The Cochlear Implant EEG Artifact Recorded From an Artificial Brain for Complex Acoustic Stimuli

Abstract

The CI EEG artifact for speech appears more difficult to detect than for simple stimuli. Since the artifact differs across CI users, due to their individual clinical maps, the method presented enables insight into the individual manifestations of the artifact.

Speech-ABRs in cochlear implant recipients: feasibility study

“…two participants (CI02 and CI09) did not resemble speech-ABRs, while responses from the other two participants (CI03 and CI11) were large in amplitude-PAR and did not resemble speech-ABRs (remaining participant figures in Supplement 3, Section 1). In an attempt to verify whether artefact removal was successful for CI07 and CI08, Wagner et al (2018) were approached and agreed to record artefacts based on participant MAPs. Artefacts based on the closest possible approximation to CI MAPs from three MED-EL participants (CI07, CI08 and CI09) were recorded using an artificial-head (details in Supplement 3, Section 2), the same artefact removal was applied to these recorded artefacts and resulting waveforms contained minimal residual artefact (see Figure 3 for one example, and Supplement 3, Section 2, for the other two).…”

“…Although responses from participants with Cochlear Nucleus 22 implants were the appropriate amplitude-BAR and amplitude-PAR plus resembled speech-ABRs, it was difficult to conclude whether responses were artefacts or brainstem responses. CI artefacts from Cochlear Nucleus CIs follow the stimulus envelope (Wagner et al 2018), which would result in waveforms that may resemble speech-ABRs. Given the smaller amplitude CI artefact (Li et al 2010) and that CI artefacts from Cochlear Nucleus CIs follow the stimulus envelope (Wagner et al 2018), it is more likely that responses recorded from participants with Cochlear Nucleus 22 CIs are artefacts rather than speech-ABRs.…”

“…CI artefacts from Cochlear Nucleus CIs follow the stimulus envelope (Wagner et al 2018), which would result in waveforms that may resemble speech-ABRs. Given the smaller amplitude CI artefact (Li et al 2010) and that CI artefacts from Cochlear Nucleus CIs follow the stimulus envelope (Wagner et al 2018), it is more likely that responses recorded from participants with Cochlear Nucleus 22 CIs are artefacts rather than speech-ABRs. Second, Cochlear Nucleus 24 CIs (ACE and MP) resulted in responses that followed the 40 ms [da] envelope.…”

“…This pitch encoding may be sufficient to evoke speech-ABRs, though it may also cause "stimulation bursts" in the recordings resembling the temporal fine structure of the stimulus that remained after artefact removal, resulting in responses containing speech-ABR characteristics. However, when artefact removal was applied to the three artefacts recorded by Wagner et al (2018) using an artificial-head, artefact removal was successful and consequently the obtained traces did not contain speech-ABR characteristics. Indicating that these "stimulation bursts" were not present after artefact removal.…”

“…We thank Dr Michael Stone for his technical advice relating to the revised version of this manuscript, Dr Anita Wagner, Liana Wobben and all the authors of Wagner et al (2018) from the University of Groningen, Groningen, the Netherlands for recording the artefacts, the Auditory Neuroscience Laboratory, Department of Communication Sciences, Northwestern University, Evanston, IL, USA for the provision of stimuli (40 ms [da]) used in this study.…”