Displaying publications 61 - 80 of 108 in total

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  1. Motlagh F, Ibrahim F, Rashid R, Shafiabady N, Seghatoleslam T, Habil H
    Psychopharmacology (Berl), 2018 Nov;235(11):3273-3288.
    PMID: 30310960 DOI: 10.1007/s00213-018-5035-0
    Methadone as the most prevalent opioid substitution medication has been shown to influence the neurophysiological functions among heroin addicts. However, there is no firm conclusion on acute neuroelectrophysiological changes among methadone-treated subjects as well as the effectiveness of methadone in restoring brain electrical abnormalities among heroin addicts. This study aims to investigate the acute and short-term effects of methadone administration on the brain's electrophysiological properties before and after daily methadone intake over 10 weeks of treatment among heroin addicts. EEG spectral analysis and single-trial event-related potential (ERP) measurements were used to investigate possible alterations in the brain's electrical activities, as well as the cognitive attributes associated with MMN and P3. The results confirmed abnormal brain activities predominantly in the beta band and diminished information processing ability including lower amplitude and prolonged latency of cognitive responses among heroin addicts compared to healthy controls. In addition, the alteration of EEG activities in the frontal and central regions was found to be associated with the withdrawal symptoms of drug users. Certain brain regions were found to be influenced significantly by methadone intake; acute effects of methadone induction appeared to be associative to its dosage. The findings suggest that methadone administration affects cognitive performance and activates the cortical neuronal networks, resulting in cognitive responses enhancement which may be influential in reorganizing cognitive dysfunctions among heroin addicts. This study also supports the notion that the brain's oscillation powers and ERPs can be utilized as neurophysiological indices for assessing the addiction treatment traits.
    Matched MeSH terms: Evoked Potentials, Auditory/drug effects*; Evoked Potentials, Auditory/physiology
  2. Dzulkarnain AA, Che Azid N
    Med J Malaysia, 2014 Aug;69(4):156-61.
    PMID: 25500842 MyJurnal
    AIM OF STUDY: This study investigated the consistency in Auditory Brainstem Response (ABR) waveform evaluations between two audiologists (inter-audiologist agreement) and within each of the audiologist (intra-audiologist agreement).
    METHODS: Two audiologists from one of the audiology clinics in Kuantan, Pahang, Malaysia were involved in this study. Both audiologists were required to identify and mark the presence of Waves I, III and V in 66 ABR waveforms. Over a one-month interval, each audiologist was required to carry out the same procedure on the same ABR waveforms. This process was continued until we had three separate reviews from each audiologist.
    RESULTS: There was a high inter-audiologist ABR waveform identification agreement (over the range 81.71-89.77%), but a lower intra-audiologist ABR waveform identification agreement (over the range 50%-78%) for both audiologists. Our results also showed a high intra-audiologist ABR latency agreement within 0.2 ms (>90%), but a slightly lower inter-audiologist latency agreement (75-84%) within 0.2 ms.
    CONCLUSION: Our results support the need for the clinic to implement further strategies for improving the respective lower agreements and consistencies. These include conducting a continuous education program and using an objective algorithm to support their interpretations.

