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Wu CC, Hamm JP, Lim VK, Kirk IJ. Musical training increases functional connectivity, but does not enhance mu suppression. Neuropsychologia 2017; 104:223-233. [PMID: 28864245 DOI: 10.1016/j.neuropsychologia.2017.08.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/13/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022]
Abstract
Musical training provides an ideal platform for investigating action representation for sound. Learning to play an instrument requires integration of sensory and motor perception-action processes. Functional neuroimaging studies have indicated that listening to trained music can result in the activity in premotor areas, even after a short period of training. These studies suggest that action representation systems are heavily dependent on specific sensorimotor experience. However, others suggest that because humans naturally move to music, sensorimotor training is not necessary and there is a more general action representation for music. We previously demonstrated that EEG mu suppression, commonly implemented to demonstrate mirror-neuron-like action representation while observing movements, can also index action representations for sounds in pianists. The current study extends these findings to a group of non-musicians who learned to play randomised sequences on a piano, in order to acquire specific sound-action mappings for the five fingers of their right hand. We investigated training-related changes in neural dynamics as indexed by mu suppression and task-related coherence measures. To test the specificity of training effects, we included sounds similar to those encountered in the training and additionally rhythm sequences. We found no effect of training on mu suppression between pre- and post-training EEG recordings. However, task-related coherence indexing functional connectivity between electrodes over audiomotor areas increased after training. These results suggest that long-term training in musicians and short-term training in novices may be associated with different stages of audiomotor integration that can be reflected in different EEG measures. Furthermore, the changes in functional connectivity were specifically found for piano tones, and were not apparent when participants listened to rhythms, indicating some degree of specificity related to training.
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Affiliation(s)
- C Carolyn Wu
- School of Psychology, The University of Auckland, Auckland, New Zealand; IRTG Adaptive Minds, School of Psychology, Saarland University, Saarbruecken, Germany.
| | - Jeff P Hamm
- School of Psychology, The University of Auckland, Auckland, New Zealand
| | - Vanessa K Lim
- School of Psychology, The University of Auckland, Auckland, New Zealand
| | - Ian J Kirk
- School of Psychology, The University of Auckland, Auckland, New Zealand
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McWhinney SR, Tremblay A, Chevalier TM, Lim VK, Newman AJ. Using CForest to Analyze Diffusion Tensor Imaging Data: A Study of White Matter Integrity in Healthy Aging. Brain Connect 2016; 6:747-758. [DOI: 10.1089/brain.2016.0451] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sean R. McWhinney
- Department of Psychology & Neuroscience, Dalhousie University, Halifax, Canada
| | - Antoine Tremblay
- Department of Psychology & Neuroscience, Dalhousie University, Halifax, Canada
- Department of Linguistics, Saint Mary's University, Halifax, Canada
- NovaScape Data Analysis and Consulting, Halifax, Canada
| | | | - Vanessa K. Lim
- School of Psychology, University of Auckland, Auckland, New Zealand
| | - Aaron J. Newman
- Department of Psychology & Neuroscience, Dalhousie University, Halifax, Canada
- Department of Psychiatry, Dalhousie University, Halifax, Canada
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Wu CC, Hamm JP, Lim VK, Kirk IJ. Mu rhythm suppression demonstrates action representation in pianists during passive listening of piano melodies. Exp Brain Res 2016; 234:2133-9. [DOI: 10.1007/s00221-016-4615-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 02/26/2016] [Indexed: 11/30/2022]
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Glyn V, Lim VK, Hamm JP, Mathur A, Hughes B. Behavioural and electrophysiological effects related to semantic violations during braille reading. Neuropsychologia 2015; 77:298-312. [PMID: 26359716 DOI: 10.1016/j.neuropsychologia.2015.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 09/04/2015] [Accepted: 09/04/2015] [Indexed: 10/23/2022]
Abstract
This study investigated the potential to detect event related potentials (ERPs) occurring in response to a specific task in braille reading. This would expand current methodologies for studying the cognitive processes underlying braille reading. An N400 effect paradigm was utilised, whereby proficient blind braille readers read congruent- and incongruent-ending braille sentences. Kinematic and electroencephalography (EEG) data were obtained simultaneously and synchronised. The ERPs differed between the incongruent and congruent sentences in a manner consistent with the N400 effect found with a previous sighted reading paradigm, demonstrating that ERPs can be obtained during braille reading. The frequency of finger reversals and the degree of intermittency in the finger velocity were significantly higher when reading incongruent versus congruent sentence endings. Both reversals and the potential N400 effect may reflect processes involved in semantic unification. These findings have significant implications for the modelling of braille reading. The refinement of the technique will enable other ERPs to be identified and related to behavioural responses, to further our understanding of the braille reading process.
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Affiliation(s)
- Vania Glyn
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Vanessa K Lim
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Jeff P Hamm
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Ashwin Mathur
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Barry Hughes
- School of Psychology, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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Jiang C, Lim VK, Wang H, Hamm JP. Difficulties with pitch discrimination influences pitch memory performance: evidence from congenital amusia. PLoS One 2013; 8:e79216. [PMID: 24205375 PMCID: PMC3808300 DOI: 10.1371/journal.pone.0079216] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Accepted: 09/27/2013] [Indexed: 11/25/2022] Open
Abstract
Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual’s threshold with a two down one up staircase procedure and using this to create conditions where two pitches (the standard and the comparison tones) differed by 1x, 2x, and 3x the threshold setting. For comparison with the literature a condition that employed a constant pitch difference of four semitones was also included. The results showed that pitch memory performance improved as the discrimination between the standard and the comparison tones was made easier for both amusic and control groups, and more importantly, that amusics did not show any pitch retention deficits when the discrimination difficulty was equated. In contrast, consistent with previous literature, amusics performed worse than controls when the physical pitch distance was held constant at four semitones. This impaired performance has been interpreted as evidence for pitch memory impairment in the past. However, employing a constant pitch distance always makes the difference closer to the discrimination threshold for the amusic group than for the control group. Therefore, reduced performance in this condition may simply reflect differences in the perceptual difficulty of the discrimination. The findings indicate the importance of equating the discrimination difficulty when investigating memory.
