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The American Journal of Otology Sep 2000Experimental endolymphatic hydrops leads to an endolymph-perilymph pressure imbalance that is responsible for the loss of auditory sensitivity in the ear.
HYPOTHESIS
Experimental endolymphatic hydrops leads to an endolymph-perilymph pressure imbalance that is responsible for the loss of auditory sensitivity in the ear.
BACKGROUND
This study investigates whether intralabyrinthine pressure is a factor in the auditory dysfunction of experimental endolymphatic hydrops.
METHODS
Auditory function was investigated in 10 guinea pigs 90 to 120 days after endolymphatic sac ablation by measuring compound action potentials in response to acoustic stimuli including alternating clicks and tone bursts of 0.5, 1, 2, 4, and 8 kHz. After auditory thresholds to the various stimuli were established, endolymphatic and perilymphatic pressures were measured with a no-flow micropressure measuring system. The cause of the hearing loss in Meniere's disease, especially in the early phases of this condition, remains an enigma. Histologic temporal bone preparations show a disproportion in the volume of endolymph to perilymph with an expanded and distorted membranous labyrinth. Speculation as to whether an endolymph-perilymph fluid pressure imbalance is responsible for these morphologic changes were raised by Hallpike and Cairns (1) in their initial report of the histopathology of Meniere's disease. Further speculation has questioned whether this pressure imbalance may be responsible for the symptoms and physical finding of this condition, including hearing loss. The ability to produce experimental endolymphatic hydrops in the guinea pig secondary to surgical occlusion of the endolymphatic sac and duct has been useful in studying various aspects of Meniere's disease (2). Investigators have been able to demonstrate auditory threshold shifts with hydrops. Elevated endolymph-perilymph pressure gradients have also been demonstrated (3). This
RESULTS
Increased auditory thresholds were noted in the hydrops ears at all tested parameters (p < 0.03). A relative increase in endolymph over perilymph pressure was found in hydrops ears as previously reported. The increase in endolymph-perilymph pressure of hydrops could not be correlated directly to the elevated auditory threshold shift.
CONCLUSION
Endolymphatic hydrops is a complex pathologic state with multiple inner ear alterations including abnormal intralabyrinthine pressure. Factors other than or in addition to pressure contribute to the auditory threshold shift of hydrops.
Topics: Animals; Auditory Threshold; Disease Models, Animal; Ear, Inner; Endolymphatic Hydrops; Guinea Pigs; Manometry; Pressure
PubMed: 10993453
DOI: No ID Found -
Clinical Neurophysiology : Official... Apr 2008To determine whether central auditory function in preterm infants correlates with peripheral auditory threshold and whether threshold elevation affects central auditory...
OBJECTIVE
To determine whether central auditory function in preterm infants correlates with peripheral auditory threshold and whether threshold elevation affects central auditory function.
METHODS
Brainstem auditory evoked response (BAER) was recorded at term age using maximum length sequence (MLS) with 91-910/s clicks in 133 preterm infants (gestation 28-36 weeks). The relationship between MLS BAER variables and BAER threshold was analyzed.
RESULTS
The latencies and amplitudes of all MLS BAER waves correlated significantly with BAER threshold. However, no correlation was found between MLS BAER interpeak intervals and BAER threshold at any rates. In preterm infants with a threshold >20dB nHL (n=30), MLS BAER wave latencies were all significantly longer than in those with a threshold < or = 20dB nHL (n=103) (P<0.01-0.001). MLS BAER wave amplitudes were significantly smaller than in those 20dB nHL (P<0.05-0.001). However, no interpeak intervals differed significantly between the two groups of infants. V/I amplitude ratio was similar in the two groups. These findings were true of all click rates. Click rate-dependent changes in MLS BAER of the preterm infants with an elevated BAER threshold are generally similar to those with a normal threshold.
CONCLUSIONS
Brainstem auditory function does not closely correlate with peripheral auditory threshold at term in preterm infants. Elevation in peripheral threshold due to middle ear disorders does not significantly affect functional status of the auditory brainstem.
SIGNIFICANCE
Short term peripheral conductive auditory abnormality does not significantly affect the immature central auditory function.