    Study site:; International Islamic University, Malaysia (IIUM) Hearing
    and Speech Clinic
    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem
  3. Mushtaq F, Wilkie RM, Mon-Williams MA, Schaefer A
    Neuroimage, 2016 Jan 15;125:868-879.
    PMID: 26497268 DOI: 10.1016/j.neuroimage.2015.10.046
    Substantial evidence indicates that decision outcomes are typically evaluated relative to expectations learned from relatively long sequences of previous outcomes. This mechanism is thought to play a key role in general learning and adaptation processes but relatively little is known about the determinants of outcome evaluation when the capacity to learn from series of prior events is difficult or impossible. To investigate this issue, we examined how the feedback-related negativity (FRN) is modulated by information briefly presented before outcome evaluation. The FRN is a brain potential time-locked to the delivery of decision feedback and it is widely thought to be sensitive to prior expectations. We conducted a multi-trial gambling task in which outcomes at each trial were fully randomised to minimise the capacity to learn from long sequences of prior outcomes. Event-related potentials for outcomes (Win/Loss) in the current trial (Outcomet) were separated according to the type of outcomes that occurred in the preceding two trials (Outcomet-1 and Outcomet-2). We found that FRN voltage was more positive during the processing of win feedback when it was preceded by wins at Outcomet-1 compared to win feedback preceded by losses at Outcomet-1. However, no influence of preceding outcomes was found on FRN activity relative to the processing of loss feedback. We also found no effects of Outcomet-2 on FRN amplitude relative to current feedback. Additional analyses indicated that this effect was largest for trials in which participants selected a decision different to the gamble chosen in the previous trial. These findings are inconsistent with models that solely relate the FRN to prediction error computation. Instead, our results suggest that if stable predictions about future events are weak or non-existent, then outcome processing can be determined by affective systems. More specifically, our results indicate that the FRN is likely to reflect the activity of positive affective systems in these contexts. Importantly, our findings indicate that a multifactorial explanation of the nature of the FRN is necessary and such an account must incorporate affective and motivational factors in outcome processing.
    Matched MeSH terms: Evoked Potentials
  4. Zakaria MN, Jalaei B, Aw CL, Sidek D
    Neurol Sci, 2016 Jun;37(6):943-8.
    PMID: 26921173 DOI: 10.1007/s10072-016-2522-0
    Due to its objective nature, auditory brainstem response (ABR) evoked by complex stimuli has been gaining attention lately. The present study aimed to compare the speech-evoked auditory brainstem response (speech-ABR) results between two ethnic groups: Malay and Chinese. In addition, it was also of interest to compare the speech-ABR outcomes obtained from the present study with the published Caucasian data. Thirty healthy male adults (15 Malay and 15 Chinese) were enrolled in this comparative study. Speech syllable/da/presented at 80 dBnHL was used to record speech-ABR waveforms from the right ear of each subject. Amplitudes and latencies of speech-ABR peaks (V, A, C, D, E, F and O), as well as composite onset measures (V/A duration, V/A amplitude and V/A slope) were computed and analyzed. When the two ethnic groups were compared, all speech-ABR results were not statistically different from each other (p > 0.05). When the data from the present study were compared with the published Caucasian data, most of the statistical analyses were significant (p 
    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem
  5. Billings CJ, Grush LD, Maamor N
    Physiol Rep, 2017 Nov;5(20).
    PMID: 29051305 DOI: 10.14814/phy2.13464
    The effects of background noise on speech-evoked cortical auditory evoked potentials (CAEPs) can provide insight into the physiology of the auditory system. The purpose of this study was to determine background noise effects on neural coding of different phonemes within a syllable. CAEPs were recorded from 15 young normal-hearing adults in response to speech signals /s/, /ɑ/, and /sɑ/. Signals were presented at varying signal-to-noise ratios (SNRs). The effects of SNR and context (in isolation or within syllable) were analyzed for both phonemes. For all three stimuli, latencies generally decreased and amplitudes generally increased as SNR improved, and context effects were not present; however, the amplitude of the /ɑ/ response was the exception, showing no SNR effect and a significant context effect. Differential coding of /s/ and /ɑ/ likely result from level and timing differences. Neural refractoriness may result in the lack of a robust SNR effect on amplitude in the syllable context. The stable amplitude across SNRs in response to the vowel in /sɑ/ suggests the combined effects of (1) acoustic characteristics of the syllable and noise at poor SNRs and (2) refractory effects resulting from phoneme timing at good SNRs. Results provide insights into the coding of multiple-onset speech syllables in varying levels of background noise and, together with behavioral measures, may help to improve our understanding of speech-perception-in-noise difficulties.
    Matched MeSH terms: Evoked Potentials, Auditory
  6. Jalaei B, Zakaria MN, Sidek D
    Iran J Otorhinolaryngol, 2017 Jan;29(90):53-57.
    PMID: 28229064
    INTRODUCTION: Noonan syndrome (NS) is a heterogeneous genetic disease that affects many parts of the body. It was named after Dr. Jacqueline Anne Noonan, a paediatric cardiologist.

    CASE REPORT: We report audiological tests and auditory brainstem response (ABR) findings in a 5-year old Malay boy with NS. Despite showing the marked signs of NS, the child could only produce a few meaningful words. Audiological tests found him to have bilateral mild conductive hearing loss at low frequencies. In ABR testing, despite having good waveform morphology, the results were atypical. Absolute latency of wave V was normal but interpeak latencies of wave's I-V, I-II, II-III were prolonged. Interestingly, interpeak latency of waves III-V was abnormally shorter.