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Affiliation(s)
- Cunmei Jiang
- Music College, Shanghai Normal University, Shanghai, China
- * E-mail: (CJ); (JH)
| | - Vanessa K. Lim
- Cognitive Neuroscience Research Group, University of Auckland, Auckland, New Zealand
| | - Hang Wang
- Music College, Shanghai Normal University, Shanghai, China
| | - Jeff P. Hamm
- Cognitive Neuroscience Research Group, University of Auckland, Auckland, New Zealand
- * E-mail: (CJ); (JH)
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Jiang C, Hamm JP, Lim VK, Kirk IJ, Chen X, Yang Y. Amusia results in abnormal brain activity following inappropriate intonation during speech comprehension. PLoS One 2012; 7:e41411. [PMID: 22859982 PMCID: PMC3407197 DOI: 10.1371/journal.pone.0041411] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 06/25/2012] [Indexed: 11/19/2022] Open
Abstract
Pitch processing is a critical ability on which humans’ tonal musical experience depends, and which is also of paramount importance for decoding prosody in speech. Congenital amusia refers to deficits in the ability to properly process musical pitch, and recent evidence has suggested that this musical pitch disorder may impact upon the processing of speech sounds. Here we present the first electrophysiological evidence demonstrating that individuals with amusia who speak Mandarin Chinese are impaired in classifying prosody as appropriate or inappropriate during a speech comprehension task. When presented with inappropriate prosody stimuli, control participants elicited a larger P600 and smaller N100 relative to the appropriate condition. In contrast, amusics did not show significant differences between the appropriate and inappropriate conditions in either the N100 or the P600 component. This provides further evidence that the pitch perception deficits associated with amusia may also affect intonation processing during speech comprehension in those who speak a tonal language such as Mandarin, and suggests music and language share some cognitive and neural resources.
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Affiliation(s)
- Cunmei Jiang
- Music College, Shanghai Normal University, Shanghai, China
- Institute of Psychology, Chinese Academy of Science, Beijing, China
| | - Jeff P. Hamm
- Research Centre for Cognitive Neuroscience, The University of Auckland, Auckland, New Zealand
- * E-mail: (JPH) (YY)
| | - Vanessa K. Lim
- Research Centre for Cognitive Neuroscience, The University of Auckland, Auckland, New Zealand
| | - Ian J. Kirk
- Research Centre for Cognitive Neuroscience, The University of Auckland, Auckland, New Zealand
| | - Xuhai Chen
- School of Psychology, Shaanxi Normal University, Xian, China
| | - Yufang Yang
- Institute of Psychology, Chinese Academy of Science, Beijing, China
- * E-mail: (JPH) (YY)
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Altenmüller E, Baur V, Hofmann A, Lim VK, Jabusch HC. Musician's cramp as manifestation of maladaptive brain plasticity: arguments from instrumental differences. Ann N Y Acad Sci 2012; 1252:259-65. [PMID: 22524368 DOI: 10.1111/j.1749-6632.2012.06456.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Musician's cramp is a task-specific movement disorder that presents itself as muscular incoordination or loss of voluntary motor control of extensively trained movements while a musician is playing the instrument. It is characterized by task specificity and gender bias, affecting significantly more males than females. The etiology is multifaceted: a combination of a genetic predisposition, termed endophenotype, and behavioral triggering factors being the leading features for the manifestation of the disorder. We present epidemiological data from 591 musician patients from our outpatient clinic demonstrating an influence of fine-motor requirements on the manifestation of dystonia. Brass, guitar, and woodwind players were at greater risk than other instrumentalists. High temporospatial precision of movement patterns, synchronous demands on tonic and phasic muscular activation, in combination with fine-motor burdens of using the dominant hand in daily life activities, constitute as triggering factors for the disorder and may explain why different body parts are affected.
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Affiliation(s)
- Eckart Altenmüller
- Institute for Music Physiology and Musicians' Medicine, University of Music, Drama and Media, Hannover, Germany.
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Lee H, Kydd RR, Lim VK, Kirk IJ, Russell BR. Effects of trifluoromethylphenylpiperazine (TFMPP) on interhemispheric communication. Psychopharmacology (Berl) 2011; 213:707-14. [PMID: 20924753 DOI: 10.1007/s00213-010-2025-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 09/15/2010] [Indexed: 11/30/2022]
Abstract
BACKGROUND 'Party Pills' containing trifluoromethylphenylpiperazine (TFMPP) and benzylpiperazine are legally available in many countries and marketed as safe alternatives to other illicit substances such as methamphetamine and methylenedioxymethamphetamine (or Ecstasy). They have gained huge popularity around the world, especially amongst young adults. However, there is no information currently available describing the acute neurophysiological effects of these psychoactive drugs in humans. The purpose of this study is to investigate the effects of TFMPP on central information processing speed in humans. METHODS A randomised, double blind, placebo-controlled study using electroencephalography (EEG) was carried out to investigate the effects of TFMPP on interhemispheric transfer time (IHTT). Healthy, right-handed males (age: 25 ± 5.6 years) were given placebo (n = 15) or TFMPP (0.94 mg/kg, oral, n = 15) and tested both pre- and 2 h post-drug administration. High-density EEG recordings (128 channels which were re-referenced using an average reference to make 129 electrodes) were used to record event-related potentials. The N160 component was defined as the biggest negative peak in the range between 140 and 220 ms after the event. The IHHTs were analysed by deducting the N160 latency obtained in the contralateral hemisphere from the N160 latency obtained in the hemisphere ipsilateral to stimulus signal. RESULTS Statistical analysis using a split-plot design analysis of variance revealed that TFMPP significantly reduced the IHTT but did not affect reaction time. No statistically significant changes were observed in the placebo group. CONCLUSIONS This study is the first to report the neurophysiological effects of TFMPP in humans and suggests that TFMPP may affect transmitter systems involved in speeding of interhemispheric communication in the male brain.
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Affiliation(s)
- HeeSeung Lee
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Jiang C, Hamm JP, Lim VK, Kirk IJ, Yang Y. Processing melodic contour and speech intonation in congenital amusics with Mandarin Chinese. Neuropsychologia 2010; 48:2630-9. [PMID: 20471406 DOI: 10.1016/j.neuropsychologia.2010.05.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 04/26/2010] [Accepted: 05/01/2010] [Indexed: 10/19/2022]
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Wu CC, Fairhall SL, McNair NA, Hamm JP, Kirk IJ, Cunnington R, Anderson T, Lim VK. Impaired sensorimotor integration in focal hand dystonia patients in the absence of symptoms. J Neurol Neurosurg Psychiatry 2010; 81:659-65. [PMID: 19965853 DOI: 10.1136/jnnp.2009.185637] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Functional imaging studies of people with focal hand dystonia (FHD) have indicated abnormal activity in sensorimotor brain regions. Few studies however, have examined FHD during movements that do not provoke symptoms of the disorder. It is possible, therefore, that any differences between FHD and controls are confounded by activity due to the occurrence of symptoms. Thus, in order to characterise impairments in patients with FHD during movements that do not induce dystonic symptoms, we investigated the neural correlates of externally paced finger tapping movements. METHODS Functional MRI (fMRI) was used to compare patients with FHD to controls with respect to activation in networks modulated by task complexity and hand used to perform simple and complex tapping movements. RESULTS In the 'complexity network,' patients with FHD showed significantly less activity relative to controls in posterior parietal cortex, medial supplementary motor area (SMA), anterior putamen and cerebellum. In the 'hand network,' patients with FHD showed less activation than controls in primary motor (M1) and somatosensory (S1) cortices, SMA and cerebellum. Conjunction analysis revealed that patients with FHD demonstrated reduced activation in the majority of combined network regions (M1, S1 and cerebellum). CONCLUSION Dysfunction in FHD is widespread in both complexity and hand networks, and impairments are demonstrated even when performing tasks that do not evoke dystonic symptoms. These results suggest that such impairments are inherent to, rather than symptomatic of, the disorder.
