Displaying publications 41 - 54 of 54 in total

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  1. A rapid event-related potential (ERP) method for point-of-care evaluation of brain function: development of the Halifax Consciousness Scanner
    Sculthorpe-Petley L, Liu C, Hajra SG, Parvar H, Satel J, Trappenberg TP, et al.
    J Neurosci Methods, 2015 Apr 30;245:64-72.
    PMID: 25701685 DOI: 10.1016/j.jneumeth.2015.02.008
    Event-related potentials (ERPs) may provide a non-invasive index of brain function for a range of clinical applications. However, as a lab-based technique, ERPs are limited by technical challenges that prevent full integration into clinical settings.
    Matched MeSH terms: Acoustic Stimulation
  2. Role of impacted cerumen in hearing loss
    Subha ST, Raman R
    Ear Nose Throat J, 2006 Oct;85(10):650, 652-3.
    PMID: 17124935
    We performed a study to determine if cerumen in the ear canal causes significant hearing loss and to ascertain if there is any correlation between the amount of cerumen and the degree of hearing loss. Our study was conducted on 109 ears in 80 patients. The results indicated that impacted cerumen does cause a significant degree of conductive hearing loss. We found no significant correlation between the length of the cerumen plug and the severity of hearing loss. Nor did we find any significant correlation between the presence of impacted cerumen and variables such as age, sex, ethnicity, or affected side.
    Matched MeSH terms: Acoustic Stimulation
  3. The effect of intensity on pitch in electric hearing and its relationship to the speech perception performance of cochlear implantees
    Umat C, McDermott HJ, McKay CM
    J Am Acad Audiol, 2006 12 13;17(10):733-46.
    PMID: 17153721
    This study investigated the effect of intensity on pitch in electric hearing and its relationship to the speech perception ability of cochlear implantees. Subjects were 13 adult users of the Nucleus 22 cochlear implant system, using either the Spectra22 or ESPrit22 speech processor and the SPEAK speech processing strategy. A multidimensional scaling technique was employed. Speech perception was measured using sentences and vowels. All measurements were performed in a soundfield condition, and subjects wore their own speech processors with their normally used settings. Results showed a significant correlation between the degree of deviation of the subjects' stimulus spaces from the "ideal" space and subjects' performance with the sentences, but not with the vowels. A significant correlation was found between subjects' response variability in performing the multidimensional scaling task and their speech perception measures, suggesting that spectral smearing or underlying cognitive abilities might affect implantees' speech perception performance.
    Matched MeSH terms: Acoustic Stimulation
  4. Latah: an Indonesian startle syndrome
    Bakker MJ, van Dijk JG, Pramono A, Sutarni S, Tijssen MA
    Mov Disord, 2013 Mar;28(3):370-9.
    PMID: 23283702 DOI: 10.1002/mds.25280
    The nature of culture-specific startles syndromes such as "Latah" in Indonesia and Malaysia is ill understood. Hypotheses concerning their origin include sociocultural behavior, psychiatric disorders, and neurological syndromes. The various disorders show striking similarities despite occurring in diverse cultural settings and genetically distant populations. They are characterized clinically by exaggerated startle responses and involuntary vocalizations, echolalia, and echopraxia. Quantifying startle reflexes may help define Latah within the 3 groups of startle syndromes: (1) hyperekplexia, (2) startle-induced disorders, and (3) neuropsychiatric startle syndromes. Twelve female Latah patients (mean age, 44.6 years; SD, 7.7 years) and 12 age-, sex- and socioeconomically matched controls (mean age, 42.3 year; SD, 8.0) were studied using structured history taking and neurological examination including provocation of vocalizations, echolalia, and echopraxia. We quantified auditory startle reflexes with electromyographic activity of 6 left-sided muscles following 104-dB tones. We defined 2 phases for the startle response: a short latency motor startle reflex initiated in the lower brain stem <100/120 ms) and a later, second phase more influenced by psychological factors (the "orienting reflex," 100/120-1000 ms after the stimulus). Early as well as late motor startle responses were significantly increased in patients compared with controls (P ≤ .05). Following their startle response, Latah patients showed stereotyped responses including vocalizations and echo phenomena. Startle responses were increased, but clinically these proved insignificant compared with the stereotyped behavioral responses following the startle response. This study supports the classification of Latah as a "neuropsychiatric startle syndrome."
