Objective The goal of this study was to evaluate the use of interpeak latency (IPL) and its inter-trial variability (VIL) of the electrically evoked compound action potential as potential alternative indicators to the phase locking value (PLV) metric that has previously been used to quantify neural synchrony in the cochlear nerve (CN) of cochlear implant (CI) users.

Design IPLs were compared among children with auditory neuropathy spectrum disorder, cochlear nerve deficiency, or typical sensorineural hearing loss, and postlingually deafened adult CI users. The VIL was assessed only in adults. Their associations with gap detection thresholds (GDT), speech perception scores, and PLVs were examined.

Results The VIL, but not the IPL, was correlated with GDT, speech perception outcomes, and the PLV. Group, age and electrode location effects on the IPL could not be explained solely by neural synchrony.

Conclusions The VIL, but not the IPL, is indicative of neural synchrony in the CN. Similar to the PLV, the VIL is affected by the CI’s sampling rate and internal noise.

The authors have declared no competing interest.

This work was supported by grants from the National Institutes of Health awarded to SH [grant numbers 1R01DC016038 and 1R01 DC017846]. Ian C. Bruce was supported by NSERC Discovery Grant RGPIN-2018-05778. The funding organizations played no role in designing or conducting the study, collecting or analyzing the data, interpreting the results, preparing the manuscript, reviewing or approving its content, or deciding to submit it for publication.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The data reported in this study were collected for the projects that were approved by the biomedical Institutional Review Board (IRB) of The Ohio State University (IRB study number: 2017H0131, 2018H0344 and 2018N0005; PI: Shuman He), the IRB of the University of North Carolina at Chapel Hill (IRB study number: 12 1737; PI: Shuman He), and the IRB of Shandong ENT Hospital (IRB study number: SENTP, 2016 2; PI: Lei Xu).

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Conflict of Interest: None.

IRB information: The data reported in this study were collected for the projects that were approved by the biomedical Institutional Review Board (IRB) of The Ohio State University (IRB study #: 2017H0131, 2018H0344 and 2018N0005; PI: Shuman He), the IRB of the University of North Carolina at Chapel Hill (IRB study #: 12–1737; PI: Shuman He), and the IRB of Shandong ENT Hospital (IRB study #: SENTP, 2016-2; PI: Lei Xu).

Source of Funding: This work was supported by grants from the National Institutes of Health awarded to SH [grant numbers 1R01DC016038 and 1R01 DC017846]. Ian C. Bruce was supported by NSERC Discovery Grant #RGPIN-2018-05778. The funding organizations played no role in designing or conducting the study, collecting or analyzing the data, interpreting the results, preparing the manuscript, reviewing or approving its content, or deciding to submit it for publication.

All data used in the present study are available upon reasonable request to the authors.