    CONCLUSION: Abnormal ABR results are possibly due to abnormal anatomical condition of brainstem and might contribute to speech delay.

    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem
  7. Begum, T., Reza, F., Abdullah, J.M.
    ASM Science Journal, 2011;5(2):115-121.
    MyJurnal
    Reflex epilepsy is usually induced by external stimulation, photosensitive epilepsy being the most common. Epilepsy induced by auditory stimulation is rarely studied. There are no currently published magnetoencephalographic (MEG) studies demonstrating the initiation of epileptic neuronal discharges by repeated auditory stimulations in temporal lobe epilepsy (TLE) patients. We retrospectively studied one TLE patient who underwent a MEG study to localize her epileptic focus. Auditory, somatosensory, visual and motor evoked potential studies were performed during the MEG recording. A single dipole method calculated equivalent current dipoles to localize the epileptic source. The least-squares minimization method was used to obtain the optimal solution with goodness-of-fit of greater than 80%. Periodic lateralized epileptiform discharges (PLEDs) were recorded in the temporal region when repeated auditory stimulations were done. We postulated that neuronal cortical suppression occurred during repeated stimulations which provoked epileptiform discharges (PLEDs) without any physical symptoms or aura. It was concluded that repeated stimulations could facilitate epileptiform discharges in focal area/areas in certain subjects.
    Matched MeSH terms: Evoked Potentials, Motor
  8. Abdul Rauf A. Bakar, Jayasree Santhosh, Mohammed G. Al-zidi, Ibrahim Amer Ibrahim, Ng SC, Hua NT
    Sains Malaysiana, 2017;46:2477-2488.
    The deficiency in the human auditory system of individuals suffering from sensorineural hearing loss (SNHL) is known to be associated with the difficulty in detecting of various speech phonological features that are frequently related to speech perception. This study investigated the effects of speech articulation features on the amplitude and latency of cortical auditory evoked potential (CAEP) components. The speech articulation features included the placing contrast and voicing contrast. 12 Malay subjects with normal hearing and 12 Malay subjects with SNHL were recruited for the study. The CAEPs response recorded at higher amplitude with longer latency when stimulated by voicing contrast cues compared to that of the placing contrast. Subjects with SNHL elicited greater amplitude with prolonged latencies in the majority of the CAEP components in both speech stimuli. The existence of different frequency spectral and time-varying acoustic cues of the speech stimuli was reflected by the CAEPs response strength and timing. We anticipate that the CAEPs responses could equip audiologist and clinicians with useful knowledge, concerning the potential deprivation experience by hearing impaired individuals, in auditory passive perception. This would help to determine what type of speech stimuli that might be useful in measuring speech perception abilities, especially in Malay Malaysian ethic group, for choosing a better rehabilitation program, since no such study conducted for evaluating speech perception among Malaysian clinical population.
    Matched MeSH terms: Evoked Potentials, Auditory
  9. Cheng KS, Chang YF, Han RPS, Lee PF
    PeerJ, 2017;5:e3857.
    PMID: 29018605 DOI: 10.7717/peerj.3857
    OBJECTIVES: Practitioners of mindfulness are reported to have greater cognitive control especially in conflict monitoring, response inhibition and sustained attention. However, due to the various existing methods in each mindfulness practices and also, the high commitment factor, a barrier still exists for an individual to pick up the practices. Therefore, the effect of short duration deep breathing on the cognitive control is investigated here.

    METHODS: Short duration guided deep breathing videos consisting of 5, 7 and 9 min respectively were created and used on subjects training. The effect on cognitive control was assessed using a Go/NoGo task along with event-related potential (ERP) measurements at Fz, Cz, and Pz.

    RESULTS: From the study, the significant outcome showed at the follow-up session in which participants engaged for 5 min deep breathing group showed a profound NoGo N2 amplitude increment as compared to the control group, indicating an enhanced conflict monitoring ability. An inverse relationship between the NoGo N2 amplitude and the breathing duration is observed as well at the follow-up session.

    CONCLUSION: These results indicated the possibility of performing short duration deep breathing guided by a video to achieve an enhanced conflict monitoring as an alternative to other mindfulness practices and 5 min is found to be the optimum practice duration.

    SIGNIFICANT: This study is the first to establish a relationship between deep breathing and conflict monitoring through ERP. The study population of young adults taken from the same environment reduces the variance in ERP results due to age and environment.

