Evolutionary elongation of the time window of auditory cortical processing: Comparison of effects of stimulus time parameters on human and macaque scalp auditory evoked potentials

2016 ◽  
Vol 140 (4) ◽  
pp. 3155-3155
Author(s):  
Kosuke Itoh ◽  
Masafumi Nejime ◽  
Naho Konoike ◽  
Katsuki Nakamura ◽  
Tsutomu Nakada
Keyword(s):  
Evoked Potentials ◽  
Auditory Evoked Potentials ◽  
Time Window ◽  
Cortical Processing ◽  
Time Parameters ◽  
Stimulus Time

scholarly journals A Structured ICA-based Process for Removing Auditory Evoked Potentials Reveals TMS-evoked Potentials and TMS-modulated Oscillations

2021 ◽  
Author(s):  
Jessica M. Ross ◽  
Recep A. Ozdemir ◽  
Shu Jing Lian ◽  
Peter J. Fried ◽  
Eva M. Schmitt ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Time Course ◽  
Auditory Evoked Potentials ◽  
Time Window ◽  
Auditory Evoked Potential ◽  
Cosine Similarity ◽  
Similarity Analysis ◽  
Stimulation Site ◽  
Individual Subject ◽  
Site Specific

Abstract Background: Transcranial magnetic stimulation (TMS)-evoked potentials (TEPs), recorded using electroencephalography (EEG), reflect a combination of TMS-induced cortical activity and multi-sensory responses to TMS. The auditory evoked potential (AEP) is a high-amplitude sensory potential—evoked by the “click” sound produced by every TMS pulse—that can dominate the TEP and obscure observation of other neural components. The AEP is peripherally evoked and therefore should not be stimulation site specificObjectives/Methods: We address the problem of disentangling the peripherally evoked AEP of the TEP from components evoked by cortical stimulation and ask whether removal of AEP enables more accurate isolation of TEP. We hypothesized that isolation of the AEP using Independent Components Analysis (ICA) would reveal features that are stimulation site specific and unique individual features. In order to improve the effectiveness of ICA for removal of AEP from the TEP, and thus more clearly separate the transcranial-evoked and non-specific TMS-modulated potentials, we merged sham and active TMS datasets representing multiple stimulation conditions, removed the resulting AEP component, and evaluated performance across different sham protocols and clinical populations using reduction in Global and Local Mean Field Potentials (GMFA/LMFA) and cosine similarity analysis.Results: We show that removing AEPs significantly reduced GMFA and LMFA in the post-stimulation TEP (14 to 400 ms), driven by time windows consistent with the N100 and P200 temporal characteristics of AEPs. Cosine similarity analysis supports that removing AEPs reduces TEP similarity between subjects and reduces TEP similarity between stimulation conditions. Similarity is reduced most in a mid-latency window consistent with the N100 time-course, but nevertheless remains high in this time window. Residual TEP in this window has a time-course and topography unique from AEPs, which follow-up analyses suggest could be a modulation in the alpha band that is not stimulation site specific but is unique to individual subject.Conclusion(s): We show, using two datasets and two implementations of sham, evidence in cortical topography, TEP time-course, GMFA/LMFA and cosine similarity analyses that this procedure is effective and conservative in removing the AEP from TEP, and thereby reveals better defined TMS-evoked activity. We show TEP remaining in early, mid and late latencies. The early response is site and subject specific. Later responses are consistent with TMS-modulated alpha activity that is not site specific but is unique to the individual. TEP remaining after removal of AEP is unique and can provide insight into TMS-evoked potentials and other modulated oscillatory dynamics.

scholarly journals A Pilot Study on Cortical Auditory Evoked Potentials in Children: Aided CAEPs Reflect Improved High-Frequency Audibility with Frequency Compression Hearing Aid Technology

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Danielle Glista ◽  
Vijayalakshmi Easwar ◽  
David W. Purcell ◽  
Susan Scollie
Keyword(s):  
Evoked Potentials ◽  
Hearing Aids ◽  
Auditory Evoked Potentials ◽  
Time Window ◽  
Hearing Aid ◽  
Older Children ◽  
Frequency Compression ◽  
Cortical Responses ◽  
Cortical Auditory Evoked Potentials ◽  
Hearing Aid Benefit

Background. This study investigated whether cortical auditory evoked potentials (CAEPs) could reliably be recorded and interpreted using clinical testing equipment, to assess the effects of hearing aid technology on the CAEP.Methods. Fifteen normal hearing (NH) and five hearing impaired (HI) children were included in the study. NH children were tested unaided; HI children were tested while wearing hearing aids. CAEPs were evoked with tone bursts presented at a suprathreshold level. Presence/absence of CAEPs was established based on agreement between two independent raters.Results. Present waveforms were interpreted for most NH listeners and all HI listeners, when stimuli were measured to be at an audible level. The younger NH children were found to have significantly different waveform morphology, compared to the older children, with grand averaged waveforms differing in the later part of the time window (the N2 response). Results suggest that in some children, frequency compression hearing aid processing improved audibility of specific frequencies, leading to increased rates of detectable cortical responses in HI children.Conclusions. These findings provide support for the use of CAEPs in measuring hearing aid benefit. Further research is needed to validate aided results across a larger group of HI participants and with speech-based stimuli.

Auditory Evoked Potentials

1991 ◽  
Vol 24 (2) ◽  
pp. 349-370 ◽  
Author(s):  
Roger A. Ruth ◽  
Paul R. Lambert
Keyword(s):  
Evoked Potentials ◽  
Auditory Evoked Potentials
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