Mice lacking the KCNJ10 (Kir4.1) K(+) channel in strial intermediate cells did not generate an endocochlear potential. Endolymph volume and K(+) concentration ([K(+)]) were reduced. These studies establish that the KCNJ10 K(+) channel provides the molecular mechanism for generation of the endocochlear potential in concert with other transport pathways that establish the [K(+)] difference across the channel. KCNJ10 is also a limiting pathway for K(+) secretion.  (+info)

Loud sound-induced changes in cochlear mechanics. (6/77)

To investigate the inner ear response to intense sound and the mechanisms behind temporary threshold shifts, anesthetized guinea pigs were exposed to tones at 100-112 dB SPL. Basilar membrane vibration was measured using laser velocimetry, and the cochlear microphonic potential, compound action potential of the auditory nerve, and local electric AC potentials in the organ of Corti were used as additional indicators of cochlear function. After exposure to a 12-kHz intense tone, basilar membrane vibrations in response to probe tones at the characteristic frequency of the recording location (17 kHz) were transiently reduced. This reduction recovered over the course of 50 ms in most cases. Organ of Corti AC potentials were also reduced and recovered with a time course similar to the basilar membrane. When using a probe tone at either 1 or 4 kHz, organ of Corti AC potentials were unaffected by loud sound, indicating that transducer channels remained intact. In most experiments, both the basilar membrane and the cochlear microphonic response to the 12-kHz overstimulation was constant throughout the duration of the intense stimulus, despite a large loss of cochlear sensitivity. It is concluded that the reduction of basilar membrane velocity that followed loud sound was caused by changes in cochlear amplification and that the cochlear response to intense stimulation is determined by the passive mechanical properties of the inner ear structures.  (+info)

NompC TRP channel required for vertebrate sensory hair cell mechanotransduction. (7/77)

The senses of hearing and balance in vertebrates rely on the sensory hair cells (HCs) of the inner ear. The central element of the HC's transduction apparatus is a mechanically gated ion channel of unknown identity. Here we report that the zebrafish ortholog of Drosophila no mechanoreceptor potential C (nompC), which encodes a transient receptor potential (TRP) channel, is critical for HC mechanotransduction. In zebrafish larvae, nompC is selectively expressed in sensory HCs. Morpholino-mediated removal of nompC function eliminated transduction-dependent endocytosis and electrical responses in HCs, resulting in larval deafness and imbalance. These observations indicate that nompC encodes a vertebrate HC mechanotransduction channel.  (+info)

Stiffness of the gerbil basilar membrane: radial and longitudinal variations. (8/77)

Experimental data on the mechanical properties of the tissues of the mammalian cochlea are essential for understanding the frequency- and location-dependent motion patterns that result in response to incoming sound waves. Within the cochlea, sound-induced vibrations are transduced into neural activity by the organ of Corti, the gross motion of which is dependent on the motion of the underlying basilar membrane. In this study we present data on stiffness of the gerbil basilar membrane measured at multiple positions within a cochlear cross section and at multiple locations along the length of the cochlea. A basic analysis of these data using relatively simple models of cochlear mechanics reveals our most important result: the experimentally measured longitudinal stiffness gradient at the middle of the pectinate zone of the basilar membrane (4.43 dB/mm) can account for changes of best frequency along the length of the cochlea. Furthermore, our results indicate qualitative changes of stiffness-deflection curves as a function of radial position; in particular, there are differences in the rate of stiffness growth with increasing tissue deflection. Longitudinal coupling within the basilar membrane/organ of Corti complex is determined to have a space constant of 21 microm in the middle turn of the cochlea. The bulk of our data was obtained in the hemicochlea preparation, and we include a comparison of this set of data to data obtained in vivo.  (+info)

It has been estimated that over one third of subjects with AN are affected by peripheral neuropathies [6]. In addition, optic neuropathies and other CNS disorders have been found in association with AN (non-isolated AN, Table 1). In this group of subjects the hearing disorder is underlain by several genetic defects, all resulting in neuronal loss and demyelination in peripheral and/or cranial nerves, and the site of the lesion is invariably postsynaptic.. AN has been identified at relatively high frequency in patients affected by Charcot-Marie-Tooth (CMT) disease. The first gene associated with AN in this group was the myelin protein zero (MPZ) gene [24] encoding a protein included in the compact myelin that plays a crucial role in myelin formation and adhesion. A missense mutation in MPZ was identified in a family affected by dominant AN and demyelinating sensorimotor neuropathy [24]. Post-mortem examination carried out on one member of this family revealed preserved hair cells in the cochlea, ...
Assessments of CAP amplitude (Fig. 2) and intraaxonal dye diffusion (Fig. 3) show that direct application of PEG to crush-severed sciatic nerves usually (97% of all attempts) rapidly restores physiological and morphological continuity to at least some axons in the sciatic nerve. In fact, continuity may be restored to many proximal and distal axonal halves (with unknown specificity) since CAP amplitudes of PEG-fused nerves on average are 50 to 89% of CAP amplitudes of intact-control or sham-operated nerves. FF asymmetry scores (Fig. 4) provide quantitative assessment of hindlimb motor behavior and show significantly faster recovery of functional behavior associated with direct application of PEG to crush-severed sciatic nerves. This finding for FF asymmetry scores is consistent with our measures of physiological and morphological continuity.. Video observations of FF trials and of open field trials also show rapid behavioral improvement associated with direct application of PEG to crush-severed ... Researchers at Harvard Medical Schools Eaton Peabody Laboratory learned you can lose up to 90 percent of your cochlear nerve fibers from frequent earbud use. Now hear this: Earbud headphones, even at low volume, may be causing permanent damage to your hearing. For decades, scientists have looked, almost exclusively, at the loss of…
Many cephalopods have lines of ciliated cells on their head and arms. In the cuttlefish Sepia and the squid Lolliguncula, electrophysiological recordings clearly identify these epidermal lines as an...
A string instrument pickup system sensitive to 360 of transverse string movement, which is substantially immune from microphonics, and which has a substantially equal or balanced response to all of the strings. In one form of the invention a piezoelectric transducer is compressively associated with vertical movement components of each string of the instrument, but is laterally offset from a centered position under the string for compressive association of the transducer also with the horizontal string movement components; and halves of the total piezoelectric transducer area are oppositely polarized so as to cancel out microphonics. In a modular form of the invention a plurality of the piezoelectric transducers are supported in an elongated array by means of a flexible body of electrically insulative material and a pliable outer wrapping of metal foil so that the transducer is conformable to distortions and deformations in string saddle and bridge elements of the instrument between which the modular
Mice homozygous for the jerker spontaneous mutation (|i|Espn|sup|je|/sup||/i|) show behavior typical of the circling mutants - head-tossing, circling, and hyperactivity. Homozygous mutant mice are deaf from birth and have no detectable stimulus-related cochlear potential at any stage. The abnormal behavior and deafness are associated with postnatal degeneration of the sensory cells of the cochlea and the sacculus and utriculus in homozygotes. The primary influence of the jerker gene appears to be on the apical hair cells, not development of neural structures. Heterozygous jerker mice undergo a similar type of degeneration, but the onset is delayed. Auditory brainstem response is totally absent in homozygotes while heterozygous mice undergo a progressive impairment with age.|br||br|Flexed tail homozygotes can be identified hematologically as earlyas embryonic day 13 and are detectably paler than normal by embryonic day 16, with most paler than normal by embryonic day 15. Homozygotes are small at birth
Canton has recently introduced eight new loudspeakers in its Ergo line, including a new powered subwoofer and seven full-range models featuring new crossover. New models include a trio of three-way floorstanders, two bookshelf speakers, two 2-1/2-way center channel speakers, and a 200-Watt powered subwoofer, and all are available in silver lacquer, black, beech, and cherry wood veneer finishes. The new Ergo full-range models incorporate improved crossover networks that are based on technology developed for the companys signature Karat Reference 2 DC loudspeaker system. These changes include the use of ICW polypropylene capacitors, which have led to a marked reduction in dielectric absorption or memory effects giving the models improved transient response and detail. The new crossover design also has a significant reduction in microphonics designed to improve mid-range and high-frequency reproduction. The new Ergo center channel speakers are 2-1/2-way designs optimized for horizontal mounting. ...
