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 Parameters for Applying the Brainstem Auditory Evoked Potential with Speech Stimulus: Systematic Review

2017 ◽  
Vol 22 (04) ◽  
pp. 460-468 ◽  
Author(s):  
Luísa Gabriel ◽  
Luíza Vernier ◽  
Maria Ferreira ◽  
Adriana Silveira ◽  
Márcia Machado
Keyword(s):  
Systematic Review ◽  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Sampling Rate ◽  
Presentation Rate ◽  
Auditory Evoked Potential ◽  
Speech Stimulus ◽  
Brainstem Auditory Evoked Potential

Introduction Studies using the Brainstem Auditory Evoked Potential with speech stimulus are increasing in Brazil, and there are divergences between the methodologies used for testing. Objectives To analyze the parameters used in the study of the Brainstem Auditory Evoked Potentials with speech stimulus. Data Synthesis The survey was performed using electronic databases. The search strategy was as follows: “Evoked potentials, auditory” OR “Brain stem” OR “Evoked potentials, auditory, brain stem” AND “Speech.” The survey was performed from June to July of 2016. The criteria used for including articles in this study were: being written in Portuguese, English or Spanish; presenting the description of the testing parameters and the description of the sample. In the databases selected, 2,384 articles were found, and 43 articles met all of the inclusion criteria. The predominance of the following parameters was observed to achieve the potential during study: stimulation with the syllable /da/; monaural presentation with greater use of the right ear; intensity of 80 dB SPL; vertical placement of electrodes; use of in-ear headphones; patient seated, distracted in awake state; alternating polarity; use of speech synthesizer software for the elaboration of stimuli; presentation rate of 10.9/s; and sampling rate of 20 kHz. Conclusions The theme addressed in this systematic review is relatively recent. However, the results are significant enough to encourage the use of the procedure in clinical practice and advise clinicians about the most used procedures in each parameter.

scholarly journals Enhancement of Auditory-evoked Potentials in Musicians Reflects an Influence of Expertise but not Selective Attention

2008 ◽  
Vol 20 (12) ◽  
pp. 2238-2249 ◽  
Author(s):  
Simon Baumann ◽  
Martin Meyer ◽  
Lutz Jäncke
Keyword(s):  
Selective Attention ◽  
Auditory Cortex ◽  
Evoked Potentials ◽  
Time Course ◽  
Auditory Evoked Potentials ◽  
Sine Wave ◽  
Event Related Potential ◽  
Auditory Evoked Responses ◽  
Density Mapping ◽  
Sound Features

Instrumental tones and, in some instances, simple sine-wave tones were shown to evoke stronger auditory-evoked responses in musicians compared to nonmusicians. This effect was taken as an example for plasticity in the auditory cortex elicited by training. To date, however, it is unknown whether an enlarged cortical representation for (instrumental) tones or increased neuronal activity provoked by focused attention in musicians accounts for the reported difference. In an attempt to systematically investigate the influence of attention on the processing of simple sine wave and instrumental tones, we compared auditory-evoked potentials recorded from musicians and nonmusicians. During the electroencephalogram recording, the participants were involved in tasks requiring selective attention to specific sound features such as pitch or timbre. Our results demonstrate that the effect of selective attention on the auditory event-related potential (AEP) has a different time course and shows a different topography than the reproduced effect of music expertise at the N1 component or the previously demonstrated effect at the P2 component. N1 peak potentials were unaffected by attention modulation. These results indicate that the effect of music expertise, which was traced by current density mapping to the auditory cortex, is not primarily caused by selective attention, and it supports the view that increased AEPs on tones in musicians reflect an enlarged neuronal representation for specific sound features of these tones. However, independent from the N1–P2 complex, attention evoked an Nd-like negative component in musicians but not in nonmusicians, which suggests that plasticity also affects top–down processes.