    Matched MeSH terms: Acoustic Stimulation
  5. Investigation of brain electrophysiological properties among heroin addicts: Quantitative EEG and event-related potentials
    Motlagh F, Ibrahim F, Rashid R, Seghatoleslam T, Habil H
    J Neurosci Res, 2017 08;95(8):1633-1646.
    PMID: 27862172 DOI: 10.1002/jnr.23988
    This study aims to introduce a new approach of a comprehensive paradigm to evaluate brain electrophysiological properties among addicts. Electroencephalographic spectral power as well as amplitudes and latencies of mismatch negativity (MMN), P300, and P600 components were evaluated among 19 male heroin addicts and 19 healthy nonsmoker subjects using a paradigm consisting of three subparadigms, namely (1) digit span Wechsler test, (2) auditory oddball, and (3) visual cue-reactivity oddball paradigms. Task 1 provided auditory P300 and P600 in association with working memory. Task 2 provided auditory P300 as well as small and large deviant MMN event-related potential (ERPs). Finally, task 3 provided visual cue-reactivity P300. Results show that beta power was higher among heroin addicts while delta, theta, and alpha powers were decreased compared with healthy subjects. ERP analysis confirmed the decline of brain-evoked potential amplitudes when compared with healthy subjects, thus indicating a broad neurobiological vulnerability of preattentive and attentional processing including attentional deficits and compromise of discrimination abilities. The prolonged latency of ERPs reflects poor cognitive capacity in the engagement of attention and memory resources. On the other hand, an increase of attention towards the heroin-related stimuli could be concluded from the increase of P300 in the cue-reactivity condition among heroin addicts. Findings suggest that applying this paradigm in addiction studies benefits comprehensive evaluation of neuroelectrophysiological activity among addicts, which can promote a better understanding of drugs' effects on the brain as well as define new neuroelectrophysiological characteristics of addiction properties. © 2016 Wiley Periodicals, Inc.
    Matched MeSH terms: Acoustic Stimulation
  6. Development and standardization of single and double dichotic digit tests in the Malay language
    Mukari SZ, Keith RW, Tharpe AM, Johnson CD
    Int J Audiol, 2006 Jun;45(6):344-52.
    PMID: 16777781 DOI: 10.1080/14992020600582174
    Single and double dichotic digit tests in Malay language were developed and standardized as an initial attempt to incorporate tests of auditory processing within the scope of audiology practice in Malaysia. Normative data under free recall, directed right-ear first, and directed left-ear first listening conditions were determined using 120 Malay children between the ages of 6 and 11 years old with normal hearing and normal academic performance. Test-retest reliability was assessed in 15 of the study subjects. In general, the double dichotic digit test produced greater differences in scores between age groups, and a greater right-ear advantage than the single dichotic digit test. In addition, the double dichotic digit test also had higher test-retest reliability. These findings suggest the double dichotic digit test is more clinically applicable.
    Matched MeSH terms: Acoustic Stimulation
  7. Reliability and Accuracy of Chirp Based Multiple Auditory Steady State Response (MSSR) and Auditory Brainstem Response (ABR) in Children
    Woei TJ, Mazlan R, Tamil AM, Rosli NSM, Hasbi SM, Hashim ND, et al.
    Int Tinnitus J, 2023 Dec 04;27(1):75-81.
    PMID: 38050889 DOI: 10.5935/0946-5448.20230013
    OBJECTIVE: The purpose of this study was to compare the reliability and accuracy of chirp-based Multiple Auditory Steady State Response (MSSR) and Auditory Brainstem Response (ABR) in children.