Subject: biophysics of infrasound From: Eliot Handelman ,eliot(at)SUNRISE.CC.MCGILL.CA, Date: Thu, 27 Jan 1994 17:19:34 EST Greetings, Im trying to locate research on the biophysical effects of infrasound. A few years ago I collected a series of citations -- about 25? from JASA, primarily from the late 50s and early 60s. Princeton cataloged several of these but they were all missing. It turned out that these papers were reclassified during 80s, and my efforts to get them through the DoD met with no success, supposedly because Princeton did not wish to comply with Dods restricted materials protocol. Can anyone tell me what is so interesting about biophysical effects of infrasound that merits classification? Best, -- eliot ...
Cochlear-Internal Carotid Artery Dehiscence with a Pathologic Electrocochleography Dehiscences of labyrinthine structures are mainly defects of the semicircular canals. ..
Starting in 2011, infrasound sensors became a standard component and were installed at each new USArray Transportable Array (TA) site. Currently, with over 400 sensors, TA acts as a large infrasound array that continuously samples the wavefield of atmospheric acoustic sources. To support this new data set, the IRIS Data Management Center (DMC) has developed two infrasound data products: the TA Infrasound Reference Event Database (TAIRED) and TA Infrasound Detections (TAID). These two data products are designed to provide insight and tools for researchers to begin working with this large, and somewhat unique, new data set.. TAIRED ( is a user-supported evolving infrasound reference event depository where researchers can contribute to and find infrasound events for their research. This database currently holds 59 events including one meteorite, seven explosions, and 12 rocket launches. For each event, metadata, infrasound and seismic record sections, ...
The cochlear stria vascularis produces the positive endocochlear potential (EP) and the endolymph. Both the EP and the endolymph are essential for the physiological function of hair cells. The interme
Peripheral neural responses to cochlear stimulation via electrically evoked compound action potentials (ECAPs) of differing pulse distance and interphase gap
Fish possess two separate systems for detection of low-level sound and water motions in the low-frequency range: the inner ear and the lateral line. The relative roles of these systems in normal fish behaviour is still not clear. There is, for instance, a lack of experimental evidence showing the involvement of the lateral line and the inner ear in detection of infrasound, in directional hearing in the near field, and in detection and attack of swimming prey below the surface. To provide a useful tool for such studies, we have developed a pharmacological method for selective and reversible blocking of the lateral line in the roach (Rutilus rutilus). By recording multi-unit activity from the lateral line nerve and microphonic potentials from the inner ear, we have shown that cobalt ions in the external water may completely block the mechanosensitivity of the lateral line without affecting the utricular microphonic activity. This inhibiting effect of Co2+ is antagonized by Ca2+, making the ratio ...
Synonyms for Acoustic reflex in Free Thesaurus. Antonyms for Acoustic reflex. 26 synonyms for reflex: automatic, spontaneous, instinctive, involuntary, impulsive, knee-jerk, unthinking, automatic, impulsive, instinctive, involuntary.... What are synonyms for Acoustic reflex?
The AMA Fee Navigator™ is an enhanced, easy-to-use version of the Schedule of Medical Benefits supplemented by expert, trusted AMA billing advice and tips.
Select-A-Strike clappers are adjustable by rotating the clapper screw slightly counter-clockwise until the clapper is free to rotate. Rotate the clapper to the desired position and retighten the screw.. Quick-Adjust clappers (See Fig. 3) are adjustable without loosening the clapper screw. In fact, the clapper screw should never be turned. This screw is locked to the clapper shaft by a special chemical bond between the screw and shaft. To adjust, rotate clapper until it clicks into the desired position. NOTE: DO NOT TAKE YOUR QUICK-ADJUST CLAPPER APART. THEY MUST BE RETURNED TO THE FACTORY FOR ANY REPAIRS NEEDED.. Try it! On all bells C8 and below in pitch, three decidedly different impact tones can be achieved. This permits a selection of mellow or more brilliant tones to be generated in your bells, according to your tonal preference. These options provide a soft mellow strike tone designated by the letter S imprinted on the clapper insert, a medium tone designated by M on the insert, and ...
Below about 50 kHz the level of ambient noise in the sea increases continuously towards lower frequencies. In the infrasound range the spectral slope is particularly steep. This low-frequency noise may propagate long distances with little attenuation, causing a directional pattern of infrasound in the sea. Using a standing-wave acoustic tube, we have studied the sensitivity of cod to infrasound down to 0.1 Hz by means of the cardiac conditioning technique. The threshold values, measured as particle acceleration, showed a steady decline towards lower frequencies below 10 Hz, reaching a value close to 10(−5)ms-2 at 0.1 Hz. The spectrum level at 0.1 Hz in the sea ranges between 120 and 180 dB (re 1 microPa), with corresponding particle accelerations from less than 10(−6) to more than 10(−4)ms-2. The sensitivity of cod is thus sufficient to detect the highest levels of ambient infrasound, and we put forward the hypothesis that fish may utilize information about the infrasound pattern in the ...
Definition of acoustic reflex threshold in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is acoustic reflex threshold? Meaning of acoustic reflex threshold as a finance term. What does acoustic reflex threshold mean in finance?
TY - JOUR. T1 - Intracellular Potential Changes of Cortis Organ With Anoxia. AU - Nuttall, Alfred L.. AU - Lawrence, Merle. PY - 1979/10. Y1 - 1979/10. N2 - Intracellular measurements of the resting cell membrane potentials of guinea pig Cortis organ were made in order to determine the sensitivity of this cell potential to anoxic hypoxia (a lowered oxygen state due to lack of respiratory oxygen) and to establish differences according to cell types or morphologic regions of the sensory epithelium. The negative cell potentials measured from successful electrode penetrations were found to be relatively more stable and resistant to change during a 120-s period of anoxia than was the positive endocochlear potential. The intracellular resting potentials were also much slower to recover after resumption of respiration. Data obtained from various cells in two different regions of Cortis organ indicate that Cortis organ is receiving oxygen from both the perilymph and the endolymph. An iontophoretic ...
Auditory evoked potentials (AEP) are highly demanded during the whole process of equipping patients with cochlear implants (CI). They play an essential role in preoperative diagnostics, intraoperative testing, and postoperative monitoring of auditory performance and success. The versatility of AEPs is essentially enhanced by their property to be evokable by acoustic as well as electric stimuli. Thus, the electric responses of the auditory system following acoustic stimulation and recorded by the conventional surface technique as well as by transtympanic derivation from the promontory (Electrocochleography [ECochG]) are used for the quantitative determination of hearing loss and, additionally, electrically evoked compound actions potentials (ECAP) can be recorded with the intracochlear electrodes of the implant just adjacent to the stimulation electrode to check the functional integrity of the device and its coupling to the auditory system ...