High-frequency Components of Auditory Evoked Potentials Are Detected in Responsive but Not in Unconscious Patients

2005 ◽  
Vol 103 (5) ◽  
pp. 944-950 ◽  
Author(s):  
Bertram Scheller ◽  
Gerhard Schneider ◽  
Michael Daunderer ◽  
Eberhard F. Kochs ◽  
Bernhard Zwissler
Keyword(s):  
Evoked Potentials ◽  
General Anesthesia ◽  
High Frequency ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Auditory Evoked Potential ◽  
General Anesthetics ◽  
Frequency Bands ◽  
Time Frequency ◽  
Frequency Components

Background The dose-dependent suppression of midlatency auditory evoked potentials by general anesthetics has been proposed to measure depth of anesthesia. In this study, perioperatively recorded midlatency auditory evoked potentials were analyzed in a time-frequency space to identify significant changes induced by general anesthesia. Methods Perioperatively recorded auditory evoked potentials of 19 patients, recorded at varying levels of anesthesia, were submitted to a multiscale analysis using the wavelet analysis. Energy contents of the signal were calculated in frequency bands 0-57.1 Hz, 57.1-114.3 Hz, 114.3-228.6 Hz, and 228.6-457.1 Hz. A Friedman test and a Dunn multiple comparisons test were performed to identify significant differences. Results Statistical evaluation showed a highly significant decrease of the wavelet energies for the frequency bands 57.1-114.3 Hz (P < 0.0001), 114.3-228.6 Hz (P < 0.0001), and 228.6-457.1 Hz (P < 0.0001) for the measuring points representing deep general anesthesia. This decrease is accompanied by a decrease in the wavelet energy of the frequency band 0-57.1 Hz of no statistical significance (P = 0.021) (level of significance set to P = 0.01). The changes are most prominent in the poststimulus interval between 10 and 30 ms. Conclusions This study describes the presence of high-frequency components of the auditory evoked potential. The amount of these components is higher during responsiveness when compared to unconsciousness. Temporal localization of the high-frequency components within the auditory evoked potential shows that they represent a response to the auditory stimulus. Further studies are required to identify the source of these high-frequency components.

scholarly journals Abnormalities in auditory evoked potentials of 75 patients with Arnold-Chiari malformations types I and II

2006 ◽  
Vol 64 (3a) ◽  
pp. 619-623 ◽  
Author(s):  
Paulo Sergio A. Henriques Filho ◽  
Riccardo Pratesi
Keyword(s):  
Evoked Potentials ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Amplitude Ratio ◽  
Auditory Evoked Potential ◽  
Type I ◽  
Auditory Pathways ◽  
Degree Of Severity ◽  
Chiari Malformations

OBJECTIVE: To evaluate the frequency and degree of severity of abnormalities in the auditory pathways in patients with Chiari malformations type I and II. METHOD: This is a series-of-case descriptive study in which the possible presence of auditory pathways abnormalities in 75 patients (48 children and 27 adults) with Chiari malformation types I and II were analyzed by means of auditory evoked potentials evaluation. The analysis was based on the determination of intervals among potentials peak values, absolute latency and amplitude ratio among potentials V and I. RESULTS: Among the 75 patients studied, 27 (36%) disclosed Arnold-Chiari malformations type I and 48 (64%) showed Arnold-Chiari malformations type II. Fifty-three (71%) of these patients showed some degree of auditory evoked potential abnormalities. Tests were normal in the remaining 22 (29%) patients. CONCLUSION: Auditory evoked potentials testing can be considered a valuable instrument for diagnosis and evaluation of brain stem functional abnormalities in patients with Arnold-Chiari malformations type I and II. The determination of the presence and degree of severity of these abnormalities can be contributory to the prevention of further handicaps in these patients either through physical therapy or by means of precocious corrective surgical intervention.

scholarly journals Auditory Evoked Potentials P50: Pure-tones vs Clicks. There is a Similar Supression?