Topics: Auditory Threshold; Evoked Potentials, Auditory, Brain Stem; Female; Humans; Infant, Newborn; Infant, Premature; Male; Pregnancy; Premature Birth
PubMed: 18282800
DOI: 10.1016/j.clinph.2007.12.012 -
Ear and Hearing 2014
Topics: Audiometry, Pure-Tone; Auditory Threshold; Hearing Loss; Humans
PubMed: 24722511
DOI: 10.1097/AUD.0000000000000042 -
Consciousness and Cognition May 2019One theory of visual awareness proposes that electrophysiological activity related to awareness occurs in primary visual areas approximately 200 ms after stimulus...
One theory of visual awareness proposes that electrophysiological activity related to awareness occurs in primary visual areas approximately 200 ms after stimulus onset (visual awareness negativity: VAN) and in fronto-parietal areas about 300 ms after stimulus onset (late positivity: LP). Although similar processes might be involved in auditory awareness, only sparse evidence exists for this idea. In the present study, we recorded electrophysiological activity while subjects listened to tones that were presented at their own awareness threshold. The difference in electrophysiological activity elicited by tones that subjects reported being aware of versus unaware of showed an early negativity about 200 ms and a late positivity about 300 ms after stimulus onset. These results closely match those found in vision and provide convincing evidence for an early negativity (auditory awareness negativity: AAN), as well as an LP. These findings suggest that theories of visual awareness are also applicable to auditory awareness.
Topics: Adult; Auditory Threshold; Awareness; Cerebral Cortex; Electroencephalography; Evoked Potentials; Female; Humans; Male; Young Adult
PubMed: 30928900
DOI: 10.1016/j.concog.2019.03.008 -
Journal of the American Academy of... Oct 2005Psychophysical and P300 (P3) thresholds and suprathreshold measures were obtained in 16 normal-hearing subjects. Subjects followed a classic oddball paradigm using 1000...
Psychophysical and P300 (P3) thresholds and suprathreshold measures were obtained in 16 normal-hearing subjects. Subjects followed a classic oddball paradigm using 1000 (frequent) and 2000 Hz (rare) tones as stimuli. The P3 was obtained for all 16 subjects at or 5 dB above their behavioral threshold. The P3 was obtained more often at behavioral threshold and 5 dB SL than N1 and P2 late potentials. The P3 was larger in amplitude than either the N1 or the P2 at threshold and for 75 dB SPL stimuli. In comparing P3s obtained at threshold and for the 75 dB stimuli, significant effects were noted in latency and amplitude reflecting exogenous aspects to this endogenous potential. Differences in latency and amplitude were also noted in N1 and P2 waveforms obtained from the rare versus frequent stimuli. Clinical implications of these results are discussed.
Topics: Adolescent; Adult; Audiometry, Pure-Tone; Auditory Threshold; Child; Evoked Potentials, Auditory; Female; Humans; Male
PubMed: 16515141
DOI: 10.3766/jaaa.16.9.7 -
Psychopharmacology Sep 2001Auditory threshold (AT) measurement method has become the standard behavioral procedure for describing auditory sensitivity. Therefore, the AT measurement method is...
RATIONALE
Auditory threshold (AT) measurement method has become the standard behavioral procedure for describing auditory sensitivity. Therefore, the AT measurement method is applicable to evaluation of auditory function. However, only a few studies have been performed to clarify the alteration of audibility under the influence of alcohol on normal humans by measurement of AT.
OBJECTIVE
The fact that blood alcohol concentration (BAC) is influenced by the dose of alcohol and the time of measurement suggests that the effects of alcohol may also be altered by the same factors. The present study was conducted to elucidate how alcohol ingestion method affects the AT at a wider range from lower to higher frequency in the time course.
METHODS
Fifteen paid Japanese (seven men and eight women, 20-33 years of age) were employed in AT measurements at an octave frequency ranging from 250 to 8,000 Hz before and 5, 30, 60, 120, 240 and 480 min after drinking various amounts (125, 250, 500 and 1,500 ml) of normal beer (5% alcohol) or alcohol-free beer.
RESULTS
The AT was significantly reduced within 30 min after the ingestion of 250 and 500 ml of beer, occurring on and after peak BAC. The reducing effect disappeared 480 min after ingestion.
CONCLUSIONS
Drinking extra small amounts of alcohol induces the reduction of AT. The effect of alcohol on AT is altered by the alcoholic dose used in testing.
