Mechanisms of Intraoperative Brainstem Auditory Evoked Potential Changes

Legatt, Alan D.

doi:10.1097/00004691-200210000-00003

Cited by 137 publications

(60 citation statements)

References 46 publications

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“…EABR responses were characterized by the latencies and the amplitudes of peaks III and V. For CI patients, peak III, which is generated by the cochlear nucleus, occurs approximately 2 ms after the onset of the stimulus, whereas peak V, which is generated by the lateral lemniscus-inferior colliculus (e.g., Legatt 2002;Møller et al 1995), occurs approximately 4 ms after the onset of the stimulus. Latency was defined as the time position of the respective peaks.…”

Section: Figmentioning

confidence: 99%

“…Given that peak III is mainly generated by the cochlear nucleus and peak V is generated by the lateral lemniscus-inferior colliculus (e.g., Legatt 2002;Møller et al 1995), it is likely that small time differences at peak III will result more evident at higher levels of the auditory pathway (peak V) as a result of the interaction between linear and nonlinear time integration along the ascending stages.…”

Section: Polarity and Synchronizationmentioning

confidence: 99%

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The Polarity Sensitivity of the Electrically Stimulated Human Auditory Nerve Measured at the Level of the Brainstem

Undurraga

Carlyon

Wouters

et al. 2013

JARO

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Recent behavioral studies have suggested that the human auditory nerve of cochlear implant (CI) users is mainly excited by the positive (anodic) polarity. Those findings were only obtained using asymmetric pseudomonophasic (PS) pulses where the effect of one phase was measured in the presence of a counteracting phase of opposite polarity, longer duration, and lower amplitude than the former phase. It was assumed that only the short high-amplitude phase was responsible for the excitation. Similarly, it has been shown that electrically evoked compound action potentials could only be obtained in response to the anodic phases of asymmetric pulses. Here, experiment 1 measured electrically evoked auditory brainstem responses to standard symmetric, PS, reversed pseudomonophasic, and reversed pseudomonophasic with inter-phase gap (6 ms) pulses presented for both polarities. Responses were time locked to the short high-amplitude phase of asymmetric pulses and were smaller, but still measurable, when that phase was cathodic than when it was anodic. This provides the first evidence that cathodic stimulation can excite the auditory system of human CI listeners and confirms that this stimulation is nevertheless less effective than for the anodic polarity. A second experiment studied the polarity sensitivity at different intensities by means of a loudness balancing task between pseudomonophasic anodic (PSA) and pseudomonophasic cathodic (PSC) stimuli. Previous studies had demonstrated greater sensitivity to anodic stimulation only for stimuli producing loud percepts. The results showed that PSC stimuli required higher amplitudes than PSA stimuli to reach the same loudness and that this held for current levels ranging from 10 to 100 % of the dynamic range.

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Section: Figmentioning

confidence: 99%

Section: Polarity and Synchronizationmentioning

confidence: 99%

The Polarity Sensitivity of the Electrically Stimulated Human Auditory Nerve Measured at the Level of the Brainstem

Undurraga

Carlyon

Wouters

et al. 2013

JARO

View full text Add to dashboard Cite

show abstract

“…Neural conduction, and ABR latency, is also influenced by body temperature (Legatt 2002). An increase in body temperature leads to an increase in neural conduction speed and a reduction in ABR latency (Stockard et al 1978;Markand et al 1987).…”

Section: Mechanisms Mediating Rapid Reduction In Abr Latency Post-udmentioning

confidence: 99%

Rapid Increase in Neural Conduction Time in the Adult Human Auditory Brainstem Following Sudden Unilateral Deafness

Maslin

Lloyd

Rutherford

et al. 2015

JARO

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Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in subcortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre=6.55 ms; mean post=6.15 ms; pG0.001). A latency reduction was also observed for wave III (mean pre=4.40 ms; mean post=4.13 ms; pG0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.

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“…Recruitment and conduction of auditory nerve firing is not affected in Gtf2ird1 knockout mice By analysing the peak amplitudes and latencies of the ABR waveforms, effects on the recruitment and conduction elements of the auditory pathway can be assessed. 26 The peak amplitudes and latencies of P1-N1, P2-N2, P3-N3 and P4-N4 elements of the ABR waveform ( Figure 3a) were analysed at 4 kHz (45 dB), where the greatest threshold difference was observed across the range of frequencies measured. This analysis showed that there were no significant differences in the latencies or growth functions of the first four peaks in the ABR between homozygous Gtf2ird1 −/− and wild-type mice (Figure 4a and b, wild type n ≥ 14; Gtf2ird1 −/− n ≥ 11; P = 0.12 via two-way ANOVA on ranks for 3A; P = 0.41 for peak I, P = 0.48 for peak II, P = 0.15 for peak III and P = 0.08 for peak IV via Holm-Sidak pairwise comparisons for Figure 4b).…”

Section: Structure Of the Gtf2ird1 Knockout Cochleamentioning

confidence: 99%

The role of GTF2IRD1 in the auditory pathology of Williams–Beuren Syndrome

et al. 2014

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Williams-Beuren Syndrome (WBS) is a rare genetic condition caused by a hemizygous deletion involving up to 28 genes within chromosome 7q11.23. Among the spectrum of physical and neurological defects in WBS, it is common to find a distinctive response to sound stimuli that includes extreme adverse reactions to loud, or sudden sounds and a fascination with certain sounds that may manifest as strengths in musical ability. However, hearing tests indicate that sensorineural hearing loss (SNHL) is frequently found in WBS patients. The functional and genetic basis of this unusual auditory phenotype is currently unknown. Here, we investigated the potential involvement of GTF2IRD1, a transcription factor encoded by a gene located within the WBS deletion that has been implicated as a contributor to the WBS assorted neurocognitive profile and craniofacial abnormalities. Using Gtf2ird1 knockout mice, we have analysed the expression of the gene in the inner ear and examined hearing capacity by evaluating the auditory brainstem response (ABR) and the distortion product of otoacoustic emissions (DPOAE). Our results show that Gtf2ird1 is expressed in a number of cell types within the cochlea, and Gtf2ird1 null mice showed higher auditory thresholds (hypoacusis) in both ABR and DPOAE hearing assessments. These data indicate that the principal hearing deficit in the mice can be traced to impairments in the amplification process mediated by the outer hair cells and suggests that similar mechanisms may underpin the SNHL experienced by WBS patients.

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Mechanisms of Intraoperative Brainstem Auditory Evoked Potential Changes

Cited by 137 publications

References 46 publications

The Polarity Sensitivity of the Electrically Stimulated Human Auditory Nerve Measured at the Level of the Brainstem

The Polarity Sensitivity of the Electrically Stimulated Human Auditory Nerve Measured at the Level of the Brainstem

Rapid Increase in Neural Conduction Time in the Adult Human Auditory Brainstem Following Sudden Unilateral Deafness

The role of GTF2IRD1 in the auditory pathology of Williams–Beuren Syndrome

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