scholarly journals Complementary metrics of human auditory nerve function derived from compound action potentials

2017 ◽  
Author(s):  
Kelly C. Harris ◽  
Kenneth I. Vaden ◽  
Carolyn M. McClaskey ◽  
James W. Dias ◽  
Judy R. Dubno
Keyword(s):  
Auditory Processing ◽  
Auditory Nerve ◽  
Noise Exposure ◽  
Basilar Membrane ◽  
Compound Action Potential ◽  
Neural Synchrony ◽  
Younger Adults ◽  
Physiological Properties ◽  
Compound Action Potentials ◽  
Compound Action

AbstractDeclines in auditory nerve (AN) function contribute to suprathreshold auditory processing and communication deficits in individuals with normal hearing, hearing loss, hyperacusis, and tinnitus. Procedures to characterize AN loss or dysfunction in humans are limited. We report several novel complementary metrics to characterize AN function noninvasively in humans using the compound action potential (CAP), a direct measure of summated AN activity. We examined how these metrics change with stimulus intensity, and interpreted these changes within a framework of known physiological properties of the basilar membrane and AN. Our results reveal how neural synchrony and the recruitment of AN fibers with later first-spike latencies likely contribute to the CAP, affect auditory processing, and differ with noise exposure history in younger adults despite normal pure-tone thresholds. Moving forward, these new metrics, when applied to patient populations, can provide a means to characterize cochlear synaptopathy and other deficits in AN function in humans.New and noteworthyLoss or inactivity of auditory nerve (AN) fibers is thought to contribute to suprathreshold auditory processing deficits, but evidence-based methods to assess these effects are not available. We describe several novel metrics that may be used to quantify neural synchrony and characterize AN function.

scholarly journals Complementary metrics of human auditory nerve function derived from compound action potentials

2018 ◽  
Vol 119 (3) ◽  
pp. 1019-1028 ◽  
Author(s):  
Kelly C. Harris ◽  
Kenneth I. Vaden ◽  
Carolyn M. McClaskey ◽  
James W. Dias ◽  
Judy R. Dubno
Keyword(s):  
Auditory Processing ◽  
Auditory Nerve ◽  
Noise Exposure ◽  
Basilar Membrane ◽  
Compound Action Potential ◽  
Neural Synchrony ◽  
Younger Adults ◽  
Physiological Properties ◽  
Compound Action Potentials ◽  
Compound Action

Declines in auditory nerve (AN) function contribute to suprathreshold auditory processing and communication deficits in individuals with normal hearing, hearing loss, hyperacusis, and tinnitus. Procedures to characterize AN loss or dysfunction in humans are limited. We report several novel complementary metrics using the compound action potential (CAP), a direct measure of summated AN activity. Together, these metrics may be used to characterize AN function noninvasively in humans. We examined how these metrics change with stimulus intensity and interpreted these changes within a framework of known physiological properties of the basilar membrane and AN. Our results reveal how neural synchrony and the recruitment of AN fibers with longer first-spike latencies likely contribute to the CAP, affect auditory processing, and differ with noise exposure history in younger adults with normal pure-tone thresholds. Moving forward, this new battery of metrics provides a crucial step toward new diagnostics of AN function in humans. NEW & NOTEWORTHY Loss or inactivity of auditory nerve (AN) fibers is thought to contribute to suprathreshold auditory processing deficits, but evidence-based methods to assess these effects are not available. We describe several novel metrics that together may be used to quantify neural synchrony and characterize AN function in humans.

Neural Generators of Brainstem Evoked Potentials Results from Human Intracranial Recordings

1981 ◽  
Vol 90 (6) ◽  
pp. 591-596 ◽  
Author(s):  
Aage R. Møsller ◽  
Peter J. Jannetta ◽  
Margareta B. Møsller
Keyword(s):  
Evoked Potentials ◽  
Auditory Nerve ◽  
Action Potentials ◽  
Compound Action Potential ◽  
Main Peak ◽  
Negative Wave ◽  
Compound Action Potentials ◽  
Brainstem Evoked Potentials ◽  
Intracranial Recordings ◽  
Compound Action

Recordings were made from the auditory nerve near its entrance into the brainstem during neurosurgical operations for cranial nerve disorders. The recorded compound action potentials in response to 2000 Hz tonebursts at 90 dB were characterized by a negative peak with a latency of 3.0 to 3.7 ms. When these compound action potentials were compared with the brainstem evoked potentials (BSEP) recorded from the scalp during the operation or before the operation, it was found that the latency of the main peak of the compound action potential matched the latency of the vertex negative wave located between waves II and III (P2) and the potentials recorded from the nerve were found to match the N2P2N3 complex of the scalp-recorded BSEP. The results indicate that the auditory nerve is the neural generator of the two first peaks in the human BSEP, in contrast to the results of experiments in animals which show that the second peak originates in the cochlear nucleus.

scholarly journals Comparison of Electrically Evoked Compound Action Potential Thresholds and Loudness Estimates for the Stimuli Used to Program the Advanced Bionics Cochlear Implant

