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Fulltext Evoked response study among Malaysian multiple sclerosis patients

Tan CT, Leong S

Singapore Med J, 1992 Dec;33(6):575-80.
PMID: 1488664

A study of visual evoked potential (VEP), brainstem evoked potential (BAEP) and median nerve somatosensory evoked potential (SSEP) in 26 Malaysian patients with clinically definite Multiple Sclerosis (MS). This study showed an overall high rate of abnormality, with 85% of patients for VEP, 31% for BAEP and 65% for median nerve SSEP. The rate of abnormality was particularly high for patients who were symptomatic, reaching 100% of patients for VEP, 50% of patients in BAEP, 83% of nerves for median nerve SSEP. The rate of abnormality among those who were asymptomatic was lower, varying from 32% of eyes in VEP, 27% of patients in BAEP and 31% of nerves in median nerve SSEP. Three out of 10 patients with optic spinal form of MS have abnormal BAEP. These show the usefulness of the evoked potential studies in confirming the clinical lesions as well as demonstrating subclinical involvement. The rate of abnormal evoked responses for the asymptomatic patients in this study is generally lower than that published elsewhere.

Matched MeSH terms: Evoked Potentials*; Evoked Potentials, Somatosensory; Evoked Potentials, Visual; Evoked Potentials, Auditory, Brain Stem
Executive function measures of participants with mild cognitive impairment: Systematic review and meta-analysis of event-related potential studies

Che J, Cheng N, Jiang B, Liu Y, Liu H, Li Y, et al.

Int J Psychophysiol, 2024 Mar;197:112295.
PMID: 38266685 DOI: 10.1016/j.ijpsycho.2023.112295

OBJECTIVE: Objective measurements of executive functions using event-related potential (ERP) may be used as markers for differentiating healthy controls (HC) from patients with mild cognitive impairment (MCI). ERP is non-invasive, cost-effective, and affordable. Older adults with MCI demonstrate deteriorated executive function, serving as a potentially valid neurophysiological marker for identifying MCI. We aimed to review published ERP studies on executive function in older adults with MCI and summarize the performance differences by component between healthy older adults and older adults with MCI.
METHODS: Eight electronic databases (Web of Science, PubMed, ScienceDirect, American Psychological Association PsycNet, Cochrane Library, Scopus, Embase, and Ovid) were searched for the study. Articles published from January 1 to December 31, 2022, were considered for this review. A random-effects meta-analysis and between-study heterogeneity analysis were conducted using Comprehensive Meta-Analysis V3.0 software.
RESULTS: We identified 7829 articles of which 28 met the full inclusion criteria and were included in the systematic review and analyses. Our pooled analysis suggested that participants with MCI can be differentiated from HC by significant P200, P300, and N200 latencies. The P100 and P300 amplitudes were significantly smaller in participants with MCI when compared with those in the HCs, and the patients with MCI showed increased N200 amplitudes. Our findings provide new insights into potential electrophysiological biomarkers for diagnosing MCI.

Matched MeSH terms: Evoked Potentials/physiology
The effects of audio stimuli on auditory-evoked potential in normal hearing Malay adults