    LIMITATION: A larger sample size would provide a greater statistical power. A longer duration of deep breathing should be investigated to further clarify the relationship between the practice duration and the NoGo N2 amplitude. The result can be split by gender and analyzed separately due to the different brain structure of males and females.

    Matched MeSH terms: Evoked Potentials
  10. Fiedler P, Pedrosa P, Griebel S, Fonseca C, Vaz F, Supriyanto E, et al.
    Brain Topogr, 2015 Sep;28(5):647-656.
    PMID: 25998854 DOI: 10.1007/s10548-015-0435-5
    Current usage of electroencephalography (EEG) is limited to laboratory environments. Self-application of a multichannel wet EEG caps is practically impossible, since the application of state-of-the-art wet EEG sensors requires trained laboratory staff. We propose a novel EEG cap system with multipin dry electrodes overcoming this problem. We describe the design of a novel 24-pin dry electrode made from polyurethane and coated with Ag/AgCl. A textile cap system holds 97 of these dry electrodes. An EEG study with 20 volunteers compares the 97-channel dry EEG cap with a conventional 128-channel wet EEG cap for resting state EEG, alpha activity, eye blink artifacts and checkerboard pattern reversal visual evoked potentials. All volunteers report a good cap fit and good wearing comfort. Average impedances are below 150 kΩ for 92 out of 97 dry electrodes, enabling recording with standard EEG amplifiers. No significant differences are observed between wet and dry power spectral densities for all EEG bands. No significant differences are observed between the wet and dry global field power time courses of visual evoked potentials. The 2D interpolated topographic maps show significant differences of 3.52 and 0.44% of the map areas for the N75 and N145 VEP components, respectively. For the P100 component, no significant differences are observed. Dry multipin electrodes integrated in a textile EEG cap overcome the principle limitations of wet electrodes, allow rapid application of EEG multichannel caps by non-trained persons, and thus enable new fields of application for multichannel EEG acquisition.
    Matched MeSH terms: Evoked Potentials
  11. Nandrajog P, Idris Z, Azlen WN, Liyana A, Abdullah JM
    Asian J Neurosurg, 2017 Jul-Sep;12(3):447-453.
    PMID: 28761523 DOI: 10.4103/1793-5482.180921
    BACKGROUND: The aim of the study is to compare the amplitude and latency of the P300 event-related potential (ERP) component between a control group and patients after mild traumatic brain injury (mTBI) during 1-7 days (short duration) and 2-3 months (long duration), and to compare the outcome of neuropsychological tests between the long duration postinjury and control study groups.

    MATERIALS AND METHODS: We studied responses to auditory stimulation in two main and one subgroups, namely the control healthy group (19 patients, both ERP and neuropsychology test done), the mTBI 1 group (17 patients, only ERP done within 7 days after injury), and the mTBI 2 subgroup (the 17 mTBI 1 patients in whom a repeated ERP together with neuropsychological testing was done at 2-3 months postinjury). Auditory evoked responses were studied with two different stimuli (standard and target stimuli), where the P300 amplitude and latency were recorded from three midline sites and results were compared between the groups, as were the neuropsychological test results.

    RESULTS: There was a significant prolongation of the target P300 latency values shown by the MBI 1 group measured at the central electrode when compared to the control group, which was also seen when the mTBI 1 and mTBI 2 groups were compared. The results of the P300 amplitude values measured at the frontal electrode showed the control group to have higher readings during the presentation of standard tones when compared to the mTBI 1 group. The mTBI 2 group performed better on some neuropsychological tests.