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Affiliation(s)
- C Carolyn Wu
- Department of Psychology, Research Centre for Cognitive Neuroscience, The University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand
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Lim VK, Wilson AJ, Hamm JP, Phillips N, Iwabuchi SJ, Corballis MC, Arzarello F, Thomas MOJ. Semantic processing of mathematical gestures. Brain Cogn 2009; 71:306-12. [PMID: 19665831 DOI: 10.1016/j.bandc.2009.07.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2008] [Revised: 06/11/2009] [Accepted: 07/13/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To examine whether or not university mathematics students semantically process gestures depicting mathematical functions (mathematical gestures) similarly to the way they process action gestures and sentences. Semantic processing was indexed by the N400 effect. RESULTS The N400 effect elicited by words primed with mathematical gestures (e.g. "converging" and "decreasing") was the same in amplitude, latency and topography as that elicited by words primed with action gestures (e.g. drive and lift), and that for terminal words of sentences. SIGNIFICANCE AND CONCLUSION Findings provide a within-subject demonstration that the topographies of the gesture N400 effect for both action and mathematical words are indistinguishable from that of the standard language N400 effect. This suggests that mathematical function words are processed by the general language semantic system and do not appear to involve areas involved in other mathematical concepts (e.g. numerosity).
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Affiliation(s)
- Vanessa K Lim
- Department of Psychology, Research Centre for Cognitive Neuroscience, The University of Auckland, Auckland, New Zealand.
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Dalziel SR, Lim VK, Lambert A, McCarthy D, Parag V, Rodgers A, Harding JE. Psychological functioning and health-related quality of life in adulthood after preterm birth. Dev Med Child Neurol 2007; 49:597-602. [PMID: 17635205 DOI: 10.1111/j.1469-8749.2007.00597.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The aim of this study was to determine if preterm birth is associated with socioeconomic status (SES), psychological functioning, and health-related quality of life (HRQoL) in adulthood. We used prospective follow-up of 192 adult offspring of mothers who took part in a randomized controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (66 born at term [33 males, 33 females] 126 born preterm [66 males, 60 females]). Cognitive functioning was assessed using the Wechsler Abbreviated Scale of Intelligence. Working memory and attention was assessed using the Benton Visual Retention Test, the Paced Auditory Serial Addition Test, and the Brown Attention Deficit Disorder Scale. Psychiatric morbidity was assessed using the Beck Depression Inventory II, the State-Trait Anxiety Inventory, and the Schizotypy Traits Questionnaire. Handedness was assessed using the Edinburgh Handedness Inventory. HRQoL was assessed using the Short Form-36 Health Survey. Moderately preterm birth (median gestation 34wks, mean birthweight 1946g [SD 463g]) was not related to later marital status, educational attainment, SES, cognitive functioning, working memory, attention, or symptoms of anxiety or schizotypy at 31 years of age. Preterm birth was associated with fewer symptoms of depression and higher levels of satisfaction in three of the eight HRQoL domains measured (bodily pain, general health perception, and social functioning). Adults who were born moderately preterm have SES, psychological functioning, and HRQoL consistent with those who were born at term. This good long-term outcome cannot be extrapolated to those with early childhood disability or very low birthweights.
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Affiliation(s)
- Stuart R Dalziel
- Clinical Trials Research Unit and Liggins Institute, University of Auckland, Auckland, New Zealand.
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Abstract
Health Related Quality of Life (HRQL) was assessed by the SF-36 in a group of patients with dystonia in New Zealand and Australia. The caregivers of these people were also asked to participate. Low scores from the SF-36 indicate a disability or limitation in HRQL. Compared with the national norms of the respective countries, the participants with dystonia for both countries were significantly lower in the eight dimensions of the SF-36, suggesting that patients with dystonia have lower HRQL compared with their respective national norms without dystonia. In contrast to the patients with dystonia, caregivers did not show lower HRQL scores than their national norms, suggesting that while dystonia affects the HRQL of those with the disorder, their caregivers may be less affected. Descriptive and demographic information were also gathered and are discussed. An important factor that may affect the HRQL of patients with dystonia is the length of time required to be diagnosed in this sample and the number of medical practitioners the patients consulted prior to a confirmed diagnosis.
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Affiliation(s)
- Vanessa K Lim
- Department of Psychology, The University of Auckland, Auckland, New Zealand.
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Abstract
PURPOSE To determine whether a model of two subtypes of yips is supported by evidence from a range of physiological, behavioral, and psychological measures. METHODS Fifteen golfers who experience yips symptoms while putting (mean age 58.1 yr, SD 13.6 yr), and nine golfers with no yips symptoms (mean age 39.6 yr, SD 19.3 yr) were recruited. Participants completed a golf history questionnaire to determine their playing experience and the nature of any yips symptoms experienced. In experiment 1, participants performed a putting task while electromyographic data were recorded from the forearm flexors and extensors and biceps brachii, bilaterally. The task was performed in two sessions, under low-pressure and high-pressure experimental conditions. The high-pressure condition was intended to increase anxiety through the use of a monetary incentive, video-taping of performance, and the presence of a confederate who provided negative feedback. Participants' state of anxiety was assessed using a questionnaire before each of the experimental sessions. In experiment 2, participants completed a task that required the inhibition of an anticipated response. Their accuracy and ability to inhibit their response was determined. RESULTS The golfers who experienced yips could be categorized according to whether they reported mainly movement-related symptoms (Type I) or anxiety-related symptoms (Type II). The Type I group exhibited greater muscle activity during putting and greater errors and less inhibition of the anticipated response task. The Type II group exhibited greater changes in cognitive anxiety and normal performance of the anticipated response task. CONCLUSION This study provides evidence in support of two yips subtypes. Type I is related to impaired movement initiation and execution, whereas Type II is related to performance anxiety.