2020 ◽  
pp. 32-39
Author(s):  
PhD M.D, Seidel Guerra López ◽  
M.D, María de Los A. Pedroso Rodríguez ◽  
M.D, Diego Cantero ◽  
Gilvan Aguiar da Silva
Keyword(s):  
Evoked Potentials ◽  
Pure Tone ◽  
Auditory Evoked Potentials ◽  
Sound Pressure ◽  
Evoked Potential ◽  
Stimulus Frequency ◽  
Auditory Evoked Potential ◽  
Pure Tones ◽  
Middle Latency ◽  
The Brain

Objective: Clinical application of middle-latency auditory evoked potential (MLAEPs) has been increasing, highlighting the importance of understanding the nature of P50, a component of middle-latency auditory evoked potential. We manipulated stimulus frequency bands in auditory stimuli in order to investigate the nature of P50 in human auditory evoked potentials. Methods: Two paradigms have been used to obtain P50: one is a conditioning /testing paradigm in which paired of pure tone (1000Hz) are delivered, and the other was presented paired of clicks, both with an intensity of 60 dB sound pressure level above the auditory threshold. A total of 30 healthy volunteers were recruited for this study among Center of genetic engineering (fifteen man and fifteen women, mean age of 36, 5). All without consumption of caffeine, cigarettes and drugs. Results: No statistically significant differences occurred between the P50 amplitudes and latencies for the pure tone and those for the clicks. Conclusions: Our present results indicate that P50 in humans may reflect a feed-forward mechanism of the brain where a preceding stimulus drives sensory gating mechanisms in preparation for a second stimulus, but the contained frequency doesn't influence on the P50. Both types (tones or clicks) can be used in the exploration of patient with this evoked potential.

Recovery Function of the Late Auditory Evoked Potential in Cochlear Implant Users and Normal-Hearing Listeners

2009 ◽  
Vol 20 (07) ◽  
pp. 397-408 ◽  
Author(s):  
Fawen Zhang ◽  
Ravi N. Samy ◽  
Jill M. Anderson ◽  
Lisa Houston
Keyword(s):  
Cochlear Implant ◽  
Evoked Potentials ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Aging Effect ◽  
Normal Hearing ◽  
Temporal Coding ◽  
Auditory Evoked Potential ◽  
Recovery Function ◽  
Probe Response

Background: It has been theorized that neural recovery is related to temporal coding of speech sounds. The recovery function of cortically generated auditory evoked potentials has not been investigated in cochlear implant (CI) users. Purpose: This study characterized the recovery function of the late auditory evoked potential (LAEP) using a masker–probe paradigm in postlingually deafened adult CI users and young normal-hearing (NH) listeners. Research Design: A case-control study of the late auditory evoked potentials using electrophysiological technique was performed. The LAEP was evoked by 1 kHz tone bursts presented in pairs, with the first stimuli as the maskers and the second stimuli as the probes. The masker–probe intervals (MPIs) were varied at 0.7, 1, 2, 4, and 8 sec, with an interpair interval of 12 sec. Study Sample: Nine CI users and nine NH listeners participated in this study. Data Collection and Analysis: The normalized amplitude from the probe response relative to the masker response was plotted as a function of the MPI to form a recovery function. The latency shift for the probe response relative to the masker response was calculated. Results: The recovery function was approximately linear in log scale of the MPI in NH listeners, while it showed somewhat different recovery patterns with a large intersubject variability in CI users. Specifically, although the probe response was approximately 60 percent of the masker response for the MPI of 0.7 sec in both groups, the recovery function of CI users displayed a nonlinear pattern, with a steeper slope than that of NH listeners. The probe response completely recovered at the MPI of 4 sec in NH listeners and at the MPI of 2 sec in CI users. N1 and P2 latencies from probe responses were shorter than those from masker responses in NH listeners, while no latency difference was found between probe responses and masker responses in CI users. Conclusions: Our interpretation of these findings is that the faster recovery of the LAEP in CI users is related to abnormal adaptation mechanisms and a less prominent role of the components with longer latencies in the LAEP of CI users. Other mechanisms such as the compromised inhibitory regulation in the auditory system and the aging effect in CI users might also play a role. More research needs to be done to determine whether the slope of the LAEP recovery function is correlated with speech-perception performance.

