Displaying publications 1 - 20 of 375 in total

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  1. Abdul Aziz Ismail, Mazlyfarina Mohamad, Rozilawati Ahmad, Ahmad Bazlie Abdul Kadir
    Jurnal Sains Kesihatan Malaysia, 2015;15(22):173-178.
    MyJurnal
    The aims of this study were to compare the entrance surface dose (ESD) between anteroposterior (AP) supine with
    posteroanterior (PA) prone projection of computed radiography (CR) abdominal examination and to determine the
    relationship between body mass index (BMI) and ESD of a patient. AP supine and PA prone projections on the same
    patients for CR abdominal examination of intravenous urography (IVU) were acquired on 50 patients at Hospital Raja
    Permaisuri Bainun, Ipoh. All the radiographic examinations were carried out on a Siemens Multixtop general x-ray unit
    and the images were processed with CR Carestream Direct view Max. Entrance surface dose (ESD) in miligray (mGy)
    was measured using optical stimulated luminescence dosimeters (OSLD) calibrated by the Malaysian Nuclear Agency.
    Data were analyzed using dependent t-test comparing the AP and PA projections on the same subject and Pearson
    correlation was used to determine the relationship between BMI and percentage of reduction of ESD. Results showed a
    significant different (p < 0.01) between AP supine (mean ESD = 6.42 ± 7.13 mGy) and PA prone (mean ESD = 3.92 ± 3.56
    mGy) projection at all BMI. The BMI has a positive correlation with percentage of reduction of ESD (r = 0. 61) and was
    statistically significant (p < 0.01). In conclusion, PA abdomen prone projection significantly reduces the radiation dose
    and there is a positive correlation between BMI and percentage of reduction of ESD. The use of PA prone projection for
    CR abdominal examination should be considered as the routine projection at all BMIs level. Awareness that as the BMI
    increases the ESD also increases at a moderate positive linear relationship.
  2. Abdul Aziz Ismail, Nur Shakila Othman, Mazlyfarina Mohamad, Rozilawati Ahmad
    MyJurnal
    Body sizes of patients undergoing x-ray examination vary in body mass index (BMI) and waist circumference (WC). This study aimed to evaluate the relationship between BMI and WC on the image quality of abdominal computed radiography (CR). Anteroposterior supine abdomen projection was conducted on 69 patients from Hospital Raja Perempuan Bainun, Ipoh using a Siemens Multixtop general x-ray unit, and the images were processed with CR Carestream Direct view Max. Samples were categorised into normal BMI (n = 23), overweight (n = 23) and obese (n = 23). Image quality was measured quantitatively in signal-to-noise ratio (SNR) and qualitatively by visual grading analysis (VGA) based on the Commission of the European Communities (CEC) image criteria. Data were analysed by analysis of variance (ANOVA) and Pearson’s correlation for comparison and determining the relationship among BMI, WC and image quality. Results showed a significant difference (p < 0.01) in image quality of VGAmean (normal = 4.40 ± 0.15, overweight = 4.35 ± 0.13, obese = 4.03 ± 0.34) and SNRmean (normal = 60.79 ± 2.19, overweight = 59.66 ± 1.68, obese = 55.78 ± 4.31). A moderate to high negative correlation existed between SNR (r = −0.73), VGA (r = −0.7) with BMI (p < 0.01) and between SNR (r = −0.83), VGA (r = −0.79) with WC (p < 0.01). This study suggests that WC has a higher negative linear relationship than BMI and can be used as an effective image quality predictor for abdominal CR examination.