2010 ◽  
Vol 21 (01) ◽  
pp. 016-027 ◽  
Author(s):  
Eun Kyung Jeon ◽  
Carolyn J. Brown ◽  
Christine P. Etler ◽  
Sara O'Brien ◽  
Li-Kuei Chiou ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Dynamic Range ◽  
Compound Action Potential ◽  
Behavioral Measures ◽  
Speech Processor ◽  
Compound Action Potentials ◽  
Evoked Compound Action Potential ◽  
The Individual ◽  
The Relationship ◽  
Compound Action

Background: In the mid-1990s, Cochlear Corporation introduced a cochlear implant (CI) to the market that was equipped with hardware that made it possible to record electrically evoked compound action potentials (ECAPs) from CI users of all ages. Over the course of the next decade, many studies were published that compared ECAP thresholds with levels used to program the speech processor of the Nucleus CI. In 2001 Advanced Bionics Corporation introduced the Clarion CII cochlear implant (the Clarion CII internal device is also known as the CII Bionic Ear). This cochlear implant was also equipped with a system that allowed measurement of the ECAP. While a great deal is known about how ECAP thresholds compare with the levels used to program the speech processor of the Nucleus CI, relatively few studies have reported comparisons between ECAP thresholds and the levels used to program the speech processor of the Advanced Bionics CI. Purpose: To explore the relationship between ECAP thresholds and behavioral measures of perceptual dynamic range for the range of stimuli commonly used to program the speech processor of the Advanced Bionics CI. Research Design: This prospective and experimental study uses correlational and descriptive statistics to define the relationship between ECAP thresholds and perceptual dynamic range measures. Study Sample: Twelve postlingually deafened adults participated in this study. All were experienced users of the Advanced Bionics CI system. Data Collection and Analysis: ECAP thresholds were recorded using the commercially available SoundWave software. Perceptual measures of threshold (T-level), most comfortable level (M-level), and maximum comfortable level (C-level) were obtained using both “tone bursts” and “speech bursts.” The relationship between these perceptual and electrophysiological variables was defined using paired t-tests as well as correlation and linear regression. Results: ECAP thresholds were significantly correlated with the perceptual dynamic range measures studied; however, correlations were not strong. Analysis of the individual data revealed considerable discrepancy between the contour of ECAP threshold versus electrode function and the behavioral loudness estimates used for programming. Conclusion: ECAP thresholds recorded from Advanced Bionics cochlear implant users always indicated levels where the programming stimulus was audible for the listener. However, the correlation between ECAP thresholds and M-levels (the primary metric used to program the speech processor of the Advanced Bionics CI), while statistically significant, was quite modest. If programming levels are to be determined on the basis of ECAP thresholds, care should be taken to ensure that stimulation is not uncomfortably loud, particularly on the basal electrodes in the array.

Contribution of auditory nerve fibers to compound action potential of the auditory nerve

2014 ◽  
Vol 112 (5) ◽  
pp. 1025-1039 ◽  
Author(s):  
Jérôme Bourien ◽  
Yong Tang ◽  
Charlène Batrel ◽  
Antoine Huet ◽  
Marc Lenoir ◽  
...  
Keyword(s):  
Action Potential ◽  
Auditory Nerve ◽  
Computational Simulation ◽  
Round Window ◽  
Hearing Threshold ◽  
Compound Action Potential ◽  
Nerve Fibers ◽  
Auditory Nerve Fibers ◽  
Round Window Niche ◽  
Compound Action

Sound-evoked compound action potential (CAP), which captures the synchronous activation of the auditory nerve fibers (ANFs), is commonly used to probe deafness in experimental and clinical settings. All ANFs are believed to contribute to CAP threshold and amplitude: low sound pressure levels activate the high-spontaneous rate (SR) fibers, and increasing levels gradually recruit medium- and then low-SR fibers. In this study, we quantitatively analyze the contribution of the ANFs to CAP 6 days after 30-min infusion of ouabain into the round window niche. Anatomic examination showed a progressive ablation of ANFs following increasing concentration of ouabain. CAP amplitude and threshold plotted against loss of ANFs revealed three ANF pools: 1) a highly ouabain-sensitive pool, which does not participate in either CAP threshold or amplitude, 2) a less sensitive pool, which only encoded CAP amplitude, and 3) a ouabain-resistant pool, required for CAP threshold and amplitude. Remarkably, distribution of the three pools was similar to the SR-based ANF distribution (low-, medium-, and high-SR fibers), suggesting that the low-SR fiber loss leaves the CAP unaffected. Single-unit recordings from the auditory nerve confirmed this hypothesis and further showed that it is due to the delayed and broad first spike latency distribution of low-SR fibers. In addition to unraveling the neural mechanisms that encode CAP, our computational simulation of an assembly of guinea pig ANFs generalizes and extends our experimental findings to different species of mammals. Altogether, our data demonstrate that substantial ANF loss can coexist with normal hearing threshold and even unchanged CAP amplitude.

Contralateral Sound Stimulation Suppresses the Compound Action Potential from the Auditory Nerve in Humans

2002 ◽  
Vol 23 (5) ◽  
pp. 784-788 ◽  
Author(s):  
René Chabert ◽  
Jacques Magnan ◽  
Jean–Gabriel Lallemant ◽  
Alain Uziel ◽  
Jean–Luc Puel
Keyword(s):  
Action Potential ◽  
Auditory Nerve ◽  
Compound Action Potential ◽  
Sound Stimulation ◽  
Compound Action
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