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Affiliation(s)
- Cathy M Stinear
- Human Motor Control Laboratory, Department of Sport & Exercise Science, University of Auckland, Auckland, New Zealand.
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Lim VK, Hamm JP, Byblow WD, Kirk IJ. Decreased desychronisation during self-paced movements in frequency bands involving sensorimotor integration and motor functioning in Parkinson's disease. Brain Res Bull 2006; 71:245-51. [PMID: 17113953 DOI: 10.1016/j.brainresbull.2006.09.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Revised: 12/18/2005] [Accepted: 09/08/2006] [Indexed: 11/23/2022]
Abstract
This study examined sensorimotor integration and motor functioning in seven patients with Parkinson's disease (PD) who had mild symptoms, and seven age-matched controls. Neuro-oscillations were recorded by high-density 128-channel electroencephalography (EEG). Participants were required to perform two tasks: simple tapping of the index finger and thumb and a complex Luria finger apposition task. Both tasks were performed unimanually and bimanually. There were no significant group differences in the task-related power (TRPow) within alpha 1 (mu1) or in beta 1 frequencies (beta1). In contrast, there were significant group differences in the alpha 2 (mu2) and beta 2 frequencies (beta2). Patients had less desychronisation than controls at the electrodes covering the central regions of the scalp. Alpha 2 and beta 2 frequencies have been associated with task-specific sensorimotor integration and motor function, respectively. This activity difference in patients with Parkinson's disease may be due to deficits in sensorimotor integration.
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Affiliation(s)
- Vanessa K Lim
- Department of Psychology, Research Centre for Cognitive Neuroscience, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Lim VK, Polych MA, Holländer A, Byblow WD, Kirk IJ, Hamm JP. Kinesthetic but not visual imagery assists in normalizing the CNV in Parkinson's disease. Clin Neurophysiol 2006; 117:2308-14. [PMID: 16890482 DOI: 10.1016/j.clinph.2006.06.713] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2006] [Revised: 05/14/2006] [Accepted: 06/10/2006] [Indexed: 11/17/2022]
Abstract
OBJECTIVE This study investigated whether kinesthetic and/or visual imagery could alter the contingent negative variation (CNV) for patients with Parkinson's disease (PD). METHODS The CNV was recorded in six patients with PD and seven controls before and after a 10min block of imagery. There were two types of imagery employed: kinesthetic and visual, which were evaluated on separate days. RESULTS The global field power (GFP) of the late CNV did not change after the visual imagery for either group, nor was there a significant difference between the groups. In contrast, kinesthetic imagery resulted in significant group differences pre-, versus post-imagery GFPs, which was not present prior to performing the kinesthetic imagery task. In patients with PD, the CNV amplitudes post-, relative to pre-kinesthetic imagery, increased over the dorsolateral prefrontal regions and decreased in the ipsilateral parietal regions. There were no such changes in controls. CONCLUSIONS A 10-min session of kinesthetic imagery enhanced the GFP amplitude of the late CNV for patients but not for controls. SIGNIFICANCE While the study needs to be replicated with a greater number of participants, the results suggest that kinesthetic imagery may be a promising tool for investigations into motor changes, and may potentially be employed therapeutically, in patients with Parkinson's disease.
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Affiliation(s)
- Vanessa K Lim
- Department of Psychology, Research Centre for Cognitive Neuroscience, The University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Abstract
Auditory evoked potentials (AEPs) were examined in patients with musician's cramp (focal dystonia) in order to determine whether these patients have electrophysiological changes in a sensory system that is not usually associated with symptoms. All participants were professional guitarists and were required to listen to 2,000 monaurally presented stimuli (middle C, with duration of 7 ms). During one block, 250 stimuli were presented to one ear. Once a block was finished, another block was presented in the other ear; in total there were eight blocks of stimuli. During this task, EEGs from 10 scalp electrodes and one bipolar eye channel were continuously recorded. There were no significant latency or topographical differences in the electrophysiological recordings. However, there was a significant group difference in the peak-to-peak amplitude of the P1-N1a component. The patients had a larger peak-to-peak difference than controls (1.63 vs. 0.62 microV). The P1 and N1a are cortically generated potentials. Patients with focal dystonia had an increase in activity compared to controls when processing simple auditory stimuli. Such changes in electrophysiological responses may be a result of increases in excitation or lack of inhibition; alternatively the changes may represent cross-modal maladaptive plasticity from the somatosensory modality to the auditory modality. Thus, this study provides further evidence that patients with focal dystonia have alterations of the central nervous system that are not limited to their symptomatic sensory domain.
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Affiliation(s)
- Vanessa K Lim
- Department of Psychology, Unviersity of Auckland, New Zealand
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Dalziel SR, Lim VK, Lambert A, McCarthy D, Parag V, Rodgers A, Harding JE. Antenatal exposure to betamethasone: psychological functioning and health related quality of life 31 years after inclusion in randomised controlled trial. BMJ 2005; 331:665. [PMID: 16143712 PMCID: PMC1226245 DOI: 10.1136/bmj.38576.494363.e0] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To determine if antenatal exposure to betamethasone for the prevention of neonatal respiratory distress syndrome alters psychological functioning and health related quality of life in adulthood. DESIGN Follow-up of the first and largest double blind, placebo controlled, randomised trial of a single course of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome. SETTING Tertiary obstetric hospital in Auckland, New Zealand. PARTICIPANTS 192 adult offspring, mean age 31 years, of mothers who took part in a randomised controlled trial of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome (87 exposed to betamethasone and 105 exposed to placebo). INTERVENTIONS Mothers received two doses of betamethasone or placebo 24 hours apart. MAIN OUTCOME MEASURES Cognitive functioning assessed with Wechsler abbreviated scale of intelligence; working memory and attention assessed with Benton visual retention test, paced auditory serial addition test, and Brown attention deficit disorder scale; psychiatric morbidity assessed with Beck depression inventory II, state-trait anxiety inventory, and schizotypy traits questionnaire; handedness assessed with Edinburgh handedness inventory; health related quality of life assessed with short form 36 health survey. RESULTS No differences were found between groups exposed to betamethasone and placebo in cognitive functioning, working memory and attention, psychiatric morbidity, handedness, or health related quality of life. CONCLUSIONS Prenatal exposure to a single course of betamethasone does not alter cognitive functioning, working memory and attention, psychiatric morbidity, handedness, or health related quality of life in adulthood. Obstetricians should continue to use a single course of antenatal betamethasone for the prevention of neonatal respiratory distress syndrome.
