Neural Mechanisms of Hearing Recovery for Cochlear-Implanted Patients: An Electroencephalogram Follow-Up Study.

Songjian Wang,Xueqing Chen,Xinxing Fu,Meng Lin,Lili Yan,Liwei Sun,Chunlin Li,Xu Zhang

doi:10.3389/fnins.2020.624484

Songjian Wang, Xueqing Chen + Show 6 more

Open Access

https://doi.org/10.3389/fnins.2020.624484

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Abstract

BackgroundPatients with severe profound hearing loss could benefit from cochlear implantation (CI). However, the neural mechanism of such benefit is still unclear. Therefore, we analyzed the electroencephalogram (EEG) and behavioral indicators of auditory function remodeling in patients with CI. Both indicators were sampled at multiple time points after implantation (1, 90, and 180 days).MethodsFirst, the speech perception ability was evaluated with the recording of a list of Chinese words and sentences in 15 healthy controls (HC group) and 10 patients with CI (CI group). EEG data were collected using an oddball paradigm. Then, the characteristics of event-related potentials (ERPs) and mismatch negative (MMN) were compared between the CI group and the HC group. In addition, we analyzed the phase lag indices (PLI) in the CI group and the HC group and calculated the difference in functional connectivity between the two groups at different stages after implantation.ResultsThe behavioral indicator, speech recognition ability, in CI patients improved as the implantation time increased. The MMN analysis showed that CI patients could recognize the difference between standard and deviation stimuli just like the HCs 90 days after cochlear implantation. Comparing the latencies of N1/P2/MMN between the CI group and the HC group, we found that the latency of N1/P2 in CI patients was longer, while the latency of MMN in CI users was shorter. In addition, PLI-based whole-brain functional connectivity (PLI-FC) showed that the difference between the CI group and the HC group mainly exists in electrode pairs between the bilateral auditory area and the frontal area. Furthermore, all those differences gradually decreased with the increase in implantation time.ConclusionThe N1 amplitude, N1/P2/MMN latency, and PLI-FC in the alpha band may reflect the process of auditory function remodeling and could be an objective index for the assessment of speech perception ability and the effect of cochlear implantation.

Highlights

Cochlear implantation (CI) is a well-established means to restore normal hearing for people with severe hearing impairment
The score of the CI users gradually approximated to the healthy controls (HCs) as the implantation time increased
We analyzed the FCz Event-related potentials (ERPs) induced by the standard stimulus and deviation stimulus in CI users when the device was activated, 90 days after device activation, and 180 days after device activation and the HC group

Summary

Introduction

Cochlear implantation (CI) is a well-established means to restore normal hearing for people with severe hearing impairment. For CI users, behavioral measures such as the category of auditory performance score and speech intelligibility rating (SIR) score are the primary methods to evaluate speech perception ability and the effect of implantation. It is hard to apply these methods to people with prelingual deafness or prolonged auditory deprivation and children, since they are unable to complete the speech tests because of their poor communication and cognitive function (Mareike Finke et al, 2016). Patients with severe profound hearing loss could benefit from cochlear implantation (CI). We analyzed the electroencephalogram (EEG) and behavioral indicators of auditory function remodeling in patients with CI. Both indicators were sampled at multiple time points after implantation (1, 90, and 180 days)

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Discussion

Conclusion