Topics: Adult; Alcohol Drinking; Analysis of Variance; Auditory Threshold; Central Nervous System Depressants; Dose-Response Relationship, Drug; Ethanol; Female; Humans; Male
PubMed: 11594444
DOI: 10.1007/s002130100782 -
The Journal of the Acoustical Society... Sep 2006Krisha [J. Acoust. Soc. Am., in press (2006)] has commented that an explanation based on presynaptic calcium accumulation at the inner hair cell is an incorrect... (Review)
Review
Krisha [J. Acoust. Soc. Am., in press (2006)] has commented that an explanation based on presynaptic calcium accumulation at the inner hair cell is an incorrect explanation for the success of a model of the auditory periphery [Meddis, R., J. Acoustic. Soc. Am. 119, 406-417 (2006)] in explaining data on first-spike auditory nerve latency. This reply accepts the criticism and accepts the strength of an alternative explanation based on expected latencies in random sequences of low-probability events. This reply also goes on briefly to explore the application of this argument to other phenomena, including the dependence of absolute auditory threshold on the duration of the stimulus. This has wide-ranging implications for the concept of "temporal integration" in psychophysics.
Topics: Action Potentials; Auditory Threshold; Cochlear Nerve; Computer Simulation; Humans; Models, Biological; Reaction Time
PubMed: 17004441
DOI: 10.1121/1.2221413 -
Philosophical Transactions of the Royal... Apr 2012A sequence of sounds may be heard as coming from a single source (called fusion or coherence) or from two or more sources (called fission or stream segregation). Each... (Review)
Review
A sequence of sounds may be heard as coming from a single source (called fusion or coherence) or from two or more sources (called fission or stream segregation). Each perceived source is called a 'stream'. When the differences between successive sounds are very large, fission nearly always occurs, whereas when the differences are very small, fusion nearly always occurs. When the differences are intermediate in size, the percept often 'flips' between one stream and multiple streams, a property called 'bistability'. The flips do not generally occur regularly in time. The tendency to hear two streams builds up over time, but can be partially or completely reset by a sudden change in the properties of the sequence or by switches in attention. Stream formation depends partly on the extent to which successive sounds excite different 'channels' in the peripheral auditory system. However, other factors can play a strong role; multiple streams may be heard when successive sounds are presented to the same ear and have essentially identical excitation patterns in the cochlea. Differences between successive sounds in temporal envelope, fundamental frequency, phase spectrum and lateralization can all induce a percept of multiple streams. Regularities in the temporal pattern of elements within a stream can help in stabilizing that stream.
Topics: Acoustic Stimulation; Attention; Auditory Perception; Auditory Threshold; Humans; Sound
PubMed: 22371614
DOI: 10.1098/rstb.2011.0355 -
The Journal of the Acoustical Society... Jan 2006A computer model of the auditory periphery was used to address the question of what constitutes the physiological substrate of absolute auditory threshold. The model was...
A computer model of the auditory periphery was used to address the question of what constitutes the physiological substrate of absolute auditory threshold. The model was first evaluated to show that it is consistent with experimental findings that auditory-nerve fiber spikes can be predicted to occur when the running integral of stimulus pressure reaches some critical value [P. Heil and H. Neubauer, J. Neurosci. 15, 7404-7415 (2001)]. It was then modified to examine two ways in which the accumulation and clearance of receptor presynaptic calcium might explain this effect. Both methods gave results that matched the animal data. It was also shown how the rate of clearance of presynaptic calcium could be used to explain the origin of differences between low and high spontaneous-rate fiber types. When spiking activity is aggregated across a number of similar high spontaneous-rate fibers and used as the input to a model of a cochlear nucleus coincidence neuron, its response can be used to judge whether or not a stimulus is present. A simulated psychophysical experiment then demonstrated that this simple decision procedure can reproduce measurements of absolute auditory threshold for tones in quiet where the threshold is a joint function of both time and level.
Topics: Acoustic Stimulation; Animals; Auditory Threshold; Calcium; Cochlear Nerve; Computer Simulation; Guinea Pigs; Models, Biological; Reaction Time
PubMed: 16454295
DOI: 10.1121/1.2139628 -
Journal of Neurophysiology Jul 2004
Topics: Acoustic Stimulation; Animals; Auditory Cortex; Auditory Threshold; Housing, Animal; Humans; Neurons; Reaction Time
PubMed: 15212436
DOI: 10.1152/jn.00213.2004