    CONCLUSION: The latency of P300 was significantly prolonged in early mTBI patients who improved over time, and the neuropsychological testing on mTBI 2 patients showed them to be comparable to the control group. The study indicates that ERP should be used as an additional modality of investigation in mTBI patients.
    Matched MeSH terms: Evoked Potentials, Auditory
  12. Asma A, Abdul Fatah AW, Hamzaini AH, Mazita A
    Indian J Otolaryngol Head Neck Surg, 2013 Dec;65(Suppl 3):526-31.
    PMID: 24427708 DOI: 10.1007/s12070-011-0438-9
    In managing patient with congenital congenital aural atresia (CAA), preoperative high resolution computed tomography (HRCT) scan and hearing assessment are important. A grading system based on HRCT findings was first introduced by Jahrsdoefer in order to select appropriate candidates for operation and to predict the postoperative hearing outcome in CAA patients. The score of eight and more was considered as a good prognostic factor for hearing reconstruction surgery. However previously in our center this score was not used as the criteria for surgical procedure. This study was conducted at Center A to evaluate the correlation between pre and postoperative hearing level with HRCT based on a Jahrsdoefer grading system in patients with CAA. All records and HRCT films with CAA from January 1997 until December 2007 at Center A were evaluated. The demographic data, operative records, pre and post operative hearing levels and HRCT findings were analyzed. Hearing level in this study was based on a pure tone average of air-bone gap at 500 Hz, 1 kHz and 2 kHz or hearing level obtained from auditory brainstem response eudiometry. This study was approved by Research Ethics Committee (code number, FF-197-2008). Thirty-two ears were retrospectively evaluated. The postoperative hearing level of 30 dB and less was considered as successful hearing result postoperatively. Of the six ears which underwent canalplasty, three had achieved successful hearing result. However, there was no significant correlation between preoperative hearing level (HL) with HRCT score and postoperative HL with HRCT score at 0.05 significant levels (correlation coefficient = -0.292, P = 0.105 and correlation coefficient = -0.127, P = 0.810) respectively. Hearing evaluation and HRCT temporal bone are two independent evaluations for the patients with CAA before going for hearing reconstructive surgery.
    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem
  13. Goh HT, Chan HY, Abdul-Latif L
    J Neurol Phys Ther, 2015 Jan;39(1):15-22.
    PMID: 25427033 DOI: 10.1097/NPT.0000000000000064
    Noninvasive brain stimulation, including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), have gained popularity in the stroke rehabilitation literature. Little is known about the time course and duration of effects of noninvasive brain stimulation on corticospinal excitability in individuals with stroke. We examined the aftereffects of a single session of high-frequency rTMS (5 Hz) and anodal tDCS on corticospinal excitability in the same sample of participants with chronic stroke.
    Matched MeSH terms: Evoked Potentials, Motor/physiology
  14. Yuvaraj R, Murugappan M, Ibrahim NM, Omar MI, Sundaraj K, Mohamad K, et al.
    J Integr Neurosci, 2014 Mar;13(1):89-120.
    PMID: 24738541 DOI: 10.1142/S021963521450006X
    Deficits in the ability to process emotions characterize several neuropsychiatric disorders and are traits of Parkinson's disease (PD), and there is need for a method of quantifying emotion, which is currently performed by clinical diagnosis. Electroencephalogram (EEG) signals, being an activity of central nervous system (CNS), can reflect the underlying true emotional state of a person. This study applied machine-learning algorithms to categorize EEG emotional states in PD patients that would classify six basic emotions (happiness and sadness, fear, anger, surprise and disgust) in comparison with healthy controls (HC). Emotional EEG data were recorded from 20 PD patients and 20 healthy age-, education level- and sex-matched controls using multimodal (audio-visual) stimuli. The use of nonlinear features motivated by the higher-order spectra (HOS) has been reported to be a promising approach to classify the emotional states. In this work, we made the comparative study of the performance of k-nearest neighbor (kNN) and support vector machine (SVM) classifiers using the features derived from HOS and from the power spectrum. Analysis of variance (ANOVA) showed that power spectrum and HOS based features were statistically significant among the six emotional states (p < 0.0001). Classification results shows that using the selected HOS based features instead of power spectrum based features provided comparatively better accuracy for all the six classes with an overall accuracy of 70.10% ± 2.83% and 77.29% ± 1.73% for PD patients and HC in beta (13-30 Hz) band using SVM classifier. Besides, PD patients achieved less accuracy in the processing of negative emotions (sadness, fear, anger and disgust) than in processing of positive emotions (happiness, surprise) compared with HC. These results demonstrate the effectiveness of applying machine learning techniques to the classification of emotional states in PD patients in a user independent manner using EEG signals. The accuracy of the system can be improved by investigating the other HOS based features. This study might lead to a practical system for noninvasive assessment of the emotional impairments associated with neurological disorders.