The MS4630B is suitable for electronics production lines demanding fast and accurate device measurements. It is particularly well suited to accurate, high-speed evaluation of IF filter resonance and group delay characteristics, among others.
A feverish quest exists to uncover the events that lead to cochlear amplification in mammals. The role of the OHC is certainly paramount, and we now have identified many componentsthat form the basis of the cells unique contribution. In my mind, a few observations leadthe story on this hot topic, including the molecular identification of the OHC motor, its modulation by anions and the demonstration of the motors anion transport capabilities. Here I review some of this recent work.. ...
Offered inÂ- 10-67 GHz models, R&S ZVAX-TRM conditions signals from R&S ZVA network analyzers and returns them to analyzer or outputs them via integrated test ports. Users can measure parameters such as compression, noise figure, and group delay, even on 3-port T/R modules, with DUT having to be connected only once. When combined with 4-port analyzer with 4 internal sources,... Read More » ...
Hand Tools, including DEWALT - 23-Piece 1/2 Drive Combination Socket Set DWMT73813, Wilton - 746 Mechanics Vice, DEWALT - Compound Action..
Plants to 1.5 cm high, in hoary green to gray-green cushions, opaque-green to nearly black below. Leaves loosely imbricate when dry, loosely erect-spreading when moist, somewhat concave but not at all keeled, to 3 mm long with the awn constituting nearly 1/2 of that length, ovate-lanceolate from a loosely sheathing somewhat expanded base, 2.5-3.5: 1. Median leaf cells in regular longitudinal rows, unistratose in the expanded base but uniformly bistratose in the limb, smooth, to 7 µm wide, isodiametric with lumens irregular but without corner thickenings. Marginal cells not differentiated. Basal juxtacostal cells elliptical, to 3: 1, to 15 µm wide, with irregularly thickened lateral walls. Basal marginal cells transversely elongate, 0.5-0.7: 1, to 15 µm wide. Costa flared at the base and filling 1/3-1/4 of immediate leaf base, narrowed and obscure above, percurrent in the somewhat acuminate awn. Costa cross-section at leaf middle broad and flattened, less than 1.5 times as thick as the ...
I just started to use VNA. After I done a full insertable 2 port calibration with SMA cable. I measured group delay with port 1 and port 2 reference plane
Fingerprint Dive into the research topics of Porosity controls spread of excitation in tectorial membrane traveling waves. Together they form a unique fingerprint. ...
Although outer hair cells (OHCs) play a key role in cochlear amplification, it is not fully understood how they amplify sound signals by more than 100 fold. Two competing or possibly complementary mechanisms, stereocilia-based and somatic electromotility-based amplification, have been considered. Lacking knowledge about the exceptionally rich protein networks in the OHC plasma membrane, as well as related protein-protein interactions, limits our understanding of cochlear function. Therefore, we focused on finding protein partners for two important membrane proteins: Cadherin 23 (cdh23) and prestin. Cdh23 is one of the tip-link proteins involved in transducer function, a key component of mechanoelectrical transduction and stereocilia-based amplification. Prestin is a basolateral membrane protein responsible for OHC somatic electromotility. Using the membrane-based yeast two-hybrid system to screen a newly built cDNA library made predominantly from OHCs, we identified two completely different groups of
18 yrs old Female asked about Auditory neuropathy, 1 doctor answered this and 67 people found it useful. Get your query answered 24*7 only on | Practo Consult
Impaired stria vascularis integrity upon loss of E cadherin in basal cells is an eagle-i resource of type Journal article at eagle-i Network Shared Resource Repository.
Grant finansowany przez: The J. William Fulbright Foreign Scholarship Board & The U.S. Department of State Nr P008/00 (2000-2001) - Kierownik Projektu i Główny Wykonawca Identifying in an Animal Model Criteria for the Intraoperative Monitoring of Cochlear Function During Neuro-Otologic Surgery in Patients with Cerebello-Pontine Angle Tumors Using Otoacoustic Emissions ...
The key to keeping your chinchilla healthy is to give it a balanced diet. And hay is one of the most ideal foods for chinchilla, which contributes a lot of
differences in human TM waves relative to those of other mammals.. TM wave properties were measured in samples taken from human cadavers ...
Can. J. Bot. 44: 609. 1966. -- Merceya latifoia Kindb. in Mac., Bull. Torr. Bot. Club 16: 94. 1889. -- Scopelophila latifolia (Kindb.) Ren. & Card., Rev. Bryol. 19: 92. 1892. Plants in thick turfs or as scattered tufts to 2.5 cm high, dark-green mostly with a reddish-brown cast. Leaves in a comose apical cluster, spreading when moist but keeled along costa and loosely reflexed near margins when dry, obovate to spatulate, 3.5-4.5 mm long, about 2.5: 1. Median laminal cells pluripapillose with low and inconspicuous punctiform papillae, to 16 µm broad, in straight rows radiating from costa to leaf margin, with lumen/wall ratio 4-8: 1, quadrate to hexagonal with angular lumens and without corner thickenings. Basal juxtacostal cells rectangular with straight and thin lateral walls, to 30 µm broad, 2-5: 1, smooth. Marginal cells abruptly larger than median cells, about twice as deep as wide, mostly reddish pigmented, less papillose and thicker-walled than adjacent laminal cells. Basal marginal cells ...
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Looking for online definition of Auditory Neuropathy, Autosomal Dominant 1 in the Medical Dictionary? Auditory Neuropathy, Autosomal Dominant 1 explanation free. What is Auditory Neuropathy, Autosomal Dominant 1? Meaning of Auditory Neuropathy, Autosomal Dominant 1 medical term. What does Auditory Neuropathy, Autosomal Dominant 1 mean?
Auditory neuropathy is diagnosed when person has normal OAE reading but absent or abnormal Auditory Br ainstem Response. Therefore from OAE and ABR results indicated that hair cell of cochlear is intact but the transmission of auditory nerve to brain is impaired.. Treatment and intervention for auditory neuropathy. There are a few treatment and intervention options for Auditory Neuropathy. However the potential benefit of treatment and intervention are vary to individual.. Frequency modulation (FM) systems. Some professionals reported frequency modulation (FM) systems are helpful for auditory neuropathy with normal hearing. Frequency modulation (FM) system is a device that can transmit sound directly to the listener by sound wave. By using FM system, the listener could concentrate to the speech better and would be useful especially in noisy environment.. ...
INTRODUCTION: the aim of this study was to investigate cochlear functions in patients with hyperemesis gravidarum (HG). METHODES: twenty-nine HG patients (58 ears) and 31 healthy control subjects (62 ears) were included. Audiometry testings at 250 and 500 Hz and 1, 2, 4, 8, 10, 12, 14, 16 kHz were performed to the patients and controls. RESULTS: mean age of patients with HG was 26,5 4,4 years and the mean age of control group was 28,0 4,2 years. At the time of the tests mean gestational age of the HG group and controls were 9 and 11 weeks respectively. No differences were observed between the groups in tympanic membrane status, orother otolaringological evaluations. No significant differences were observed in audiometric tests at any frequencies between the groups (p values for all>0.05). CONCLUSION: there was not a difference between pregnant cases with HG and cases with normal pregnancy in terms of audimetric tests. Cochlear functions are not affectedremarkably in women with HG.