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Affiliation(s)
- Stuart R Dalziel
- Clinical Trials Research Unit, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Lim VK, Bradshaw JL, Nicholls ME, Altenmüller E. Abnormal sensorimotor processing in pianists with focal dystonia. Adv Neurol 2004; 94:267-73. [PMID: 14509684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Focal dystonia is a task-specific sensorimotor disorder that is characterized by sustained muscle contractions, which may cause twisting, repetitive movements, or abnormal postures. In the current study, the contingent negative variation was recorded in a group of professional pianists with focal dystonia (musicians' cramp) and compared to pianist controls. The CNV is composed of an early stimulus processing component and a later response preparation component. The CNV can be elicited in tasks that require movement and nonmovement. A subtractive analysis with a nonmovement condition was used to minimize effects of the CNV not related to response preparation. The current results revealed no group differences for the early CNV (processing of stimulus properties). In contrast, a significant group difference was found in the late CNV (movement preparation) between patients and controls, with the patients showing significantly higher activation prior to movement. The current study demonstrates an increase in overall sensorimotor activity prior to movement in patients with musicians' cramp. This overexcitation of the cortex may be the result of a dysfunction in the globus pallidus, resulting in a lack of inhibition and/or an increase in excitation.
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Affiliation(s)
- Vanessa K Lim
- Department of Sport and Exercise Science, University of Auckland, Auckland, New Zealand
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Lim VK, Bradshaw JL, Nicholls MER, Altenmüller E. Perceptual differences in sequential stimuli across patients with musician's and writer's cramp. Mov Disord 2003; 18:1286-93. [PMID: 14639669 DOI: 10.1002/mds.10528] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previous research has demonstrated a relationship between the regularity of motor production and the ability to make accurate perceptual judgments. The current study investigated the temporal abilities of two groups of patients with known movement problems (musicians' and writers' cramp), some of whom have had many years of training in temporal discrimination. Patients and controls (musician and nonmusician, respectively) judged whether the last of six sequential auditory or tactile stimuli occurred earlier or later in comparison to five previously and regularly presented stimuli. In both sensory domains, patients with musicians' cramp detected the early stimulus better than controls. When detecting the onset of late stimuli, only in the auditory domain were patients worse than controls. Patients with writers' cramp, however, did not show any significant group differences in either auditory or tactile domains, suggesting that such patients are not deficient in processing sequential stimuli. In conclusion, compared to controls, patients with musician's cramp demonstrated generalized timing anomalies, occurring in the symptomatic (tactile) and the asymptomatic (auditory) sensory domains. This timing problem is likely to be a consequence of the dystonic symptoms rather than the cause.
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Norazah A, Lim VK, Munirah SN, Kamel AG. Staphylococcus aureus carriage in selected communities and their antibiotic susceptibility patterns. Med J Malaysia 2003; 58:255-61. [PMID: 14569746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The carriage and antibiotic susceptibility patterns of Staphylococcus aureus in the community were determined. Nasal, throat and axillary swabs were taken from 100 healthy adults and 90 disabled nursing home inmates. Antibiotic disc susceptibility testing was conducted following the NCCLS method. Staphylococcus aureus carriage was noted in 29% of healthy adults and 47.7% of nursing home inmates. Out of 79 strains, resistance to antibiotics were as follows; penicillin (92.4%), genetamicin (2.5%), tetracycline (6.3%), fusidic acid (11.3%), erythromycin (3.8%), pefloxacin (5.1%), mupirocin (3.8%), amikacin (3.8%), ciprofloxacin (2.5%) and chloramphenicol (2.5%). Methicillin-resistant Staphylococcus aureus was not isolated. Multiple colonizations and multi-antibiotic resistant Staphylococcus aureus were shown to occur in healthy individuals without risk factors and not previously hospitalized.
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Affiliation(s)
- A Norazah
- Bacteriology Unit, Infectious Diseases Research Centre, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur
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Lim VK. Antibiotic resistance in the community. Med J Malaysia 2003; 58:156-8. [PMID: 14569734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
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Altenmüller E, Schürmann K, Lim VK, Parlitz D. Hits to the left, flops to the right: different emotions during listening to music are reflected in cortical lateralisation patterns. Neuropsychologia 2003; 40:2242-56. [PMID: 12417455 DOI: 10.1016/s0028-3932(02)00107-0] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In order to investigate the neurobiological mechanisms accompanying emotional valence judgements during listening to complex auditory stimuli, cortical direct current (dc)-electroencephalography (EEG) activation patterns were recorded from 16 right-handed students. Students listened to 160 short sequences taken from the repertoires of jazz, rock-pop, classical music and environmental sounds (each n=40). Emotional valence of the perceived stimuli were rated on a 5-step scale after each sequence. Brain activation patterns during listening revealed widespread bilateral fronto-temporal activation, but a highly significant lateralisation effect: positive emotional attributions were accompanied by an increase in left temporal activation, negative by a more bilateral pattern with preponderance of the right fronto-temporal cortex. Female participants demonstrated greater valence-related differences than males. No differences related to the four stimulus categories could be detected, suggesting that the actual auditory brain activation patterns were more determined by their affective emotional valence than by differences in acoustical "fine" structure. The results are consistent with a model of hemispheric specialisation concerning perceived positive or negative emotions proposed by Heilman [Journal of Neuropsychiatry and Clinical Neuroscience 9 (1997) 439].
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Affiliation(s)
- Eckart Altenmüller
- Institute for Music Physiology and Musicians' Medicine, Hannover University for Music and Drama, Hohenzollernstr. 47, D-30161, Hannover, Germany.
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Abstract
AbstractSimple tapping and complex movements (Luria finger apposition task) were performed unimanually and bimanually by two groups of professional guitarists while EEG was recorded from electrodes over the sensorimotor cortex. One group had a task-specific movement disorder (focal dystonia or musicians' cramp), while the other group did not (controls). There were no significant group interactions in the task-related power (TRPow) within the alpha range of 8-10Hz (mu1). In contrast, there was a significant group interaction within the alpha range of 10-12Hz (mu2); these latter frequencies are associated with task-specific sensorimotor integration. The significant group interaction included task (simple and complex) by hand (left, right, and both) by electrodes (10 electrodes over the sensorimotor areas). In the rest conditions, the alpha power (10-12Hz) was comparable between the groups; during movement, however, compared to the controls, patients demonstrated the greatest TRPow (10-12Hz) over all conditions. This was particularly evident when patients used their affected hand and suggests that patients with musicians' cramp have impaired task-specific sensorimotor integration.