Ibrahim IA, Ting HN, Moghavvemi M

Int J Health Sci (Qassim), 2018 9 12;12(5):25-34.
PMID: 30202405

Objectives: The hearing process in the brain is very complicated and hard to solve. However, an understanding of the hearing process is an essential issue and needed in many rehabilitation or treatment applications. This study investigates and compares the effects of simple and complex sounds on latency and amplitude of various event-related potential (ERP) components to male ethnic Malay adults. Comparisons were made with previous studies.
Materials and Methods: Simple and complex sounds were used (pure tones and the naturally produced Malay consonant-vowels [CVs]) to evoke the cortical auditory-evoked potential (CAEP) signals. Moreover, this study analyzed the influence of related CAEP components that are distinct to the selected population and determined which of the ERP components among (CAEP) components is most affected by the two distinct stimuli. Moreover, the study used classification algorithms to discover the ability of the brain in distinguishing CAEP evoked by stimuli contrasts.
Results: The results showed some resemblance between our results and ERP waveforms outlined in previous studies conducted on native speakers of English. On the other hand, it was also observed that the P1 and N2 had a significant effect in amplitude due to different stimulus.
Conclusion: The results show high classification accuracy for the brain to distinguish auditory stimuli. Moreover, the results indicated some resemblance to previous studies conducted on native English speakers using similar tones and English CV stimuli. However, the amplitudes and latencies of the P1 were found to have a significant difference due to stimuli complexity.

Matched MeSH terms: Evoked Potentials; Evoked Potentials, Auditory
Exploring the temporal dynamics of inhibition of return using steady-state visual evoked potentials

Lim A, Janssen SMJ, Satel J

Cogn Affect Behav Neurosci, 2020 12;20(6):1349-1364.
PMID: 33236297 DOI: 10.3758/s13415-020-00846-w

Inhibition of return is characterized by delayed responses to previously attended locations when the interval between stimuli is long enough. The present study employed steady-state visual evoked potentials (SSVEPs) as a measure of attentional modulation to explore the nature and time course of input- and output-based inhibitory cueing mechanisms that each slow response times at previously stimulated locations under different experimental conditions. The neural effects of behavioral inhibition were examined by comparing post-cue SSVEPs between cued and uncued locations measured across two tasks that differed only in the response modality (saccadic or manual response to targets). Grand averages of SSVEP amplitudes for each condition showed a reduction in amplitude at cued locations in the window of 100-500 ms post-cue, revealing an early, short-term decrease in the responses of neurons that can be attributed to sensory adaptation, regardless of response modality. Because primary visual cortex has been found to be one of the major sources of SSVEP signals, the results suggest that the SSVEP modulations observed were caused by input-based inhibition that occurred in V1, or visual areas earlier than V1, as a consequence of reduced visual input activity at previously cued locations. No SSVEP modulations were observed in either response condition late in the cue-target interval, suggesting that neither late input- nor output-based IOR modulates SSVEPs. These findings provide further electrophysiological support for the theory of multiple mechanisms contributing to behavioral cueing effects.

Matched MeSH terms: Evoked Potentials, Visual*
Effects of Stimulus Repetition Rates on the Auditory Brainstem Response to Level-Specific CE-Chirp in Normal-Hearing Adults

Dzulkarnain AAA, Shahrudin FA, Jamal FN, Marzuki MN, Mazlan MNS

Am J Audiol, 2020 Dec 09;29(4):838-850.
PMID: 32966099 DOI: 10.1044/2020_AJA-20-00049

Purpose The purpose of this study is to investigate the influence of stimulus repetition rates on the auditory brainstem response (ABR) to Level-Specific (LS) CE-Chirp and click stimuli at multiple intensity levels in normal-hearing adults. Method A repeated-measure study design was used on 13 normal-hearing adults. ABRs were acquired from the study participants using LS CE-Chirp and click stimuli at four stimulus repetition rates (19.1, 33.3, 61.1, and 81.1 Hz) and four intensity levels (80, 60, 40, and 20 dB nHL). The ABR test was stopped at 40-nV residual noise level. Results High-stimulus repetition rates caused the ABR latencies to be longer and have reduced amplitudes in both ABR to LS CE-Chirp and click stimuli. The ABR to LS CE-Chirp Wave I, III, and V amplitudes were larger than ABR to click in almost all the stimulus repetition rates. However, there were no differences in the number of averages required to reach the stopping criterion between ABR to LS CE-Chirp and click stimulus, and between high-stimulus repetition rates and low-stimulus repetition rates. Conclusion The LS CE-Chirp at standard low-stimulus repetition rates can be used to elicit ABR for both neurodiagnostic and threshold seeking procedure.

Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem*
Statistical verification on the effect of hearing loss on speech-evoked auditory brainstem response

Zakaria MN

Int J Pediatr Otorhinolaryngol, 2017 10;101:264.
PMID: 28843698 DOI: 10.1016/j.ijporl.2017.08.016
Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem*
Fulltext Transcranial Electrical Motor Evoked Potential in Predicting Positive Functional Outcome of Patients after Decompressive Spine Surgery: Review on Challenges and Recommendations towards Objective Interpretation

Jamaludin MR, Lai KW, Chuah JH, Zaki MA, Hum YC, Tee YK, et al.

Behav Neurol, 2021;2021:2684855.
PMID: 34777631 DOI: 10.1155/2021/2684855

Spine surgeries impose risk to the spine's surrounding anatomical and physiological structures especially the spinal cord and the nerve roots. Intraoperative neuromonitoring (IONM) is a technology developed to monitor the integrity of the spinal cord and the nerve roots via the surgery. Transcranial motor evoked potential (TcMEP) (one of the IONM modalities) is adopted to monitor the integrity of the motor pathway of the spinal cord and the motor nerve roots. Recent research suggested that the IONM is conducive as a prognostic tool towards the patient's functional outcome. This paper summarizes the researches of IONM being adopted as a prognostic tool. In addition, this paper highlights the problems associated with the signal parameters as the improvement criteria in the previous researches. Lastly, we review the challenges of TcMEP to achieve a prognostic tool focusing on the factors that could interfere with the generation of a stable TcMEP response. The final section will discuss recommendations for IONM technology to achieve an objective prognostic tool.

Matched MeSH terms: Evoked Potentials, Motor*
Fulltext Feedback-related potentials in a gambling task with randomised reward

Mushtaq F, Guillen PP, Wilkie RM, Mon-Williams MA, Schaefer A

Data Brief, 2016 Mar;6:378-85.
PMID: 26862585 DOI: 10.1016/j.dib.2015.11.060

Event-related potentials (ERPs) time-locked to decision outcomes are reported. Participants engaged in a gambling task (see [1] for details) in which they decided between a risky and a safe option (presented as different coloured shapes) on each trial (416 in total). Each decision was associated with (fully randomised) feedback about the reward outcome (Win/Loss) and its magnitude (varying as a function of decision response; 5-9 points for Risky decisions and 1-4 points for Safe decisions). Here, we show data demonstrating: (a) the influence of Win feedback in the preceding outcome (Outcome t-1) on activity related to the current outcome (Outcome t ); (b) difference wave analysis for outcome expectancy- separating Expected Outcomes (consecutive Loss trials subtracted from consecutive reward) from Unexpected Outcomes (subtracting Loss t-1Win t trials from Win t-1Loss t trials); (c) difference waves separating Switch and Stay responses for Outcome Expectancy; (d) the effect of magnitude induced by decisions (Risk t vs. Safe t ) on Outcome Expectancy; and finally, (e) expectations reflected by response switch direction (Risk to Safe responses vs. Safe to Risk t ) on the FRN at Outcome t .

Matched MeSH terms: Evoked Potentials
Fulltext Can Brain Waves Really Tell If a Product Will Be Purchased? Inferring Consumer Preferences From Single-Item Brain Potentials

Goto N, Lim XL, Shee D, Hatano A, Khong KW, Buratto LG, et al.