Randomized, double-blind, placebo-controlled safety, pharmacokinetic, pharmacodynamic study of oral SPI-1005 in adults with Menieres disease. All subjects will undergo baseline audiometric testing and have their severity of sensorineural hearing loss, tinnitus and vertigo determined before the start of a 21-day course of treatment with SPI-1005 or placebo. During treatment with SPI-1005, and 7 days and 28 days following the cessation of SPI-1005, subjects will have their hearing loss, tinnitus and vertigo assessed. Additional testing including electrocochleography will be performed at baseline, at the end of SPI-1005 treatment, and 28 days after the SPI-1005 treatment has stopped. Six outpatient visits will be performed over a 7-week period ...
Learn more about Auditory Neuropathy at TriStar Southern Hills DefinitionCausesRisk FactorsSymptomsDiagnosisTreatmentPreventionrevision ...
Learn more about Auditory Neuropathy at Doctors Hospital of Augusta DefinitionCausesRisk FactorsSymptomsDiagnosisTreatmentPreventionrevision ...
Mechanical responses in the basal turn of the guinea-pig cochlea are measured with low-level broad-band noise as the acoustical stimulus [for details see de Boer and Nuttall, J. Acoust. Soc. Am. 101, 3583-3592 (1997)]. Results are interpreted within the framework of a classical three-dimensional model of the cochlea that belongs to a very wide class of nonlinear models. The use of linear-systems analysis for this class of nonlinear models has been justified earlier [de Boer, Audit. Neurosci. 3, 377-388 (1997)]. The data are subjected to inverse analysis with the aim to recover the effective basilar-membrane impedance. This is a parameter function that, when inserted into the model, produces a model response, the resynthesized response, that is similar to the measured response. With present-day solution methods, resynthesis leads back to an almost perfect replica of the original response in the spatial domain. It is demonstrated in this paper that this also applies to the response in the frequency
(article taken from Chinchilla, A Cellulose-Splitter Rodent Wendell Bird In the chinchillas native habitat, in which it has lived for many thousands of years, this animal has existed with a minimum of rainfall and other sources of water and has been able to thrive on relatively low protein fibers, dried grasses in a realtively…
The descriptors used to locate the studies were Cochlear Microphonic and Cochlear Microphonic Potential and the free terms used ... Auditory Dyssynchrony/Cochlear Microphonic Potential/Auditory Neuropathy/Auditory Dyssynchrony/Cochlear Microphonic Potential ... The descriptors used were: Cochlear Microphonic/Auditory Neuropathy/Auditory Dyssynchrony/Cochlear Microphonic AND Auditory ... The study of the Cochlear Microphonic Potential appears to be the most important tool for an accurate diagnosis of this ...
D) Cochlear microphonic potential tuning curves at 64 dB SPL at the times corresponding to the images in A-C. Note the decrease ... CM, cochlear microphonic potential. (E-G) EGTA in the scala media had no effect on stereocilia morphology, except for a small ... I) Peak amplitude of the cochlear microphonic potential in the experiment shown in H. The vertical line at time 0 indicates the ... 4A, EGTA decreased the amplitude of the cochlear microphonic potential (compare center and top waveforms in Fig. 4A; the ...
Action Potentials. Animals. Cerebrospinal Fluid / physiology. Cochlea / physiology*. Cochlear Microphonic Potentials. Guinea ... This amount of TMPA had virtually no toxic effect on cochlear function. The spread of tracer by longitudinal volume flow and ... These findings support the concept that perilymph composition is maintained by local, cochlear mechanisms which do not involve ... probably as a result of cerebrospinal fluid entry through the cochlear aqueduct. When the cochlea was sealed (with recording ...
Cochlear Microphonic Potentials. Hair Cells, Auditory / physiopathology*. Hair Cells, Auditory, Inner / physiopathology. ... Previous Document: Single-neuron labeling and chronic cochlear pathology. III. Stereocilia damage and alterations of th.... ... Single-neuron labeling and chronic cochlear pathology. IV. Stereocilia damage and alterations in rate- and phase-level ...
auditory brainstem response central gain cochlear microphonic compound action potential This is a preview of subscription ... Acute KA effects on cochlear function were assessed using AN compound action potentials (CAPs) and hair cell cochlear ... Bledsoe SC, Bobbin RP, Chihal DM (1981) Kainic acid: an evaluation of its action on cochlear potentials. Hear Res 4:109-120 ... Gu JW, Herrmann BS, Levine RA, Melcher JR (2012) Brainstem auditory evoked potentials suggest a role for the ventral cochlear ...
Electrical potentials. Many of the mechanical events just described have an electrical counter part. The cochlear micro-phonic, ... Waltzman, S.; Cohen, N.; and Shapiro, B. "The Benefits of Cochlear Implantation in the Geriatric Population." Otolaryngology- ... These individuals are potential candidates for a cochlear implant, a surgically implanted device that delivers speech signals ... an electrical potential derived from the cochlea, reflects the displacement of the basilar membrane. The endocochlear potential ...
1982). Cochlear microphonic potentials elicited by biosonar signals in flying bats, Pteronotus p. parnellii. Hearing Res. 7, ... Termed the summating potential and cochlear microphonic, respectively, they arise from direct and alternating transduction ... 1986). Phase-locking in the cochlear nerve of the guinea-pig and its relation to the receptor potential of inner hair cells. ... A) Averaged field potentials recorded in response to 500 and 540 Hz tones presented separately at 90 dB in one male (blue). ...
The cochlear potentials include the cochlear microphonic (CM)…. Read More. 2019-01-16. ... has been employed to assess stimulus-related cochlear potentials and the compound action potential (AP) of the auditory nerve. ... Can Cortical Auditory Evoked Potentials Demonstrate An Electrophysiological Release From Masking In Noise?. February 6, 2019. ... This Pathways article will focus on an auditory evoked potential (AEP) that should be considered more than it has been - ...
Responses from the hair cells are the cochlear microphonic (CM) and summating potential (SP). Responses from the auditory nerve ... In the ongoing response to tones, the ECoG contains both the cochlear microphonic (CM) and auditory nerve neurophonic (ANN) ... Each electrode was analyzed quantitatively using impedance and sound-induced cochlear microphonic (CM) recordings in gerbil ... A cochlear implant is a medical device which directly stimulates cochlear neurons in response to auditory stimuli, assisting in ...
However, when prestin activity was altered with the chloride ionophore tributyltin, both the cochlear microphonic potential and ... Surprisingly, following application of salicylate, outer hair cell stereocilia deflections increased, while cochlear ... indicating that the observed effects did not depend on the endocochlear potential. These data suggest that salicylate may alter ... time-resolved confocal imaging to visualize outer hair cell stereocilia during sound stimulation in the apical turn of cochlear ...
Effects of perilymphatically perfused gentamicin on microphonic potential, lipid labeling and morphology of cochlear tissues. ... Tachibana M, Nishimura H (1986) Incorporation of inositol in the cochlear tissues as revealed by autoradiography. Hearing Res ( ...