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Affiliation(s)
- Vanessa K. Lim
- Department of Sport & Exercise, Human Motor Control Laboratory and Department of Psychology, Research Centre for Cognitive Neuroscience, The University of Auckland, Auckland, New Zealand, Institut für Musikphysiologie und Musiker-Medizin, Hochschule für Musik und Theater Hannover, Hannover, Germany
| | | | - Michael E.R. Nicholls
- Department of Sport & Exercise, Human Motor Control Laboratory, The University of Auckland, Auckland, New Zealand
| | - Ian J. Kirk
- Department of Psychology, Research Centre for Cognitive Neuroscience, The University of Auckland, Auckland, New Zealand
| | - Jeff P. Hamm
- Department of Psychology, Research Centre for Cognitive Neuroscience, The University of Auckland, Auckland, New Zealand
| | - Michael Grossbach
- Institut für Musikphysiologie und Musiker-Medizin, Hochschule für Musik und Theater Hannover, Hannover, Germany
| | - Eckart Altenmüller
- Institut für Musikphysiologie und Musiker-Medizin, Hochschule für Musik und Theater Hannover, Hannover, Germany
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Lim VK. Foodborne diseases in Malaysia. Med J Malaysia 2002; 57:1-2. [PMID: 14569712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
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Boo NY, Nordiah AJ, Alfizah H, Nor-Rohaini AH, Lim VK. Contamination of breast milk obtained by manual expression and breast pumps in mothers of very low birthweight infants. J Hosp Infect 2001; 49:274-81. [PMID: 11740876 DOI: 10.1053/jhin.2001.1117] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to compare the rates of bacterial contamination of expressed breast milk (EBM) obtained by manual expression and breast pumps in mothers of very low birthweight (VLBW) infants (<1501 g). This was a randomized, controlled study carried out on 28 mothers of such babies and 92 specimens of EBM were collected: 41 specimens from 13 mothers assigned to the manual group and 51 specimens from 15 mothers in the breast-pump group. EBM was cultured quantitatively by the Miles and Misra method. Breast milk expressed by breast pumps (86.3% or 44/51 specimens) had a significantly higher rate of bacterial contamination than milk expressed by the manual method (61.0% or 25/41 specimens) (P= 0.005). When breast milk was expressed in the hospital, there was no significant difference in contamination rates between the two methods. When breast milk was expressed at home, the rates of bacterial contamination by staphylococci (P= 0.003) and Gram-negative bacilli (P= 0.002) were significantly higher in the breast-pump group than the manual group. In conclusion, the rate of bacterial contamination of EBM of mothers of VLBW infants was high, especially when EBM was obtained by the breast pump or when expression was carried out at home.
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Affiliation(s)
- N Y Boo
- Department of Paediatric, Hospital Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur, 56000, Malaysia.
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Abstract
Dystonia is a syndrome characterised by abnormal involuntary sustained muscle contractions that often result in twisted and abnormal positions. Focal dystonia affects only a single body part with symptoms varying from permanent (e.g., torticollis) to task-specific (e.g., musician's cramp). The exact causes of focal dystonia have yet to be determined. Possible causative factors have been identified at all levels along the sensorimotor pathway, including anatomical constraints of the hand (musicians), abnormal co-contractions of the muscles due to reciprocal inhibition in the spinal cord, subcortical and cortical remapping, deficiencies in sensorimotor integration and perceptual deficits. A review of the current literature on these topics is provided with a special focus on musicians with focal dystonia. Also reviewed are current treatments of focal dystonia in musicians. On the basis of the currently available evidence, certain risk factors are identified for the development of task-specific focal dystonia, including number of practice hours, personality, genetic predisposition, performance factors and sensory effects. In addition, it is highlighted that dystonic movements occur predominantly in the context of perceptual-motor tasks involving emotions. When emotional and motor traces have become associated, they are difficult to change; it is suggested that this mechanism plays an important role in the preservation of dystonic symptoms.
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Affiliation(s)
- V K Lim
- The Department of Psychology, School of Behavioural Sciences, The University of Melbourne, Melbourne, Vic 3010, Australia.
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Lim VK, Lambert A, Hamm JP. A paradox in the laterality of melody processing. Laterality 2001; 6:369-79. [PMID: 15513182 DOI: 10.1080/713754418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Melody lateralisation has been examined extensively, using well known behavioural techniques--dichotic/monaural listening and dual tasks. The literature using these techniques has produced paradoxical results for the lateralisation of melody processing particularly with non-musicians. Research using the dichotic/monaural listening paradigm suggests right hemisphere processing for non-musicians while the dual task paradigm has suggested a left hemisphere dominance. The current study utilises both monaural listening and dual task techniques within trials. The results replicated the paradox in the literature. The dichotic/monaural listening melody measure (d') suggest right hemisphere processing of melodies for both musicians and non-musicians. In contrast, the dual task measure suggests left hemisphere processing for the non-musicians and bilateral processing for the musicians. Both measures were collected from the same stimulus presentations and are therefore paradoxical particularly for the non-musicians. Irrespective of which task participants are primarily attending, both laterality measures should produce internally consistent patterns if they are measuring the same aspects of melody processing. Although the paradox for the musicians may be resolved by postulating an attentional bias towards the tapping task, no such explanation is possible for the non-musicians. In light of the paradoxical findings produced by these two measures, their utility for providing unambiguous information about lateralisation of mental processing is questionable.
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Affiliation(s)
- V K Lim
- Department of Psychology, School of Behavioural Sciences, The University of Melbourne, Vic., Australia
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Lim VK, Halijah MY. In vitro activity of sulperazon against recent isolates of ceftazidime-resistant bacteria. Med J Malaysia 2001; 56:365-9. [PMID: 11732084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The in vitro activity of sulperazon (cefoperazone/sulbactam) was tested against 94 ceftazidime-resistant strains of bacteria isolated from mostly seriously ill patients in critical care units. Acinetobacter baumanii, Pseudomonas aeruginosa and Klebsiella pneumoniae made up 80% of the pathogens studied; 90% of the Klebsiella strains were producers of extended-spectrum beta-lactamases (ESBL). The MIC90 of sulperazon for Klebsiella was 12 mg/l (range 1.5-16 mg/l), indicating that this drug may be a useful alternative for the treatment of ceftazidime-resistant, ESBL-producing Klebsiella.