  3. Abdul Halim Mansar, Muhammad Aadeel T., Khairul Osman, Sharin Iskandar, A.W.
    MyJurnal
    The abdominal pelvic cavity has always been regarded as one of the most vulnerable regions of the body. Injuries to this part have been known to be very serious. Based on this a retrospective study was performed on postmortem cases with abdominal and pelvic trauma from 1 October 2002 to 31 January 2003 at the Forensic Institute, Hospital Kuala Lumpur to determine the common pattern of abdomino-pelvic injuries, the injury’s relationship to epidemiological and socio-economic factors, risk organ within the abdominopelvic region and relationship between injuries and survival period. A total of 122 cases abdomino-pelvic were obtained stemming from medico legal postmortems procedures. Results indicated that those aged between 21 to 30 years (38.5%) had the highest incidence of this type of injury. Categorization based on gender showed that males (90.2%) dominated most of the cases. Prevalence based on socio-economic status showed that lower socioeconomy class (52.5%) had the highest incident. This was followed by the middle income (39.3%) and finally the higher income group. The most numerous type of trauma was non-penetrating trauma (94.3%). It was also found that victims with low injury severity score (ISS) had a longer survival period as compared to those with high ISS. It was also noted that victims with two or more region injuries either were spot dead or brought dead. The most common combination of injuries was abdomen, pelvic, chest and limb. In most blunt trauma cases majority of victims had one or two organ involvement while penetrating injuries were difficult to asses. The most common organ involved in this type of trauma was liver (72.1%), pelvic bone (47.5%) and spleen (43.4%). In conclusion, abdomino-pelvic injury is a serious condition and should not be overlooked. Proper attention towards their diagnosis and management is important and so any patient of head injury with coma must be considered as having intra-abdominal injury until proven otherwise.
  4. Abdul Hamid Abdul Aziz, Nur Fariza Mat Reffin, Mohamed Kamel Abd Ghani, Hing, Hiang Lian, Ahmad Zorin Sahalan
    MyJurnal
    Suatu kajian mengenai pemencilan dan pengenalpastian mikroflora bakteria dari kolam air panas telah dilakukan di kolam air panas Bentong, Pahang. Kebanyakan bakteria yang dipencil dari kolam air panas adalah dari Bacillus sp. kerana ia mempunyai ciri adaptasi yang membolehkannya hidup di kawasan suhu yang tinggi dengan pembentukan endospora. Objektif kajian adalah untuk mengenal pasti spesies bakteria selain daripada spesies Bacillus sp. yang boleh dipencilkan dari kolam air panas. Tiga buah kolam air panas (A, B dan C) dikenal pasti dengan julat suhunya antara 36°C-52°C dan nilai pH antara 7.88-8.65. Kajian ini telah berjaya memencilkan dua pencilan bakteria kokus Gram positif dan tiga spesies basilus Gram negatif. Spesies Gram positif tersebut adalah dari genus Streptococcus dan Staphylococcus, manakala bagi Gram negatif pula terdapat masalah dalam pengenalpastian dan hanya dikenali sebagai X, XI and XII.


  5. Abdul Hamid Abdul Aziz, Mohamed Kamel Abd Ghani, Ahmad Zorin Sahalan, Hing, Hiang Lian
    MyJurnal
    Suatu kajian pemencilan dan pengenalpastian mikroflora bakteria daripada kolam air panas telah dilakukan di kolam
    air panas Bentong, Pahang. Kebanyakan bakteria yang dipencil dari kolam air panas adalah dari Bacillus sp. kerana ia
    mempunyai ciri adaptasi yang membolehkannya hidup di kawasan ekstrem suhu tinggi dengan pembentukan endospora.
    Objektif kajian adalah untuk mengenal pasti spesies bakteria selain dari spesies Bacillus sp. yang mampu mandiri dalam
    kolam air panas ini. Tiga buah kolam air panas dikenal pasti sebagai A, B dan C. Julat suhu berada antara 36°C-52°C
    dan nilai pH antara 7.88-8.65. Kajian ini telah berjaya memencilkan dua isolat bakteria kokus Gram positif bersama
    tiga spesies Gram negatif. Spesies Gram positif tersebut adalah dari spesies Streptococcus sp. dan Staphylococcus sp,
    manakala Gram negatif pula dikenal pasti sebagai Pseudomonas sp., Klebsiella sp. dan Proteus sp.. Sebagai kesimpulan,
    bakteria tak berspora yang bukan Bacillus sp. mampu mandiri dalam kolam air panas.
  6. Abdul Muhaimin, Mazlyfarina Mohamad, Abdul Muhaimin, Haifa Abdul Latif, Mazeni Alwi
    Jurnal Sains Kesihatan Malaysia, 2017;15(22):121-125.