Together, the cochlear microphonic, the summating potential, and the compound action potential constitute the potentials ... The synchronously firing action potentials of multiple cochlear nerve afferent fibers can be recorded as the cochlear compound ... The cochlear microphonic is an AC response that follows the acoustic stimulating waveform. It is primarily generated by the ... encoded search term (Cochlear Function) and Cochlear Function What to Read Next on Medscape. Related Conditions and Diseases. * ...
Electrically evoked compound action potentials (ECAPs) reflect the response of the auditory nerve to electrical stimulation ... Electrically evoked compound action potentials (ECAPs) reflect the response of the auditory nerve to electrical stimulation ... The Hybrid cochlear implant (CI) has been developed for individuals with high frequency hearing loss who retain good low ... The Hybrid cochlear implant (CI) has been developed for individuals with high frequency hearing loss who retain good low ...
The cochlear microphonic potential (CM) from the basal cochlea was monitored by a round-window electrode. In 13 of the 20 ... The cochlear microphonic potential (CM) from the basal cochlea was monitored by a round-window electrode. In 13 of the 20 ... The Crista Fenestra and Its Impact on the Surgical Approach to the Scala Tympani during Cochlear Implantation. Conclusion: The ... Histopathology of the Human Inner Ear in the Cogan Syndrome with Cochlear Implantation. The Cogan syndrome is a rare disorder ...
This is in agreement with the measurements of the cochlear microphonic (CM), an extracellular potential arising from sound ... 2005). (c) The time course of the IHC receptor potential (the node 2, , in figure 1b) along the cochlear axis in response to a ... 1973 A quantitative study of cochlear potentials along the scala media of the guinea pig. J. Acoust. Soc. Am. 54, 600-609. doi: ... 1986 Phase-locking in the cochlear nerve of the guinea-pig and its relation to the receptor potential of inner hair-cells. Hear ...
Surprisingly, otoacoustic emissions and cochlear microphonic potentials, which reflect cochlear outer hair cell (OHC) function ... were largely unaffected in mutant mice, whereas auditory brainstem responses and the compound action potential were grossly ...
... namely the cochlear microphonic (CM). At 10 Hz (90 dB SPL), CM amplitudes exceed that of the IHC intracellular potentials as a ... However, various cochlear microphonic, distortion product otoacoustic emission, and fMRI studies have demonstrated the ... high levels of infrasound can alter cochlear function and activate the auditory cortex. Potential long term changes in brain ... In another words, the gain of the cochlear system can be affected by high level infrasound. Moreover, the modulations seen in f ...
Fingerprint Dive into the research topics where School of Communication is active. These topic labels come from the works of this organizations members. Together they form a unique fingerprint. ...
Production of cochlear potentials by inner and outer hair cells. Dallos, P. & Cheatham, M. A., Jan 1 1976, In : journal of the ... Re-examination of avian cochlear potentials. Pierson, M. & Dallos, P., Dec 1 1976, In : Nature. 262, 5569, p. 599-601 3 p.. ...
The compound action potential of the auditory nerve (CAP: Ni-Pi), Ni latency, cochlear microphonic (CM) and summating potential ... The cochlear nerve was exposed using a posterior fossa approach. Extracellular action potentials from single auditory nerve ... Cochlear excitotoxicity plays a role in ischemic- or noise-induced sudden deafness, as well as in tinnitus (Pujol et al. (1999 ... The potentials were amplified (Tektronic TM 503, gain 1000) averaged (256 samples) and stored on a Pentium PC computer. The ...
... such as the cochlear microphonic potential and the compound action potential of the auditory nerve. However, some years ago, it ... Analysis of electrically evoked compound action potential of the auditory nerve in children with bilateral cochlear implants / ... it has been known that placing an electrode near the round window niche allows the recording of cochlear potentials in response ... The cochlear implant device has the capacity to measure the electrically evoked compound action potential of the auditory nerve ...
... summating potential, which is a shoulder on wave 1. In some instances, the cochlear microphonic is inspected. To see the ... Signal is also a problem in Menieres due to reduced size of the cochlear potential, from cochlear damage due to the disease ... 1984). Auditory evoked potentials--the cochlear summating potential in detection of endolymphatic hydrops. Am J Otol 5(6): ... The cochlear microphonic of ECOG may be normal in auditory neuropathy (Santarelli and Arslan 2002) as well as other disorders ...
In all the experimental conditions, no effect was observed on the cochlear microphonic potential. This observation is ... A further slight N-methyl-D-aspartate-induced decrease of the amplitude of the compound action potential, although non ... a significant reduction of the amplitude of the compound action potential and an increase of the N1 latency, both predominant ...
Tasaki, I. and Fernandez, C. Effect of direct current upon the cochlear microphonic and action potential of the guinea pig. ... Tasaki, I., Davis, H., and Legouix, J.P. The space-time patterns of the cochlear microphonic in guinea pig. In 43rd Meeting of ... Tasaki, I., Davis, H., and Eldridge, D.H. Exploration of cochlear potentials in guinea pig with a microelectrode. J Acous Soc ... Fernández, C., Butler, R., Konishi, T., Honrubia, V, and Tasaki, I. Cochlear potentials in the Rhesus and squirrel monkey. J. ...
... a positive correlation of otoacoustic emission was found as well as evidence of cochlear microphonic potentials, which are ... 1. Butinar D, Starr A, Vatovec J. Brainstem auditory evoked potentials and cochlear microphonics in the HMSN family with ... Brainstem auditory evoked potentials did not contain neural component (2).. Eight to ten million Gypsies who live in Europe ... Hearing loss of our patients was caused by an auditory nerve dysfunction in the presence of preserved cochlear outer hear cell ...
We show that cochlear microphonic (CM) amplitude and summating potential (SP) amplitude and latency are normal, consistently ... In some children, however, the ECochG response only consists of the SP, with no prolonged potential. Cochlear implants restore ... the SP component is followed by a markedly prolonged low-amplitude negative potential replacing the compound action potential ( ... This potential is identified at intensities as low as 90 dB below the behavioral threshold. In some ears, a synchronized CAP is ...
... cochlear microphonic cm = congenital malformation cm = cortical mastoidectomy cm = curium cm3 = cubic centimeter cma = ... abundant potentials bsapp = brief, small, abundant, polyphasic potentials bsb = bedside bag bsc = bedside commode bsco = ... evoked potential ep = evoked potentials ep = intermittent esophoria epa = eicosapentaenoic acid epa = eicosapentanoic acid epa ... auditory evoked potentials aer = auditory evoked responses af = acid fast af = afebrile af = amaurosis fugax af = amniotic ...
Cochlear Microphonic Potentials. *Hair Cells, Auditory/physiology. *Humans. *Models, Biological*. *Pitch Perception ... An active process in cochlear mechanics.. Davis H.. Abstract. A model for cochlear mechanics is proposed to take account of its ... At intensities below about 60 dB an active process, the cochlear amplifier (CA), somehow provides additional energy that ... recruitment of loudness in cochlear hearing impairment, the long latency of normal neural responses near threshold, acoustic ...
Cochlear Microphonic Potentials. *Congenital Abnormalities. *Congenital, Hereditary, and Neonatal Diseases and Abnormalities ... Recognition of speech presented at soft to loud levels by adult cochlear implant recipients of three cochlear implant systems. ... Clinical Outcomes of the Cochlear™ Nucleus(®) 5 Cochlear Implant System and SmartSound™ 2 Signal Processing. (Runge CL, Henion ... Case-control analysis of cochlear implant performance in the elderly case-control analysis of cochlear implant performance in ...