Front Integr Neurosci, 2019;13:19.
PMID: 31316357 DOI: 10.3389/fnint.2019.00019

Recent research has shown that event-related brain potentials (ERPs) recorded while participants view lists of different consumer goods can be modulated by their preferences toward these products. However, it remains largely unknown whether ERP activity specific to a single consumer item can be informative about whether or not this item will be preferred in a shopping context. In this study, we examined whether single-item ERPs could reliably predict consumer preferences toward specific consumer goods. We recorded scalp EEG from 40 participants while they were viewing pictures of consumer goods and we subsequently asked them to indicate their preferences for each of these items. Replicating previous results, we found that ERP activity averaged over the six most preferred products was significantly differentiated from ERP activity averaged across the six least preferred products for three ERP components: The N200, the late positive potential (LPP) and positive slow waves (PSW). We also found that using single-item ERPs to infer behavioral preferences about specific consumer goods led to an overall predictive accuracy of 71%, although this figure varied according to which ERPs were targeted. Later positivities such as the LPP and PSW yielded relatively higher predictive accuracy rates than the frontal N200. Our results suggest that ERPs related to single consumer items can be relatively accurate predictors of behavioral preferences depending on which type of ERP effects are chosen by the researcher, and ultimately on the level of prediction errors that users choose to tolerate.

Matched MeSH terms: Evoked Potentials
Fulltext Acute impending compartment syndrome during elective spine surgery: a rare occurrence

Yeap TB, Shabani NS, Bong CP, Tan HS

BMJ Case Rep, 2021 Jul 13;14(7).
PMID: 34257132 DOI: 10.1136/bcr-2021-244358

Intraoperative impending compartment syndrome (ICS) is an extremely rare but lethal occurrence that can involve the upper and/or lower limb(s). It commonly occurs in patients who undergo anaesthesia in various special positions such as lithotomy, lateral decubitus or prone. We present a patient who developed an ICS of his left forearm during a cervical spine surgery in prone position. This devastating condition was fortunately identified when the pulse oximetry, intra-arterial wave form and motor-evoked potentials signal disappeared abruptly from our monitors. We discuss our perioperative challenges and management for the patient which had eventually saved the patient's limb.

Matched MeSH terms: Evoked Potentials, Motor
Fulltext How Much We Think of Ourselves and How Little We Think of Others: An Investigation of the Neuronal Signature of Self-Consciousness between Different Personality Traits through an Event-Related Potential Study

Hassan AB, Begum T, Reza MF, Yusoff N

Malays J Med Sci, 2016 Nov;23(6):70-82.
PMID: 28090181 MyJurnal DOI: 10.21315/mjms2016.23.6.8

Previous studies have revealed that self-related tasks (items) receive more attention than non-self-related, and that they elicit event-related potential (ERP) components with larger amplitudes. Since personality has been reported as one of the biological correlates influencing these components, as well as our behavioural differences, it is important to examine how it affects our self-consciousness in relation to tasks of varied relevance and the neurological basis.

Matched MeSH terms: Evoked Potentials
A preliminary investigation into the use of an auditory brainstem response (ABR) simulator for training audiology students in waveform analysis

Dzulkarnain AA, Wan Mhd Pandi WM, Wilson WJ, Bradley AP, Sapian F

Int J Audiol, 2014 Aug;53(8):514-21.
PMID: 24702636 DOI: 10.3109/14992027.2014.897763

To determine if a computer simulation can be used to improve the ability of audiology students to analyse ABR waveforms.

Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem*
EEG/ERP adaptive noise canceller design with controlled search space (CSS) approach in cuckoo and other optimization algorithms

Ahirwal MK, Kumar A, Singh GK

IEEE/ACM Trans Comput Biol Bioinform, 2013 Nov-Dec;10(6):1491-504.
PMID: 24407307 DOI: 10.1109/TCBB.2013.119