    MyJurnal
    The assessment for patient with duct-dependent pulmonary circulation (DDPC) during the inter-stage intervals before first
    stage palliation commonly includes imaging of the heart with multiple imaging modalities. Recently, three-dimensional
    echocardiography (3DE) was found with the ability to delineate cardiac structure that is able to do 360o
    rotation. Therefore,
    this study aimed at identifying the accuracy of 3DE colour flow in measuring PDA size compared to computer tomography
    angiography (CTA). This study involves randomly selected 26 patients with DDPC undergoing CTA for palliation treatment
    in one year. The mean patient age is 1.6 ± 0.261 months with mean weight of 3.65 ± 0.82 kg. The full-volume 3DE colour
    flow acquisition was performed and analysed offline using Q-lab software. The PDA diameters at the origin as well as the
    insertion site were measured. The data obtained by 3DE colour flow data were compared to the CTA, which was taken as
    the gold standard. Results showed that the offline analysis of PDA size was feasible in all patients (100%) with the mean
    diameter of PDA at the origin on 3DE colour flow and CTA of 0.51 mm ± 0.14 and 0.52 mm ± 0.11, respectively (p = 0.92)
    . The PDA diameter at insertion site on 3DE colour flow and CTA was 0.29 mm ± 0.08 and 0.27 mm ± 0.97 respectively (p
    = 0.5). Meanwhile, the measurement of 3DE colour flow is comparable to CTA in measurement PDA size. However, the use
    of 3DE colour flow in infants with rapid heart rate is yet challenging to 3DE colour flow acquisitions.
  7. Abrar Hussain, Kalaivani Chellappan, Siti Zamratol Mai Sarah Mukari
    Jurnal Sains Kesihatan Malaysia, 2018;16(101):211-212.
    MyJurnal
    Difficulty of understanding speech in noise among the elderly necessitates the need for Auditory Training which has made a renewal of interest in the last decade with the auditory training applications. This interest is perhaps spurred by advances in computer-based technology. In computer-based auditory training, speech signals are considered as auditory training stimuli where input speech signals need to be verified prior to training as the speech signals are mixed with noise signals. Computer-based Auditory Training System can be embedded with input speech verifying module. Input speech verifying module is employed with speech and noise separator simulator. This simulator needs to guarantee accurate separation of speech from noise signals. Therefore, in this research, Exploratory Projection Pursuit (EPP) technique under semi-Blind Source Separation (BSS) method is intended to separate the speech source signals which are mixed with competing speech (multitalker speech babble). This training uses Malay language based sentences which differ in word length and hence number of sample values. The experimental simulation considers two-channel random, linear mixing of speech sources and competing speech. The aim of this study is to evaluate the performance of source separation using the anticipated EPP technique for various sample values of speech signals which varies in time duration due to word length dissimilarity. Simulation results show that EPP technique is feasible for source separation. As a consequence, high correlation value of r ≥ 0.99 is obtained between extracted speech signal and original speech signal for all categories of speech signals. It is further verified by the maximum nongaussianity of extracted speech signal which has high kurtosis value of 32 approximately.
  8. Abu Hassan Shaari NS, Abdul Manaf Z, Shahar S, Mohamad Ali N, Mohamed Ismail NA
    MyJurnal
    Peer-reviewed articles on the usage of mobile applications in the management of diabetes were reviewed. Studies using mobile device applications for diabetes interventions published between January 2007 and March 2013 were included in this review. Studies related to the developmental processes of the mobile applications were excluded. The characteristics of these studies and the outcomes of the methods used in the management of diabetes were gathered. We retrieved a total of 372 articles from ACM Digital library, PubMed and Proquest Medical Library. After applying the inclusion and exclusion criteria, 8 articles were eligible for further review. Most of the studies included in this review showed the effectiveness of mobile applications in diabetes management. Their major contribution comes from feedback functions of the systems that assist participants in the self-monitoring of their blood glucose and dietary intake. However, the majority of the studies showed the limited use of the mobile phone as a tool to input information into systems which would in turn convey a reminder message to the patient. In conclusion, with its features of portability and convenience, mobile application used in the management of diabetes has the potential to improve glycaemic control, resulting in significant clinical and financial benefits.