  • Andrew Stuart1 & Alyson Butler Lake2 1Department of Communication Sciences & Disorders, East Carolina University, Greenville, NC 2Blue Ridge Ear, Nose, Throat & Plastic Surgery, Lynchburg, VA Electrocochleography (ECochG) has been employed to assess stimulus-related cochlear potentials and the compound action potential (AP) of the auditory nerve. (
  • Electrocochleography (ECoG) responses from the round window to acoustic stimuli can characterize the condition of hair cells and auditory nerve fibers in patients receiving cochlear implants. (
  • Electrically evoked compound action potentials (ECAPs) reflect the response of the auditory nerve to electrical stimulation while electrocochleography (ECochG) reflects the response of the cochlear hair cells and auditory nerve to acoustic stimulation. (
  • Transtympanic electrocochleography (ECochG) has recently been proposed for defining the details of potentials arising in both the cochlea and auditory nerve in this disorder, and with a view to shedding light on the pathophysiological mechanisms underlying auditory dysfunction. (
  • Sensorineural hearing loss was confirmed on electrocochleography and brainstem evoked potentials. (
  • Electrocochleography is a procedure to record the potentials generated by the cochlea and the auditory nerve. (
  • Electrophysiologic techniques such as electrocochleography (ECochG) and electrically-evoked compound action potentials (eCAP) are being studied to localize pathology and estimate residual cochlear vs. neural health. (
  • The Summating Potential Is a Reliable Marker of Electrode Position in Electrocochleography: Cochlear Implant as a Theragnostic Probe. (
  • This study examines the relationships between intraoperative recordings (electrode insertion force and electrocochleography), trauma, and hearing loss after cochlear implantation. (
  • Intracochlear electrocochleography (ECochG) is a potential tool for the assessment of residual hearing in cochlear implant users during implantation and acoustical tuning postoperatively. (
  • Intracochlear electrocochleography (ECOG) offers an objective and a time-efficient method to measure frequency-specific cochlear microphonic or difference thresholds (CM/DIF) thresholds that closely approximate auditory thresholds in adult cochlear implant patients. (
  • Auditory Neuropathy/Dyssynchrony is a disorder characterized by the presence of Otoacoustic Emissions and Cochlear Microphonic Potentials, an absence or severe alteration of Brainstem Evoked Auditory Potential, auditory thresholds incompatible with speech thresholds and altered acoustic reflexes. (
  • Surprisingly, otoacoustic emissions and cochlear microphonic potentials, which reflect cochlear outer hair cell (OHC) function, were largely unaffected in mutant mice, whereas auditory brainstem responses and the compound action potential were grossly abnormal. (
  • The sensitivity to sound of vestibular end organs is also used to produce vestibular evoked myogenic potentials (VEMP), a test that evaluates vestibular function. (
  • Approximately 25 years ago, researchers started to take advantage of the acoustic sensitivity of vestibular receptors to produce vestibular evoked myogenic potentials (VEMP), a short-latency vestibular response recorded from neck muscles in response to intense sound or vibration. (
  • Cervical vestibular-evoked myogenic potentials (cVEMPs) were used to rate the saccular function and lower vestibular nerve. (
  • Abstract Introduction Cervical vestibular-evoked myogenic potentials (cVEMPs) are biphasic, short latency potentials, which represent the inhibition of the contraction of the sternocleidomastoid muscle (SCM) mediated by the saccule, the inferior vestibular nerve, the vestibular nuclei and the medial vestibular spinal tract. (
  • Acute KA effects on cochlear function were assessed using AN compound action potentials (CAPs) and hair cell cochlear microphonics (CMs). (
  • Demonstration of traveling waves in the guinea pig cochlea by recording cochlear microphonics. (
  • The basal turn of cochlea play an important role in generation of cochlear microphonics. (
  • Responses from the hair cells are the cochlear microphonic (CM) and summating potential (SP). (
  • 5] Auditory cortical responses and cochlear modulations due to infrasound exposure have also been observed, despite the subjects' lack of tonal perception. (
  • The CA model explains the detection of small differences in time as well as in frequency, the dual character of the electrocochleogram, recruitment of loudness in cochlear hearing impairment, the long latency of normal neural responses near threshold, acoustic emissions (both stimulated and spontaneous) and the locus of TTS in the frequency range above the exposure tone. (
  • To describe a group of children exhibiting electrophysiologic responses characteristic of auditory neuropathy (AN) who were subsequently identified as having absent or small cochlear nerves (i.e., cochlear nerve deficiency). (
  • 69%) had evidence of a cochlear microphonic (CM) and absent neural responses in at least one ear. (
  • and compound action potential of the eighth nerve) auditory responses were used to assess changes in auditory function resulting from elevated intracranial pressure. (
  • ii) Far-field auditory responses may include an O 2 -dependent cochlear microphonic. (
  • If the auditory system behaved as a simple linear system, neural responses recorded at higher auditory centers should be reduced by half, unless the brain possessed a neural amplification system that can boost these weak cochlear signals. (
  • Short-latency auditory responses were obtained by cross-correlation of continuous, pseudorandom noise stimuli with averaged scalp potentials from adults with normal hearing. (
  • Auditory neuropathy was diagnosed based on abnormal auditory evoked potentials with neural components suggesting severe to profound hearing loss in the presence of cochlear microphonic responses and behavioral reactions to sound at mild to moderate hearing levels. (
  • Similar to those genes directly involved in hair-cell mechanotransduction ( cdh23/sputnik , pcdh15a/orbiter ), the mercury phenotype is characterized by (i) balance defects, (ii) an absence of the acoustic startle reflex, (iii) failure to inflate the swim bladder, (iv) lack of hair-cell-dependent calcium responses in the hindbrain, and (v) undetectable microphonic currents. (
  • This innovative technology applies sophisticated noise filtering algorithms which dramatically reduce artifacts from muscular and ocular electrophysiological activity, as well as electromagnetic interference, in evoked potential responses. (
  • ECoG potentials in response to tone bursts of varying frequency and intensity were recorded from the round window intraoperatively in pediatric and adult patients undergoing cochlear implantation. (
  • Cochlear implantation for patients with severe hearing loss should be considered once the diagnosis is confirmed, as it is possible to achieve a successful level of hearing. (
  • Although children with cochlear nerve deficiency who have a small nerve may benefit from cochlear implantation or amplification, these interventions are obviously contraindicated in children with completely absent cochlear nerves. (
  • For the increasing number of cochlear implantations in subjects with residual hearing, hearing preservation, and thus the prevention of implantation trauma, is crucial. (
  • OBJECTIVE: Determine if changes in middle ear absorbance measured with wide-band tympanometry (WBT) occur following hearing-preservation cochlear implantation (CI). (
  • However, various cochlear microphonic, distortion product otoacoustic emission, and fMRI studies have demonstrated the detection of infrasound by the human inner ear and auditory cortex. (
  • Only one ear with cochlear nerve deficiency had present otoacoustic emissions as measured by distortion-product otoacoustic emissions. (
  • In some children, however, the ECochG response only consists of the SP, with no prolonged potential. (
  • It is, however, unclear how these ECochG recordings from different locations in the cochlea depend on the stimulus parameters, cochlear morphology, implant design, or hair cell degeneration. (
  • The outcomes were compared to actual ECochG recordings from subjects with a cochlear implant (CI). (
  • Capsaicin or the more potent VR agonist, resiniferatoxin (RTX), was infused into the scala tympani of guinea pig cochlea, and their effects on cochlear sensitivity were investigated. (