    Matched MeSH terms: Evoked Potentials/physiology*
  15. Salina H, Abdullah A, Mukari SZ, Azmi MT
    Eur Arch Otorhinolaryngol, 2010 Apr;267(4):495-9.
    PMID: 19727788 DOI: 10.1007/s00405-009-1080-y
    Transient-evoked otoacoustic emission (TEOAE) is a well-established screening tool for universal newborn hearing screening. The aims of this study are to measure the effects of background noise on recording of TEOAE and the duration required to complete the test at various noise levels. This study is a prospective study from June 2006 until May 2007. The study population were newborns from postnatal wards who were delivered at term pregnancy. Newborns who were more than 8-h old and passed a hearing screening testing using screening auditory brainstem response (SABRe) were further tested with TEOAE in four different test environments [isolation room in the ward during non-peak hour (E1), isolation room in the ward during peak hour (E2), maternal bedside in the ward during non-peak hour (E3) and maternal bedside in the ward during peak hour (E4)]. This study showed that test environment significantly influenced the time required to complete testing in both ears with F [534.23] = 0.945; P < 0.001 on the right ear and F [636.54] = 0.954; P < 0.001 on the left. Our study revealed that TEOAE testing was efficient in defining the presence of normal hearing in our postnatal wards at maternal bedside during non-peak hour with a specificity of 96.8%. Our study concludes that background noise levels for acceptable and accurate TEOAE recording in newborns should not exceed 65 dB A. In addition, when using TEOAE assessment in noisy environments, the time taken to obtain accurate results will greatly increase.
    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem/physiology
  16. Huan NJ, Palaniappan R
    J Neural Eng, 2004 Sep;1(3):142-50.
    PMID: 15876633
    In this paper, we have designed a two-state brain-computer interface (BCI) using neural network (NN) classification of autoregressive (AR) features from electroencephalogram (EEG) signals extracted during mental tasks. The main purpose of the study is to use Keirn and Aunon's data to investigate the performance of different mental task combinations and different AR features for BCI design for individual subjects. In the experimental study, EEG signals from five mental tasks were recorded from four subjects. Different combinations of two mental tasks were studied for each subject. Six different feature extraction methods were used to extract the features from the EEG signals: AR coefficients computed with Burg's algorithm, AR coefficients computed with a least-squares (LS) algorithm and adaptive autoregressive (AAR) coefficients computed with a least-mean-square (LMS) algorithm. All the methods used order six applied to 125 data points and these three methods were repeated with the same data but with segmentation into five segments in increments of 25 data points. The multilayer perceptron NN trained by the back-propagation algorithm (MLP-BP) and linear discriminant analysis (LDA) were used to classify the computed features into different categories that represent the mental tasks. We compared the classification performances among the six different feature extraction methods. The results showed that sixth-order AR coefficients with the LS algorithm without segmentation gave the best performance (93.10%) using MLP-BP and (97.00%) using LDA. The results also showed that the segmentation and AAR methods are not suitable for this set of EEG signals. We conclude that, for different subjects, the best mental task combinations are different and proper selection of mental tasks and feature extraction methods are essential for the BCI design.
    Matched MeSH terms: Evoked Potentials/physiology
  17. Maamor N, Billings CJ
    Neurosci Lett, 2017 01 01;636:258-264.
    PMID: 27838448 DOI: 10.1016/j.neulet.2016.11.020
    The purpose of this study was to determine the effects of noise type, signal-to-noise ratio (SNR), age, and hearing status on cortical auditory evoked potentials (CAEPs) to speech sounds. This helps to explain the hearing-in-noise difficulties often seen in the aging and hearing impaired population. Continuous, modulated, and babble noise types were presented at varying SNRs to 30 individuals divided into three groups according to age and hearing status. Significant main effects of noise type, SNR, and group were found. Interaction effects revealed that the SNR effect varies as a function of noise type and is most systematic for continuous noise. Effects of age and hearing loss were limited to CAEP latency and were differentially modulated by energetic and informational-like masking. It is clear that the spectrotemporal characteristics of signals and noises play an important role in determining the morphology of neural responses. Participant factors such as age and hearing status, also play an important role in determining the brain's response to complex auditory stimuli and contribute to the ability to listen in noise.
    Matched MeSH terms: Evoked Potentials, Auditory/physiology*
  18. Chan YC, Punzalan-Sotelo AM, Kannan TA, Shahrizaila N, Umapathi T, Goh EJH, et al.
    Muscle Nerve, 2017 Nov;56(5):919-924.
    PMID: 28093784 DOI: 10.1002/mus.25577
    INTRODUCTION: In this study we propose electrodiagnostic criteria for early reversible conduction failure (ERCF) in axonal Guillain-Barré syndrome (GBS) and apply them to a cohort of GBS patients.