This paper explores the migration of adaptive filtering with swarm intelligence/evolutionary techniques employed in the field of electroencephalogram/event-related potential noise cancellation or extraction. A new approach is proposed in the form of controlled search space to stabilize the randomness of swarm intelligence techniques especially for the EEG signal. Swarm-based algorithms such as Particles Swarm Optimization, Artificial Bee Colony, and Cuckoo Optimization Algorithm with their variants are implemented to design optimized adaptive noise canceler. The proposed controlled search space technique is tested on each of the swarm intelligence techniques and is found to be more accurate and powerful. Adaptive noise canceler with traditional algorithms such as least-mean-square, normalized least-mean-square, and recursive least-mean-square algorithms are also implemented to compare the results. ERP signals such as simulated visual evoked potential, real visual evoked potential, and real sensorimotor evoked potential are used, due to their physiological importance in various EEG studies. Average computational time and shape measures of evolutionary techniques are observed 8.21E-01 sec and 1.73E-01, respectively. Though, traditional algorithms take negligible time consumption, but are unable to offer good shape preservation of ERP, noticed as average computational time and shape measure difference, 1.41E-02 sec and 2.60E+00, respectively.

Matched MeSH terms: Evoked Potentials*
Single-trial subspace-based approach for VEP extraction

Kamel N, Yusoff MZ, Hani AF

IEEE Trans Biomed Eng, 2011 May;58(5):1383-93.
PMID: 21177154 DOI: 10.1109/TBME.2010.2101073

A signal subspace approach for extracting visual evoked potentials (VEPs) from the background electroencephalogram (EEG) colored noise without the need for a prewhitening stage is proposed. Linear estimation of the clean signal is performed by minimizing signal distortion while maintaining the residual noise energy below some given threshold. The generalized eigendecomposition of the covariance matrices of a VEP signal and brain background EEG noise is used to transform them jointly to diagonal matrices. The generalized subspace is then decomposed into signal subspace and noise subspace. Enhancement is performed by nulling the components in the noise subspace and retaining the components in the signal subspace. The performance of the proposed algorithm is tested with simulated and real data, and compared with the recently proposed signal subspace techniques. With the simulated data, the algorithms are used to estimate the latencies of P(100), P(200), and P(300) of VEP signals corrupted by additive colored noise at different values of SNR. With the real data, the VEP signals are collected at Selayang Hospital, Kuala Lumpur, Malaysia, and the capability of the proposed algorithm in detecting the latency of P(100) is obtained and compared with other subspace techniques. The ensemble averaging technique is used as a baseline for this comparison. The results indicated significant improvement by the proposed technique in terms of better accuracy and less failure rate.

Matched MeSH terms: Evoked Potentials, Visual/physiology*
Pure-tone audiometry and auditory brainstem responses in noise-induced deafness

Noorhassim I, Kaga K, Nishimura K

Am J Otolaryngol, 1996 1 1;17(1):31-5.
PMID: 8801813

PURPOSE: The objective of this study is to find the relationship between pure-tone audiometry results and the auditory brainstem response wave abnormalities.
SUBJECTS AND METHODS: The pure-tone audiometry (PTA) and auditory brainstem responses (ABRs) from 22 patients (44 ears) with diagnosed noise-induced permanent hearing loss were studied. Three indices of PTA were average thresholds of 0.5 kHz/, /1 kHz, and 2 kHz (PTA1); 2 kHz and 4 kHz (PTA2); and 4 kHz (PTA3) were subdivided into 3 thresholds of hearing. Their relationships with ABR results were analysed. The patterns of PTA from various groups of ABR wave patterns were studied.
RESULTS: In this study, the abnormal ABR wave patterns were detected in 72.7% of the ears. The ears with prolonged ABR wave latency, absent early waves, prolong interpeak wave I-V latency was 20.5%, 18.2%, and 21.1%, respectively. Normal ABRs were recorded in 27.3% of the ears despite marked thresholds elevation of the PTA at high frequencies. Other relationships between PTA results and ABR wave results were discussed.
CONCLUSION: There were relationships between severity of noise-induced hearing loss indicated by PTA and the patterns of ABR wave abnormalities among workers with noise-induced permanent hearing loss.

Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem*
Fulltext Local context influences memory for emotional stimuli but not electrophysiological markers of emotion-dependent attention

Barnacle GE, Tsivilis D, Schaefer A, Talmi D

Psychophysiology, 2018 04;55(4).
PMID: 29023754 DOI: 10.1111/psyp.13014

Emotional enhancement of free recall can be context dependent. It is readily observed when emotional and neutral scenes are encoded and recalled together in a "mixed" list, but diminishes when these scenes are encoded separately in "pure" lists. We examined the hypothesis that this effect is due to differences in allocation of attention to neutral stimuli according to whether they are presented in mixed or pure lists, especially when encoding is intentional. Using picture stimuli that were controlled for semantic relatedness, our results contradicted this hypothesis. The amplitude of well-known electrophysiological markers of emotion-related attention-the early posterior negativity (EPN), the late positive potential (LPP), and the slow wave (SW)-was higher for emotional stimuli. Crucially, the emotional modulation of these ERPs was insensitive to list context, observed equally in pure and mixed lists. Although list context did not modulate neural markers of emotion-related attention, list context did modulate the effect of emotion on free recall. The apparent decoupling of the emotional effects on attention and memory, challenges existing hypotheses accounting for the emotional enhancement of memory. We close by discussing whether findings are more compatible with an alternative hypothesis, where the magnitude of emotional memory enhancement is, at least in part, a consequence of retrieval dynamics.

Matched MeSH terms: Evoked Potentials/physiology*
How do Asians perceive Caucasian eyes? Electrophysiological correlates of perceiving racial differences from the eyes region of the face

Yong MH, Lim XL, Schaefer A

Neurosci Lett, 2020 02 16;720:134759.
PMID: 31952988 DOI: 10.1016/j.neulet.2020.134759

Past research has found that several brain event-related potentials (ERPs) were sensitive to the perception of ethnic differences displayed on human faces. This body of research suggests that the phenomenon of "race perception" involves a cascade of cognitive processes that includes both automatic and overt attentional mechanisms. However, most of these studies used stimuli depicting whole faces rather than stimuli depicting separate facial features. Therefore, it is still largely unknown if ERP responses to racial differences are the result of a holistic processing of the whole face, or whether they can be accounted for by the perception of single facial features. To address this issue, we examined whether a single facial feature, the eyes region, can provide sufficient information to trigger known ERP correlates of race perception such as the P2, the N400 and the Late Positive Complex (LPC). Specifically, we showed pictures depicting only the eyes region of Caucasian and Asian faces to a sample of Asian participants. We found that the P2 was larger for other-race (OR) compared to same-race (SR) eyes, and that the N400 was larger for SR compared to OR eyes. The effects on the P2 may suggest an enhanced vigilance response to OR eyes whereas the N400 effect could reflect a signal of familiarity triggered by SR eyes. These results indicate that a specific facial feature, the eyes region, can account for known effects of race perception on early brain potentials. Our findings also indicate that well-known early neural correlates of race perception can be triggered in the absence of a holistic processing of the whole face.

Matched MeSH terms: Evoked Potentials*
Neuroelectrophysiological approaches in heroin addiction research: A review of literatures