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Affiliation(s)
- V K Lim
- Infectious Diseases Research Centre, Institute of Medical Research, Kuala Lumpur
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Affiliation(s)
- V K Lim
- Department of Microbiology, Faculty of Medicine, Hospital Universiti Kebangsaan Malaysia, 56000 Kuala Lumpur, Malaysia
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Norazah A, Koh YT, Ghani Kamel A, Alias R, Lim VK. Mupirocin resistance among Malaysian isolates of methicillin-resistant Staphylococcus aureus. Int J Antimicrob Agents 2001; 17:411-4. [PMID: 11337230 DOI: 10.1016/s0924-8579(01)00314-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Four hundred methicillin-resistant Staphylococcus aureus strains (MRSA) from different geographical areas in Malaysia were tested for mupirocin susceptibility using minimum inhibitory concentration (MIC) determination. The majority of these strains (98.75%) were susceptible to mupirocin with MICs of < or = 4 mg/l. Fifty-percent of these strains had MICs of 0.125 mg/l or less while 90% of the strains had MICs of 1 mg/l or less. Mupirocin resistance was detected in five strains (1.25%) and one of these (0.25%) had an MIC of 64 mg/l and the other four strains (1%), high-level resistance with MICs > 512 mg/l. Even though the rate of mupirocin resistance in MRSA is still low in Malaysia, its presence calls for a strict policy on mupirocin usage in Malaysian hospitals.
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Affiliation(s)
- A Norazah
- Division of Bacteriology, Institute for Medical Research, Jalan Pahang, 50588, Kuala Lumpur, Malaysia
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Lim VK. Cholera: a re-emerging infection. Med J Malaysia 2001; 56:1-3. [PMID: 11503284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Norazah A, Liew SM, Kamel AG, Koh YT, Lim VK. DNA fingerprinting of methicillin-resistant Staphylococcus aureus by pulsed-field gel electrophoresis (PFGE): comparison of strains from 2 Malaysian hospitals. Singapore Med J 2001; 42:15-9. [PMID: 11361232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
AIM OF STUDY To determine and compare the pulsed-field gel electrophoresis (PFGE) patterns of endemic MRSA strains in 2 major Malaysian hospitals and to compare the PFGE patterns with antibiotypes of the strains studied. METHODS Fifty-six MRSA strains selected randomly between September 1997 and July 1998 from Hospital Queen Elizabeth (HQE) and Hospital Umum Sarawak (HUS) were tested for antimicrobial resistance and DNA fingerprinting was carried out by pulsed-field gel electrophoresis (PFGE) technique. RESULTS Seven PFGE types were recognised (A, B, C, D, E and F). All 7 PFGE types were observed in HQE while only 2 PFGE types (B, C) were noted in HUS strains. There is a predominance of a single PFGE pattern (type B) in both hospitals, as seen in 46% of HQE strains and 89% of HUS strains. Subtype B2 was the commonest subtype in HQE while subtype B1 predominated in HUS. Strains resistant to fusidic acid and rifampicin exhibited PFGE type F that is unique to HQE. All strains were resistant to penicillin, erythromycin, cotrimoxazole, tetracycline and gentamicin. Strains with the same antibiotic susceptibility pattern can be different PFGE types. CONCLUSION Molecular typing of the MRSA by PFGE is a useful tool in the study of endemic strains present in an institution. Strains in HQE were found to be more heterogeneous than HUS strains. Common PFGE types can also be seen in both hospitals suggesting that some of the strains was genetically related and has propagated within and between the 2 hospitals. Our findings also indicate that the relationship between antibiotic susceptibility and PFGE patterns was not close and antibiograms should not be relied upon for typing strains in epidemiological studies. By knowing the DNA fingerprints of the isolates endemic in each hospital, the spread of MRSA with a particular PFGE type can be monitored within and between hospitals.
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Affiliation(s)
- A Norazah
- Division of Bacteriology, Institute for Medical Research, Jalan Pahang, Kuala Lumpur, Malaysia
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Abstract
The authors examined the perceived job image of police officers in Singapore and its differential effects on their work-related attitudes (e.g., job satisfaction, organizational commitment, and intention to quit). The authors obtained data from questionnaire surveys and focus-group interviews. Perceived job image consisted of 4 dimensions: (a) prestige, (b) integrity, (c) competence, and (d) nonroutine job nature. Results of hierarchical regression analyses suggested that the first 2 dimensions of the perceived job image construct were salient in affecting the police officers' work-related attitudes.
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Affiliation(s)
- V K Lim
- Department of Management and Organization, Faculty of Business Administration, National University of Singapore, Law Link Crescent, Singapore 117591.
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Lim VK. "Non-infectious" syndromes associated with infectious agents. Med J Malaysia 2000; 55:389-97; quiz 398. [PMID: 11200726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Over the past two decades there has been numerous new associations between chronic diseases traditionally considered non-infectious with infectious agents. This list of diseases include peptic ulcer, coronary heart disease, neuropsychiatric disorders, haematological disorders and malignancies. These associations have been made possible through improvements in diagnostic tests based on molecular biology techniques. The discovery of these associations is important as it opens up exciting opportunities for the prevention and treatment of many diseases hitherto considered incurable.
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Affiliation(s)
- V K Lim
- Department of Medical Microbiology & Immunology, Hospital Universiti Kebangsaan Malaysia, Jalan Yaccob Latif, Cheras, 56000 Kuala Lumpur
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Lim VK. Emerging and re-emerging infections. Med J Malaysia 1999; 54:287-91; quiz 292. [PMID: 10972048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
An emerging infection is defined as an infection which has newly appeared in a population while a re-emerging infection is one which has existed in the past but its incidence is rapidly increasing. The reasons for the emergence and re-emergence of infections are not well understood but appear to be associated with factors that involve the pathogen, the host and the environment. These factors are often inter-related and act together in a complex manner to bring about changes in patterns of infection. Pathogens are extremely resourceful and possess mechanisms to adapt to new hosts and environments as well as to acquire new virulence traits. Host factors include herd immunity, social behaviour and demographics. Environmental factors like the climate, deforestation and new technologies have an impact on the emergence of infections. The challenge is to contain an infection when it emerges but more importantly to prevent its emergence in the first place. As the emergence of an infection is complex and multifactorial, a multidisciplinary approach is required. Health based strategies alone are insufficient. Social, economic and environmental measures and the political will to implement appropriate policies are equally important.
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Affiliation(s)
- V K Lim
- Department of Medical Microbiology and Immunology, Hospital Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
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Lim VK, Teo TS, Teo AC, Tan KT. HIV and youths in Singapore--knowledge, attitudes and willingness to work with HIV-infected persons. Singapore Med J 1999; 40:410-5. [PMID: 10489510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
AIM OF STUDY This study examines the level of knowledge among youths in Singapore regarding HIV transmission and their attitudes towards working with a HIV-infected person at the workplace. METHOD Respondents consist of 413 youths from three educational institutions in Singapore. The survey was administered to classes which were randomly selected by the liaison persons of these three educational institutions. RESULTS Findings of this study suggest that youths in Singapore are generally clear that HIV can be transmitted through sexual contact, blood transfusion and from a woman to her unborn child. However, our data also suggest that a sizeable number of respondents still possess a number of misconceptions about how HIV can be transmitted. While available scientific data suggest that HIV cannot be transmitted through casual contact at the workplace, results of this study suggest that some elements of uncertainty and fear still prevail. This is an interesting finding as it suggests that while AIDS education and campaigns may increase knowledge and awareness about HIV transmission, they do not really reduce personal concern about the possibility of infection and the potential stigma associated with working with HIV-infected persons. CONCLUSION The implications of our findings on AIDS education are discussed.