    METHODS: The prospective clinical study was conducted at Selayang Hospital (SH) and Hospital Canselor Tuanku Muhriz (HCTM) within one year. A total of 38 children ranging from 3 to 18 years old underwent hearing evaluation using ABR tests and MSSR under sedation. The duration of both tests were then compared.

    RESULTS: The estimated hearing threshold of frequency specific chirp MSSR showed good correlation with ABR especially in higher frequencies such as 2000 Hz and 4000Hz with the value of cronbach alpha of 0.890, 0.933, 0.970 and 0.969 on 500Hz, 1000Hz, 2000Hz and 4000Hz. The sensitivity of MSSR is 0.786, 0.75, 0.957 and 0.889 and specificity is 0.85, 0.882, 0.979 and 0.966 over 500Hz, 1000Hz, 2000Hz and 4000Hz. The duration of MSSR tests were shorter than ABR tests in normal hearing children with an average of 35.3 minutes for MSSR tests and 46.4 minutes for ABR tests. This can also be seen in children with hearing loss where the average duration for MSSR tests is 40.0 minutes and 52.0 minutes for ABR tests.

    CONCLUSION: MSSR showed good correlation and reliability in comparison with ABR especially on higher frequencies. Hence, MSSR is a good clinical test to diagnose children with hearing loss.

    Matched MeSH terms: Acoustic Stimulation
  8. Fulltext The effects of age on the strategic use of pitch accents in memory for discourse: a processing-resource account
    Fraundorf SH, Watson DG, Benjamin AS
    Psychol Aging, 2012 Mar;27(1):88-98.
    PMID: 21639646 DOI: 10.1037/a0024138
    In two experiments, we investigated age-related changes in how prosodic pitch accents affect memory. Participants listened to recorded discourses that contained two contrasts between pairs of items (e.g., one story contrasted British scientists with French scientists and Malaysia with Indonesia). The end of each discourse referred to one item from each pair; these references received a pitch accent that either denoted contrast (L + H* in the ToBI system) or did not (H*). A contrastive accent on a particular pair improved later recognition memory equally for young and older adults. However, older adults showed decreased memory if the other pair received a contrastive accent (Experiment 1). Young adults with low working memory performance also showed this penalty (Experiment 2). These results suggest that pitch accents guide processing resources to important information for both older and younger adults but diminish memory for less important information in groups with reduced resources, including older adults.
    Matched MeSH terms: Acoustic Stimulation
  9. Fulltext A Novel Approach for Classifying Native Chinese and Malay Speaking Persons According to Cortical Auditory Evoked Responses
    Ibrahim IA, Ting HN, Moghavvemi M
    J Int Adv Otol, 2019 Apr;15(1):87-93.
    PMID: 30924771 DOI: 10.5152/iao.2019.4553
    OBJECTIVES: This study uses a new approach for classifying the human ethnicity according to the auditory brain responses (electroencephalography [EEG] signals) with a high level of accuracy. Moreover, the study presents three different algorithms used to classify the human ethnicity using auditory brain responses. The algorithms were tested on Malays and Chinese as a case study.

    MATERIALS AND METHODS: The EEG signal was used as a brain response signal, which was evoked by two auditory stimuli (Tones and Consonant Vowels stimulus). The study was carried out on Malaysians (Malay and Chinese) with normal hearing and with hearing loss. A ranking process for the subjects' EEG data and the nonlinear features was used to obtain the maximum classification accuracy.

    RESULTS: The study formulated the classification of Normal Hearing Ethnicity Index and Sensorineural Hearing Loss Ethnicity Index. These indices classified the human ethnicity according to brain auditory responses by using numerical values of response signal features. Three classification algorithms were used to verify the human ethnicity. Support Vector Machine (SVM) classified the human ethnicity with an accuracy of 90% in the cases of normal hearing and sensorineural hearing loss (SNHL); the SVM classified with an accuracy of 84%.

    CONCLUSION: The classification indices categorized or separated the human ethnicity in both hearing cases of normal hearing and SNHL with high accuracy. The SVM classifier provided a good accuracy in the classification of the auditory brain responses. The proposed indices might constitute valuable tools for the classification of the brain responses according to the human ethnicity.