  9. Agusta, Istiqomah, Jacinta Santhanam, Yap, Wei Boon
    MyJurnal
    In the search for universal vaccine candidates for the prevention of avian influenza, the non-structural (NS)-1 protein of avian influenza virus (AIV) H5N1 has shown promising potential for its ability to effectively stimulate the host immunity. This study was aimed to produce a bacterial expression plasmid using pRSET B vector to harbour the NS1 gene of AIV H5N1 (A/Chicken/Malaysia/5858/2004 (H5N1)) for protein expression in Escherichia coli (E. coli). The NS1 gene (687 bp) was initially amplified by polymerase chain reaction (PCR) and then cloned into a pGEM-T Easy TA vector. The NS1 gene was released from pGEM-T-NS1 using EcoRI and XhoI restriction enzymes (RE). The pRSET B vector was also linearized using the same RE. The digested NS1 gene and linearized pRSET B were ligated using T4 DNA ligase to form the expression plasmid, pRSET B-NS1. The NS1 gene sequence in pRSET B-NS1 was confirmed by DNA sequencing. To prepare recombinant bacterial cells for protein expression in the future, pRSET B-NS1 was transformed into E. coli strain BL21 (DE3) by heat-shock. Colonies bearing the recombinant plasmid were screened using PCR. The DNA sequencing analysis revealed that the NS1 gene sequence was 97% homologous to that of AIV H5N1 A/Chicken/Malaysia/5858/2004 (H5N1). These results indicated that the NS1 gene of influenza A/Chicken/Malaysia/5858/2004 (H5N1) was successfully amplified and cloned into a pRSET B vector. Bacterial colonies carrying pRSET B-NS1 can be used for the synthesis of NS1-based influenza vaccine in the future and thereby aid in the prevention of avian influenza.
  10. Ahmad Firdaus Mohd Salleh, Anita Talib, Mohamed Abdullah Marwi, Noor Hayati Mohd Isa, Syamsa Rizal Abdullah, Raja Muhammad Zuha Raja Kamal Bashah, et al.
    MyJurnal
    Chrysomya megacephala (Fabricius) dan Chrysomya rufifacies (Macquart) adalah merupakan dua spesies lalat penting yang boleh dijadikan sebagai penunjuk terbaik untuk menganggarkan selang masa kematian atau Post Mortem Interval (PMI) untuk kegunaan dalam sains forensik. Penentuan PMI adalah berdasarkan kepada saiz dan peringkat perkembangan larva. Kajian perkembangan telur, larva dan pupa lalat Ch. megacepahala dan Ch. rufifacies dijalankan di bawah suhu 27ºC, 30ºC dan 33ºC di makmal dengan menggunakan kebuk pertumbuhann serangga. Data daripada kajian digunakan untuk menghasilkan satu graf pertumbuhan dan Jam Darjah Terkumpul (ADH) bagi kedua-dua spesies. Ch. megacephala mengambil masa selama 9.15 hari pada suhu 27ºC, 8.54 hari (30ºC) dan 6.76 hari (33ºC) untuk melengkapkan satu kitar hidup. Pada C. rufifacies pula, kitar hidupnya lebih lama berbanding Ch. megacephala iaitu 9.92 hari pada suhu 27ºC, 9.13 hari (30ºC) dan 7.44 hari (33ºC). Telur bagi kedua-dua spesies menetas lebih cepat pada suhu 33ºC berbanding dua suhu yang lainnya. Nilai ADH yang rendah pada sesuatu suhu, menunjukkan sesuatu spesies lebih cepat melengkapkan suatu kitar hidup. Penemuan ini berguna dalam menganggarkan selang masa kematian bagi mayat yang dijumpai pada suhu persekitaran yang berlainan.
  11. Ahmad MA, Ajit Singh DK, Chua WQ, Abd Rahman NNA, Mohd Padzil FA, Hendri ENM
    Jurnal Sains Kesihatan Malaysia, 2018;16(101):171-177.
    MyJurnal
    Knee osteoarthritis (OA) is a common chronic joint disease that results in pain and disability in many people. Cultural practice may influence patients’ views about their condition, its related issues and management. The aim of our study was to explore the perspective about knee OA and its related issues among Malaysian patients with knee OA. Twelve patients diagnosed with knee OA (8 females and 4 males) attending physiotherapy sessions at a University Hospital, mean age (SD): 67.1(9.4) years and median visual analog scale score of 5/10 participated in this qualitative study. One to one in-depth interviews were conducted, audio recorded and later transcribed verbatim. Three main themes were identified from the transcribed data; knee pain and its’ related issues (reason and aggravating factors of knee pain, coping strategies), impact of knee pain (impact on daily activities and emotions) and physiotherapy management (effects and expectations of physiotherapy, compliance and adherence towards home exercises). Most participants expressed that their knee pain was aggravated by certain movements that had an effect on their daily activities namely squatting. The findings also suggested that physiotherapy management was perceived as secondary prevention rather than a cure. Findings from this study provides information about the perceptions and related issues of patients with knee OA. This information may help health professionals in tailoring patient-centered care and provide better management.