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Affiliation(s)
- V K Lim
- Department of Organisational Behaviour, Faculty of Business Administration, National University of Singapore, Singapore
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Abstract
This study examined the relationships among three potential sources of stress, namely, demands from patients/relatives, demands from doctors, and perceived job image, and several work-related outcomes, namely, job satisfaction, organizational commitment, intention to quit, and job-induced tension. Respondents consist of nurses from two tertiary-care hospitals in Singapore. Findings of this study suggest that demands from patients/relatives, doctors, and perceived job image were significantly associated with nurses' job satisfaction, organizational commitment and job-induced tension. While demands from patients/relatives and perceived job image were significantly associated with intention to quit, the relationship between demands from doctors and nurses' intention to quit failed to reach statistical significance. Implications of the findings are discussed.
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Affiliation(s)
- V K Lim
- Department of Organizational Behaviour, Faculty of Business Administration, National University of Singapore.
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Lim VK. Imported infections. Med J Malaysia 1998; 53:1-3. [PMID: 10968128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Lim VK. Prevention of infection in the immunocompromised. Ann Acad Med Singap 1997; 26:331-5. [PMID: 9285028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Infection is an important cause of morbidity and mortality in immunocompromised patients. The high risk of infection is not only the consequence of the underlying disease but also the result of the diagnostic, monitoring and therapeutic procedures performed on these patients. Infections may be exogenous or endogenous in origin. The prevention of exogenous infections requires a high standard of hygiene. As many infections are acquired in hospitals, an effective control of nosocomial infection programme is crucial in preventing infections in the immunocompromised. Prevention of endogenous infections involves suppression of the aerobic bacterial flora (selective decontamination) and measures to maintain gastrointestinal epithelial integrity to reduce risk of translocation of intestinal flora. Boosting the host immunity through passive and active immunisation should also be considered. Prevention of infection in the immunocompromised is no easy task and requires a multidisciplinary approach.
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Affiliation(s)
- V K Lim
- Department of Microbiology, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
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Lim VK. Antibiotic prophylaxis in surgery. Med J Malaysia 1997; 52:1-2. [PMID: 10968045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
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Lim VK. Sepsis. Med J Malaysia 1996; 51:494-8; quiz 499. [PMID: 10968044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Affiliation(s)
- V K Lim
- Department of Medical Microbiology & Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur
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Kong NC, Asmah J, Lim VK, Ong PH, Adam PA. Pyomyositis revisited. Ann Acad Med Singap 1996; 25:609-11. [PMID: 8893941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Pyomyositis, purportedly a common tropical infection affecting mainly healthy adults and children, appears to be most uncommon in this region. We report a case of pyomyositis caused by a Methicillin-resistant Staphylococcus aureus (MRSA) in a previously healthy army officer. This case serves to illustrate the difficulty in recognising this disease entity, which is why many cases may have been missed. With the increasing incidence of MRSA nosocomial infections, the emergence of MRSA in a hitherto community-acquired infection poses a major concern especially since intravenous drug abuse and acquired immune deficiency syndrome (AIDS) are on the rise in our country. We hope to inculcate greater awareness of this infection.
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Affiliation(s)
- N C Kong
- Department of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
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45
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Zubaidah AW, Lim VK. Necrotizing fasciitis. Med J Malaysia 1996; 51:134-6. [PMID: 10967993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
A 31-year-old Pakistani man was admitted to hospital after sustaining a Grade I compound fracture of the mid-shaft of the left tibia and fibula following a motor vehicle accident. He developed septicaemic shock, acute renal failure and Group A streptococcal necrotizing fasciitis of the left leg. The patient underwent an above knee amputation followed by disarticulation of the left hip with extensive debridement. He was treated with benzylpenicillin, vancomycin, inotropes and continuous haemodialysis and survived without further sequelae. Subsequently, skin grafting was done over the wound site. This case highlights the role of Group A streptococcus as a cause of this rare and life-threatening infection.
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Affiliation(s)
- A W Zubaidah
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur
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46
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Lim VK. Emerging infections: the threat to Malaysia. Med J Malaysia 1996; 51:1-3. [PMID: 10967971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Lim VK, Cheong YM. In-vitro activity of cefoperazone-sulbactam combination against cefoperazone resistant clinical isolates in a Malaysian general hospital. Malays J Pathol 1995; 17:73-6. [PMID: 8935129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Beta-lactamase production is one of the major mechanisms of resistance amongst bacteria especially the enteric bacilli. The purpose of this study is to assess the in-vitro activity of Sulperazon, a combination of cefoperazone and an irreversible beta-lactamase inhibitor, sulbactam, against the cefoperazone resistant isolates of aerobic gram-negative bacilli. A total of 92 such strains were tested. It was found that at a concentration of < or = 8 mg/l of sulbactam added to cefoperazone 82% of Klebsiella spp, 100% of E. coli, 100% of Enterobacter spp, 33% of Pseudomonas aeruginosa, 67% of Pseudomonas spp and 62% of Acinetobacter spp that were resistant to cefoperazone alone were susceptible to the combination. Hence it is concluded that the addition of sulbactam to cefoperazone does expand the spectrum of the in-vitro activity of cefoperazone.
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Affiliation(s)
- V K Lim
- Department of Medical Microbiology & Immunology, Universiti Kebangsaan Malaysia, Kuala Lumpur
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Lim VK. Disinfection and the control of nosocomial infection. Med J Malaysia 1995; 50:289-90. [PMID: 8668044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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49
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Lim VK. A short history of the Medical Journal of Malaysia. Med J Malaysia 1995; 50 Suppl A:S11-3. [PMID: 10968006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Affiliation(s)
- V K Lim
- Department of Medical Microbiology and Immunology, Universiti Kebangsaan Malaysia
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50
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Lim VK. Medicine in Malaysia: microbiology and infectious diseases. Med J Malaysia 1995; 50 Suppl A:S56-9. [PMID: 10968017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Affiliation(s)
- V K Lim
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Kuala Lumpur
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