Brain 5-HT function in bipolar affective disorder

2000 ◽  
Vol 12 (3) ◽  
pp. 91-95
Author(s):  
A.H. Young ◽  
J.H. Hughes ◽  
C.H. Ashton
Keyword(s):  
Bipolar Disorder ◽  
Power Spectrum ◽  
Evoked Potentials ◽  
Auditory Evoked Potentials ◽  
Auditory Evoked Potential ◽  
Brain Serotonin ◽  
Acute Tryptophan Depletion ◽  
Tryptophan Depletion ◽  
Eeg Activity ◽  
Bipolar Patients

ABSTRACTBackground: Previous studies suggest that brain serotonin neurotransmission may mediate the actions of lithium carbonate. Acute tryptophan depletion (ATD) reduces brain serotonin and allows the study of this neurotransmitter in patient groups. Serotonin modulates electroencephalographic (EEG) activity, which is abnormal in bipolar disorder, and EEG abnormalities persist in euthymic bipolar patients. The EEG may therefore be a sensitive marker of 5-HT function in bipolar disorder.Aims: This study examined the effects of ATD on mood, suicidal ideation and EEG activity in bipolar patients who were symptomatically stable on lithium.Methods: 19 subjects satisfying DSM-IV criteria for bipolar I disorder participated in a within-subject, double-blind, placebo-controlled random-order crossover study. Following acute tryptophan depletion (induced by a 100g amino acid drink following an overnight fast) symptoms were evaluated, quantitative power spectrum brain mapping and measurement of auditory evoked potentials were carried out.Results: ATD produced a significant fall in the amplitude of N1P2 and P300 components of the auditory evoked potential, but no significant changes in the power spectrum. There was an 83% reduction in plasma tryptophan (p<0.05, paired t-test) after the depleting but not the control drink. No significant changes in mood or suicidally scores were recorded after ATD.Conclusions: ATD attenuates auditory evoked potentials in bipolar disorder but does not reverse lithium's effects on mood and suicidally in bipolar disorder.

scholarly journals Middle latency auditory evoked potential in child population

2016 ◽  
Vol 26 (3) ◽  
pp. 368 ◽  
Author(s):  
Anna Caroline Silva de Oliveira ◽  
Simone Fiuza Regaçone ◽  
Ana Claudia Figueiredo Frizzo
Keyword(s):  
Evoked Potentials ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Auditory Evoked Potential ◽  
Electrode Position ◽  
Potential System ◽  
Significant Difference ◽  
Left And Right ◽  
Middle Latency ◽  
The Right

Introduction: The middle-latency auditory evoked potential is used to evaluate any abnormality that might impair the central auditory pathways, which are situated between the brain stem and the primary auditory cortex. Objective: To analyse the middle-latency auditory evoked potentials in children. Methods: This is a descriptive and cross-sectional study. Pure-tone audiometry was performed, and if no change was detected, Biologic’s portable Evoked Potential System (EP) was used to measure auditory evoked potentials. The identification of the responses was performed using electrodes positioned at C3 and C4 (left and right hemispheres) in reference to ears A1 and A2 (left and right earlobe). These were ipsilaterally and contralaterally paired and landed at Fpz (forehead), in two steps, with alternating stimulation of the right and left ears. Results: In this study, there was 100% detectability of the Na, Pa, and Nb components and interamplitude Na–Pa. This study compared different electrode leads, and there was no significant difference between the different electrode positions studied for the right and left ears in the studied population. Conclusion: It was concluded that the examination of middle-latency evoked potential is steady and feasible for the studied age group regardless of electrode position.

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