  • OBJECTIVES: In adult cochlear implant patients, conventional audiometry is used to measure postoperative residual hearing which requires active listening and patient feedback. (
  • ABR is also referred to as auditory evoked response (AER) auditory evoked potential (AEP), brainstem evoked auditory potential (EAP), brainstem auditory evoked potential (BAEP), brainstem auditory evoked response (BAER), and evoked response audiometry. (
  • Capsaicin (20 μM) elevated the threshold of auditory nerve compound action potential and reduced the magnitude of cochlear microphonic and electrically evoked otoacoustic emissions. (
  • Our results show that, when N-methyl-D-aspartate and the antagonist 2-amino-5-phosphonovalerate are perfused through the perilymphatic scalae, they induced, by different mechanisms, a significant reduction of the amplitude of the compound action potential and an increase of the N1 latency, both predominant at high intensity tone burst stimulations. (
  • We show that cochlear microphonic (CM) amplitude and summating potential (SP) amplitude and latency are normal, consistently with a preserved outer and inner hair cell function. (
  • Brainstem auditory evoked potentials (BAER) testing using loud stimuli show a vertex-negative potential with a latency of 3 ms in some human patients with profound deafness of cochlear origin. (
  • This deflection has been termed N3 potential or acoustically evoked short latency negative response (ASNR). (
  • The most useful features of action potential curve are its magnitude and latency. (
  • Compound action potential latencies in dexamethasone-pretreated ears resulted in shorter latency delay than in control ears. (
  • The amplitude of the Cochlear Microphonic in Auditory Neuropathy/Dyssynchrony shows no significant difference from that of normal individuals. (
  • Changes in the resting open probability alter the amplitude of the "silent current" ( 4 , 5 ) that continuously flows into the sensory cells, causing them to operate at a relatively depolarized membrane potential near −40 mV ( 6 ). (
  • However, when prestin activity was altered with the chloride ionophore tributyltin, both the cochlear microphonic potential and the stereocilia deflection amplitude decreased. (
  • A further slight N-methyl-D-aspartate-induced decrease of the amplitude of the compound action potential, although non significant, was observed when the Mg2(+)-free perilymph contained 100 or 1000 microM glycine. (
  • In the majority of OTOF children, the SP component is followed by a markedly prolonged low-amplitude negative potential replacing the compound action potential (CAP) recorded in normally-hearing children. (
  • Stimulation at high rates reduces the amplitude and duration of the prolonged potentials, consistently with their neural generation. (
  • However, the amplitude of the summating potential generated by the IHC and the amplitude of the compound action potential generated by ANF are reduced in proportion to the amount of IHC loss. (
  • Compound action potential (CAP) thresholds and waveforms were monitored at multiple frequencies and the amplitude of the spectrum of the neural noise (SNN) in silence was measured as an indicator of spontaneous neural activity. (
  • Vanadate did not change the resting membrane potential of the smooth muscle cells of the vein, but it increased the rate of rise and the amplitude of the action potentials and the number of action potentials per burst. (
  • Simulations showed that increasing stimulus frequency resulted in a basal shift of the peak cochlear microphonic (CM) amplitude. (
  • The degree of neural survival is expected to be an important factor contributing to variability in speech performance with cochlear implants. (
  • Since cochlear implants (CIs) were first introduced into clinical practice in the mid-1980s, CI technology has changed significantly. (
  • Cochlear implants restore hearing sensitivity, speech perception and neural CAP by electrically stimulating the auditory nerve fibers. (
  • Auditory evoked potentials (AEP) are highly demanded during the whole process of equipping patients with cochlear implants (CI). (
  • Half of the electrical potential driving K + from the scala media into the sensory hair cells arises from the endocochlear potential (EP) (+80 mV) generated in this compartment. (
  • It is theorized that the scala media (cochlear duct), being filled with endolymph, distends and bulges into the 'scala vestibuli' and 'scala tympani', which are in the orange-pink above, on top and bottom respectively. (
  • ECoG recordings in cochlear implant patients can provide important predictive information regarding speech perception outcomes. (
  • Improved Speech Perception in Cochlear Implant Users With Interleaved High-Rate Pulse Trains. (
  • A negative potential is occasionally recorded in humans and animals with profound deafness during brainstem auditory evoked potential (BAER) tests if loud intensities are used. (
  • The presence of the ASNR in dogs and cats with congenital profound deafness associated with white pigmentation is in contrast with a saccular origin of these potentials because these animals often have cochleosaccular degeneration [ 7 , 8 , 9 ]. (
  • It helps in differentiating cochlear from nerve deafness. (
  • This study aims to address the question as to whether VRs exist in the organ of Corti and play a role in cochlear physiology. (
  • Excitotoxic AN damage was induced through bilateral cochlear infusions of kainic acid (KA). (
  • Objective To evaluate the response of cVEMPs in individuals with profound prelingual bilateral cochlear hearing loss. (
  • DESIGN: Thirteen (11 unilateral and 2 bilateral) pediatric cochlear implant patients (mean age = 9.2 years ± 5.1) participated in this study. (
  • Surprisingly, the remaining acoustically responsive ANF behave normally (with low thresholds and sharp tuning) despite massive cochlear damage. (
  • The correlation between CM/DIF and behavioral thresholds has not been established in pediatric cochlear implant patients. (
  • In the present study, CM/DIF thresholds were compared with audiometric thresholds in pediatric cochlear implant patients with postoperative residual hearing. (
  • The ECOG waveforms were analyzed to determine CM/DIF thresholds that were compared with pediatric cochlear implant patients' audiometric thresholds. (
  • CONCLUSIONS: Intracochlear ECOG can be used to measure CM/DIF thresholds in pediatric cochlear implant patients with residual hearing in the implanted ear. (
  • The CM/DIF thresholds are similar to the audiometric thresholds at lower test frequencies and offer an objective method to monitor residual hearing in difficult-to-test pediatric cochlear implant patients. (
  • Bledsoe SC, Bobbin RP, Chihal DM (1981) Kainic acid: an evaluation of its action on cochlear potentials. (
  • Interactions with noise on cochlear potentials, namely compound action potential (CAP) and cochlear microphonic (CM) were studied. (
  • Invention of the double-cannulation method of internal perfusion of the squid giant axon and analyses of the bi-ionic action potential. (
  • The compound action potential (CAP) and cochlear microphonic (CM) potential were recorded to monitor the physiologic status of the afferent neurons and hair cells, respectively. (
  • Supernormal amplitudes of the action potential also occurred during recovery periods. (
  • Compound action potential and cochlear microphonic recordings made from the round window in the current study confirm a preferential high frequency effect of TMT and demonstrate a significant cochlear component to the ototoxic effects of this agent. (
  • An electrocochleographic evaluation revealed cochlear microphonic but absent or markedly abnormal whole nerve action potentials. (
  • The results indicate that the main action of capsaicin is on outer hair cells and suggest that VRs in the cochlea play a role in cochlear homeostasis. (
  • They are compound action potential of auditory nerve (AP), Summating potential (SP), and cochlear potential (CP) also known as cochlear microphonic. (
  • Action potentials are dominated by contributions from high frequency nerve fibers as a response to transient stimuli of rapid onset. (
  • The presence of action potential is dependent on the proper functioning of acoustic nerve fibers. (