    Matched MeSH terms: Acoustic Stimulation/methods
  10. Emotion classification in Parkinson's disease by higher-order spectra and power spectrum features using EEG signals: a comparative study
    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: Acoustic Stimulation
  11. Fulltext Gap-induced inhibition of the post-auricular muscle response in humans and guinea pigs
    Wilson CA, Berger JI, de Boer J, Sereda M, Palmer AR, Hall DA, et al.
    Hear Res, 2019 03 15;374:13-23.
    PMID: 30685571 DOI: 10.1016/j.heares.2019.01.009
    A common method for measuring changes in temporal processing sensitivity in both humans and animals makes use of GaP-induced Inhibition of the Acoustic Startle (GPIAS). It is also the basis of a common method for detecting tinnitus in rodents. However, the link to tinnitus has not been properly established because GPIAS has not yet been used to objectively demonstrate tinnitus in humans. In guinea pigs, the Preyer (ear flick) myogenic reflex is an established method for measuring the acoustic startle for the GPIAS test, while in humans, it is the eye-blink reflex. Yet, humans have a vestigial remnant of the Preyer reflex, which can be detected by measuring skin surface potentials associated with the Post-Auricular Muscle Response (PAMR). A similar electrical potential can be measured in guinea pigs and we aimed to show that the PAMR could be used to demonstrate GPIAS in both species. In guinea pigs, we compare the GPIAS measured using the pinna movement of the Preyer reflex and the electrical potential of the PAMR to demonstrate that the two are at least equivalent. In humans, we establish for the first time that the PAMR provides a reliable way of measuring GPIAS that is a pure acoustic alternative to the multimodal eye-blink reflex. Further exploratory tests showed that while eye gaze position influenced the size of the PAMR response, it did not change the degree of GPIAS. Our findings confirm that the PAMR is a sensitive method for measuring GPIAS and suggest that it may allow direct comparison of temporal processing between humans and animals and may provide a basis for an objective test of tinnitus.
    Matched MeSH terms: Acoustic Stimulation
  12. Fulltext The heterospecific calling song can improve conspecific signal detection in a bushcricket species
    Abdelatti ZAS, Hartbauer M
    Hear Res, 2017 11;355:70-80.
    PMID: 28974384 DOI: 10.1016/j.heares.2017.09.011
    In forest clearings of the Malaysian rainforest, chirping and trilling Mecopoda species often live in sympatry. We investigated whether a phenomenon known as stochastic resonance (SR) improved the ability of individuals to detect a low-frequent signal component typical of chirps when members of the heterospecific trilling species were simultaneously active. This phenomenon may explain the fact that the chirping species upholds entrainment to the conspecific song in the presence of the trill. Therefore, we evaluated the response probability of an ascending auditory neuron (TN-1) in individuals of the chirping Mecopoda species to triple-pulsed 2, 8 and 20 kHz signals that were broadcast 1 dB below the hearing threshold while increasing the intensity of either white noise or a typical triller song. Our results demonstrate the existence of SR over a rather broad range of signal-to-noise ratios (SNRs) of input signals when periodic 2 kHz and 20 kHz signals were presented at the same time as white noise. Using the chirp-specific 2 kHz signal as a stimulus, the maximum TN-1 response probability frequently exceeded the 50% threshold if the trill was broadcast simultaneously. Playback of an 8 kHz signal, a common frequency band component of the trill, yielded a similar result. Nevertheless, using the trill as a masker, the signal-related TN-1 spiking probability was rather variable. The variability on an individual level resulted from correlations between the phase relationship of the signal and syllables of the trill. For the first time, these results demonstrate the existence of SR in acoustically-communicating insects and suggest that the calling song of heterospecifics may facilitate the detection of a subthreshold signal component in certain situations. The results of the simulation of sound propagation in a computer model suggest a wide range of sender-receiver distances in which the triller can help to improve the detection of subthreshold signals in the chirping species.
    Matched MeSH terms: Acoustic Stimulation
  13. Dexamphetamine increased speech and visual unimodal illusions in healthy participants without affecting temporal binding window
    Voon FL, Loffman SJ, Lim MJH, Lee JWY, Iyyalol R, Martin-Iverson MT
    Hum Psychopharmacol, 2024 May;39(3):e2896.
    PMID: 38353526 DOI: 10.1002/hup.2896
    OBJECTIVE: Stimuli received beyond a very short timeframe, known as temporal binding windows (TBWs), are perceived as separate events. In previous audio-visual multisensory integration (McGurk effect) studies, widening of TBWs has been observed in people with schizophrenia. The present study aimed to determine if dexamphetamine could increase TBWs in unimodal auditory and unimodal visual illusions that may have some validity as experimental models for auditory and visual hallucinations in psychotic disorders.

    METHODS: A double-blind, placebo-controlled, counter-balanced crossover design with permuted block randomisation for drug order was followed. Dexamphetamine (0.45 mg/kg, PO, q.d.) was administered to healthy participants. Phantom word illusion (speech illusion) and visual-induced flash illusion/VIFI (visual illusion) tests were measured to determine if TBWs were altered as a function of delay between stimuli presentations. Word emotional content for phantom word illusions was also analysed.

    RESULTS: Dexamphetamine significantly increased the total number of phantom words/speech illusions (p 

    Matched MeSH terms: Acoustic Stimulation
  14. Evaluation of real-world preferences and performance of hearing aids fitted according to the NAL-NL1 and DSL v5 procedures in children with moderately severe to profound hearing loss
    Quar TK, Ching TY, Newall P, Sharma M
    Int J Audiol, 2013 May;52(5):322-32.
    PMID: 23570290 DOI: 10.3109/14992027.2012.755740
    The study aims to compare the performance of hearing aids fitted according to the NAL-NL1 and DSL v5 prescriptive procedure for children.
    Matched MeSH terms: Acoustic Stimulation
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