Motlagh F, Ibrahim F, Menke JM, Rashid R, Seghatoleslam T, Habil H

J Neurosci Res, 2016 Apr;94(4):297-309.
PMID: 26748947 DOI: 10.1002/jnr.23703

Neuroelectrophysiological properties have been used in human heroin addiction studies. These studies vary in their approach, experimental conditions, paradigms, and outcomes. However, it is essential to integrate previous findings and experimental methods for a better demonstration of current issues and challenges in designing such studies. This Review examines methodologies and experimental conditions of neuroelectrophysiological research among heroin addicts during withdrawal, abstinence, and methadone maintenance treatment and presents the findings. The results show decrements in attentional processing and dysfunctions in brain response inhibition as well as brain activity abnormalities induced by chronic heroin abuse. Chronic heroin addiction causes increased β and α2 power activity, latency of P300 and P600, and diminished P300 and P600 amplitude. Findings confirm that electroencephalography (EEG) band power and coherence are associated with craving indices and heroin abuse history. First symptoms of withdrawal can be seen in high-frequency EEG bands, and the severity of these symptoms is associated with brain functional connectivity. EEG spectral changes and event-related potential (ERP) properties have been shown to be associated with abstinence length and tend to normalize within 3-6 months of abstinence. From the conflicting criteria and confounding effects in neuroelectrophysiological studies, the authors suggest a comprehensive longitudinal study with a multimethod approach for monitoring EEG and ERP attributes of heroin addicts from early stages of withdrawal until long-term abstinence to control the confounding effects, such as nicotine abuse and other comorbid and premorbid conditions.

Matched MeSH terms: Evoked Potentials/physiology
Localized N20 Component of Somatosensory Evoked Magnetic Fields in Frontoparietal Brain Tumor Patients Using Noise-Normalized Approaches

Elaina NS, Malik AS, Shams WK, Badruddin N, Abdullah JM, Reza MF

Clin Neuroradiol, 2018 Jun;28(2):267-281.
PMID: 28116447 DOI: 10.1007/s00062-017-0557-0

PURPOSE: To localize sensorimotor cortical activation in 10 patients with frontoparietal tumors using quantitative magnetoencephalography (MEG) with noise-normalized approaches.
MATERIAL AND METHODS: Somatosensory evoked magnetic fields (SEFs) were elicited in 10 patients with somatosensory tumors and in 10 control participants using electrical stimulation of the median nerve via the right and left wrists. We localized the N20m component of the SEFs using dynamic statistical parametric mapping (dSPM) and standardized low-resolution brain electromagnetic tomography (sLORETA) combined with 3D magnetic resonance imaging (MRI). The obtained coordinates were compared between groups. Finally, we statistically evaluated the N20m parameters across hemispheres using non-parametric statistical tests.
RESULTS: The N20m sources were accurately localized to Brodmann area 3b in all members of the control group and in seven of the patients; however, the sources were shifted in three patients relative to locations outside the primary somatosensory cortex (SI). Compared with the affected (tumor) hemispheres in the patient group, N20m amplitudes and the strengths of the current sources were significantly lower in the unaffected hemispheres and in both hemispheres of the control group. These results were consistent for both dSPM and sLORETA approaches.
CONCLUSION: Tumors in the sensorimotor cortex lead to cortical functional reorganization and an increase in N20m amplitude and current-source strengths. Noise-normalized approaches for MEG analysis that are integrated with MRI show accurate and reliable localization of sensorimotor function.

Matched MeSH terms: Evoked Potentials, Somatosensory*
Study of target and non-target interplay in spatial attention task

Sweeti, Joshi D, Panigrahi BK, Anand S, Santhosh J

J Med Eng Technol, 2018 Feb;42(2):113-120.
PMID: 29448856 DOI: 10.1080/03091902.2018.1433244

Selective visual attention is the ability to selectively pay attention to the targets while inhibiting the distractors. This paper aims to study the targets and non-targets interplay in spatial attention task while subject attends to the target object present in one visual hemifield and ignores the distractor present in another visual hemifield. This paper performs the averaged evoked response potential (ERP) analysis and time-frequency analysis. ERP analysis agrees to the left hemisphere superiority over late potentials for the targets present in right visual hemifield. Time-frequency analysis performed suggests two parameters i.e. event-related spectral perturbation (ERSP) and inter-trial coherence (ITC). These parameters show the same properties for the target present in either of the visual hemifields but show the difference while comparing the activity corresponding to the targets and non-targets. In this way, this study helps to visualise the difference between targets present in the left and right visual hemifields and, also the targets and non-targets present in the left and right visual hemifields. These results could be utilised to monitor subjects' performance in brain-computer interface (BCI) and neurorehabilitation.

Matched MeSH terms: Evoked Potentials/physiology*

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