  • Therefore, the summating potential and compound action potential (analogous to ABR wave I) can be used to assess the functional status of IHC and ANF in clinical cases of suspected hidden hearing loss. (
  • When 50 percent of the IHC/ANF were destroyed, the compound action potential from the cochlea was reduced by 50 percent. (
  • Fifty minutes after IAA decompression, in dexamethasone-pretreated ears, cochlear microphonic and compound action potential amplitudes at all test frequencies were 10 to 15% less reduced than those in control ears. (
  • maximal diastolic potential the most negative level attained during the cardiac cycle by the cell membrane of a fiber that does not have a constant resting potential, occurring at the end of phase 3 of the action potential. (
  • action potential (AP) the electrical activity developed in a muscle or nerve cell during activity. (
  • The objective was to design in gerbils a model of reversible decrease in cochlear blood flow (CBF) and analyze its influence on cochlear function. (
  • HYPOTHESIS: Local application of dexamethasone to the round window (RW) niche prevents cochlear damage caused by local reversible ischemia. (
  • We used two- and three-dimensional time-resolved confocal imaging to visualize outer hair cell stereocilia during sound stimulation in the apical turn of cochlear explant preparations from the guinea pig. (
  • Surprisingly, following application of salicylate, outer hair cell stereocilia deflections increased, while cochlear microphonic potentials decreased. (
  • It is unclear whether cochlear amplification arises uniquely from a voltage-dependent mechanism (electromotility) associated with outer hair cells (OHCs) or whether other mechanisms are necessary, for the voltage response of OHCs is apparently attenuated excessively by the membrane electrical filter. (
  • This tiny difference produces asymmetrical electrical potentials from the outer hair cells, which add up over time, and shifts the baseline of wave 1. (
  • The electrocochleographic and otoacoustic emission data suggest that the outer hair cells are functioning normally and that the loss is not cochlear in origin. (
  • Outer hair cells of cochlea are responsible for this potential. (
  • To determine the functional significance of the sodium-transport mechanisms of the outer hair cells (OHCs) in vivo, the effect of reduced perilymphatic sodium on cochlear potentials was investigated in the guinea pig by perfusion of scala tympani with a modified artificial perilymph. (
  • When patients cannot be assessed with behavioral techniques, auditory evoked potentials are often employed. (
  • This potential is identified at intensities as low as 90 dB below the behavioral threshold. (
  • In children with appropriate available behavioral testing results, all ears without cochlear nerves were identified as having a profound hearing loss. (
  • While this frequency dependence suggests a cochlear locus of injury, both the known neurotoxic effects of TMT and the time course of the behavioral impairment suggest a more central locus of injury. (
  • Using a novel electrophysiological approach, we recorded both brainstem and cortical speech-evoked brain event-related potentials (ERPs) in older, hearing-matched human listeners who did and did not present with subtle cognitive impairment revealed through behavioral neuropsychological testing. (
  • In the ongoing response to tones, the ECoG contains both the cochlear microphonic (CM) and auditory nerve neurophonic (ANN) which are a challenge to separate. (
  • The cochlear microphonic of ECOG may be normal in auditory neuropathy (Santarelli and Arslan 2002) as well as other disorders in which the cochlea is preserved but the auditory nerve is damaged (Yokoyama, Nishida et al. (
  • The conventional explanation for the summating potential (SP) of ECOG is that there is a nonlinear response caused by elevated endolymphatic pressure and distension. (
  • When these recordings are made from electrodes placed close to the source of impulse the recorded potentials are quite large. (
  • If the recording is made from electrodes placed in far field, the potentials recorded are small in nature. (
  • To test this hypothesis, electrodes were chronically implanted at the level of the cochlea, inferior colliculus, and auditory cortex to record the local field potentials from these regions pre- and post-carboplatin. (
  • BACKGROUND: Cochlear ischemia induced by internal auditory artery (IAA) compression/ stretching is thought to cause postoperative sensory hearing loss after attempted hearing preservation removal of acoustic neuroma tumors. (
  • Dexamethasone showed a protective effect on cochlear function after local ischemia. (
  • Monitoring device use in cochlear implant recipients of all ages provides important information about the listening conditions encountered in recipients' daily lives that may support counseling and assist in the further management of their device settings. (
  • DESIGN: WBT absorbance was measured bilaterally during pre- and postoperative clinical office visits in five unilaterally-implanted cochlear implant recipients. (
  • Purpose The aim of this study was to quantify the portion of variance in several measures suggested to be indicative of peripheral noise-induced cochlear synaptopathy and hidden hearing disorder that can be attributed to individual cognitive capacity. (
  • To better understand the nature of KA-induced excitotoxic damage to the cochlear afferent neurons, KA, at two different concentrations (0.3 or 5 mM), was injected directly into the inner ear of adult chickens. (
  • Tachibana M, Anniko M, Schacht J (1983) Effects of perilymphatically perfused gentamicin on microphonic potential, lipid labeling and morphology of cochlear tissues. (
  • The protocol for the determination of Cochlear Microphonic must include the use of insert earphones, reverse polarity and blocking the stimulus tube to eliminate electrical artifact interference. (
  • The alternating polarity causes the cochlear potential to cancel. (
  • Understanding these waveforms along with distortions seen in the recordings could help us evaluate cochlear health and neural survival. (
  • In extracellular recordings from hair cells, we observed that D1R agonist SKF-38393 increased microphonic potentials, whereas D1R antagonist SCH-23390 decreased microphonic potentials. (
  • Application of 2 μM RTX resulted in cochlear sensitivity alterations similar to that by capsaicin, which could also be blocked by capsazepine. (
  • Over the last 10 years, the auditory steady-state response (ASSR) has received a great deal of attention from researchers and clinicians as a potential alternative to ABR for estimating hearing sensitivity in infants. (
  • The cochlear microphonic potential (CM) from the basal cochlea was monitored by a round-window electrode. (
  • b )(i) Equivalent electrical circuit of a single hair cell and (ii) a cochlear cross section from ( a ). (
  • However, these results are likely confounded by cochlear hair cell damage. (
  • There are three classes of potentials that can be recorded from the cochlea and auditory nerve in response to a sound stimuli. (
  • The study of the Cochlear Microphonic Potential appears to be the most important tool for an accurate diagnosis of this pathology. (
  • Single-neuron labeling and chronic cochlear pathology. (
  • The direction of this potential is dependent on complex interaction between the stimulus parameters and the location of the recording electrode. (
  • Field potentials from sound-transducing neurons in the antennae contain both sustained and oscillatory components to pure and paired tone stimuli. (
  • The number of cochlear ganglion neurons in the KA-H group decreased progressively from 1 to 8-20 weeks, whereas hair cells in the basilar papilla remained morphologically intact out to 20 weeks after KA. (
  • Capsaicin, the vanilloid that selectively activates vanilloid receptors (VRs) on sensory neurons for noxious perception, has been reported to increase cochlear blood flow (CBF). (
  • 2 msec) attributable to cochlear microphonic, which were prominent in earlier work on guinea pigs, were not well seen in these human data. (
  • The objective is to record wave-1 (there are 5 waves), with greater accuracy and to detect the "summating potential", which is a shoulder on wave 1. (
  • Increase the people with persistent or material that treatment of the late with its back monitoring, and objective success, with potential to the body (suture, mesh) erosion control of a point n. (