    METHODS: Serial nerve conduction studies (NCS) were retrospectively analyzed in 82 GBS patients from 3 centers. The criteria for the presence of ERCF in a nerve were: (i) a 50% increase in amplitude of distal compound muscle action potentials or sensory nerve action potentials; or (ii) resolution of proximal motor conduction block with an accompanying decrease in distal latencies or compound muscle action potential duration or increase in conduction velocities.

    RESULTS: Of 82 patients from 3 centers, 37 (45%) had ERCF, 21 (26%) had a contrasting evolution pattern, and 8 (10%) had both. Sixteen patients did not show an amplitude increase of at least 50%.

    CONCLUSION: Our proposed criteria identified a group of patients with a characteristic evolution of NCS abnormality that is consistent with ERCF. Muscle Nerve 56: 919-924, 2017.

    Matched MeSH terms: Evoked Potentials, Motor/physiology*
  19. Dzulkarnain AAA, Noor Ibrahim SHM, Anuar NFA, Abdullah SA, Tengku Zam Zam TZH, Rahmat S, et al.
    Int J Audiol, 2017 Oct;56(10):723-732.
    PMID: 28415891 DOI: 10.1080/14992027.2017.1313462
    OBJECTIVE: To investigate the influence of two different electrode montages (ipsilateral: reference to mastoid and vertical: reference to nape of neck) to the ABR results recorded using a level-specific (LS)-CE-Chirp® in normally hearing subjects at multiple intensities levels.

    DESIGN: Quasi-experimental and repeated measure study designs were applied in this study. Two different stopping criteria were used, (1) a fixed-signal averaging 4000 sweeps and, (2) a minimum quality indicator of Fmp = 3.1 with a minimum of 800 sweeps.

    STUDY SAMPLE: Twenty-nine normally hearing adults (18 females, 11 male) participated.

    RESULTS: Wave V amplitudes were significantly larger in the LS CE-Chirp® recorded from the vertical montage than the ipsilateral montage. Waves I and III amplitudes were significantly larger from the ipsilateral LS CE-Chirp® than from the other montages and stimulus combinations. The differences in the quality of the ABR recording between the vertical and ipsilateral montages were marginal.

    CONCLUSIONS: Overall, the result suggested that the vertical LS CE-Chirp® ABR had a high potential for a threshold-seeking application, because it produced a higher wave V amplitude. The Ipsilateral LS CE-Chirp® ABR, on the other hand, might also have a high potential for the site of lesion application, because it produced larger waves I and III amplitudes.

    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem*
  20. Dzulkarnain AAA, Abdullah SA, Ruzai MAM, Ibrahim SHMN, Anuar NFA, Rahim 'EA
    Am J Audiol, 2018 Sep 12;27(3):294-305.
    PMID: 30054628 DOI: 10.1044/2018_AJA-17-0087
    Purpose: The purpose of this study was to investigate the influence of 2 different electrode montages (ipsilateral and vertical) on the auditory brainstem response (ABR) findings elicited from narrow band (NB) level-specific (LS) CE-Chirp and tone-burst in subjects with normal hearing at several intensity levels and frequency combinations.

    Method: Quasi-experimental and repeated-measures study designs were used in this study. Twenty-six adults with normal hearing (17 females, 9 males) participated. ABRs were acquired from the study participants at 3 intensity levels (80, 60, and 40 dB nHL), 3 frequencies (500, 1000, and 2000 Hz), 2 electrode montages (ipsilateral and vertical), and 2 stimuli (NB LS CE-Chirp and tone-burst) using 2 stopping criteria (fixed averages at 4,000 sweeps and F test at multiple points = 3.1).

    Results: Wave V amplitudes were only 19%-26% larger for the vertical recordings than the ipsilateral recordings in both the ABRs obtained from the NB LS CE-Chirp and tone-burst stimuli. The mean differences in the F test at multiple points values and the residual noise levels between the ABRs obtained from the vertical and ipsilateral montages were statistically not significant. In addition, the ABR elicited from the NB LS CE-Chirp was significantly larger (up to 69%) than those from the tone-burst, except at the lower intensity level.

    Conclusion: Both the ipsilateral and vertical montages can be used to record ABR to the NB LS CE-Chirp because of the small enhancement in the wave V amplitude provided by the vertical montage.

    Matched MeSH terms: Evoked Potentials, Auditory, Brain Stem/physiology*
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