    Study site: Physiotherapy department, Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
  12. Ahmad Nazlim Yusoff, Mohd Harith Hashim, Mohd Mahadir Ayob, Iskandar Kassim
    MyJurnal
    Kajian garis pangkal pengimejan resonans magnet kefungsian (fMRI) telah dijalankan di Jabatan Radiologi, Hospital Universiti Kebangsaan Malaysia ke atas seorang subjek lelaki sihat berumur 25 tahun menggunakan sistem pengimejan resonans magnet (MRI) 1.5 T. Kajian ini menggunakan gerakan jari tangan kanan dan kiri untuk merangsang aktiviti neuron di dalam korteks serebrum. Subjek diarahkan supaya menekan jari-jari pada ibu jari secara bergilir-gilir semasa imbasan kefungsian dilakukan. Paradigma 5 kitar aktifrehat digunakan dengan setiap kitar masing-masing mengandungi 20 siri pengukuran. Keputusan menunjukkan bahawa rantau otak yang aktif akibat gerakan jari adalah girus presentral merangkumi kawasan motor primer. Pengaktifan otak adalah secara kontralateral terhadap gerakan jari tangan kanan dan kiri. Keamatan isyarat keadaan aktif didapati lebih tinggi daripada keamatan isyarat keadaan rehat. Analisis yang dilakukan ke atas beberapa rantau pengaktifan yang diminati (ROI) pada beberapa hirisan menunjukkan perbezaan yang bererti (p < 0.05) antara keamatan keadaan aktif dan rehat untuk nilai ambang statistik (Z) = 1.0 dan 1.5. Perbezaan purata antara kedua-dua purata keamatan isyarat keadaan aktif dan rehat pada manamana hirisan untuk kedua-dua nilai Z menunjukkan magnitud pengaktifan yang lebih tinggi pada hemisfera kanan otak iaitu apabila subjek menggerakkan tangan kirinya. Bilangan voksel yang aktif juga didapati lebih tinggi pada hemisfera kanan berbanding pada hemisfera kiri otak. Keputusan ini menyokong fakta bahawa bagi subjek yang tidak kidal, kawasan pengaktifan motor pada hemisfera kanan otak semasa gerakan jari tangan kiri mengalami rangsangan hemodinamik yang lebih tinggi berbanding dengan hemisfera kiri otak semasa gerakan jari tangan kanan. Fenomena rangsangan hemodinamik yang diperhatikan dalam kajian ini dibincangkan berdasarkan kepada kebergantungan kontras isyarat kepada aras oksigen darah (BOLD).
  13. Ahmad Nazlim Yusoff, Mohd Harith Hashim, Mohd Mahadir Ayob, Iskandar Kassim
    MyJurnal
    Kajian garis pangkal pengimejan resonans magnet kefungsian (fMRI) telah dijalankan ke atas 2 orang subjek lelaki sihat (kidal dan tidak kidal) masing-masing berumur 22 dan 25 tahun. Imbasan fMRI dijalankan menggunakan sistem pengimejan resonans magnet (MRI) 1.5 T di Jabatan Radiologi, Hospital Universiti Kebangsaan Malaysia. Kajian ini menggunakan gerakanjari tangan kanan dan kiri untuk merangsang aktiviti neuron di dalam korteks serebrum. Paradigma 5 kitar aktifIrehat digunakan dengan setiap kitar mengandungi satu blok aktif dan satu blok rehat yang masing-masing mengandungi 10 siri pengukuran. Imej fMRI dianalisis menggunakan pekej perisian MatLab dan pemetaan statistik berparameter 2 (sPM2). Proses pendaftaran jasad tegar menggunakan penjelmaan afin 6 parameter dilakukan ke atas kesemua imej kefungsian berwajaran T2*. Keputusan menunjukkan bahawa pergerakan subjek adalah minimum sama ada dalam arah translasi (< 1 mm) atau putaran (< 1 ). Kesemua imej dinormalkan melalui proses peledingan tak linear menggunakan penjelmaan afin 12 parameter dan didapati sepadan dengan pencontoh yang telahpun mematuhi ruang anatomi piawai. Walau bagaimanapun, bentuk, resolusi dan kontras imej kefungsian telah berubah sedikit berbanding dengan imej asal. Pelicinan imej menggunakan kernel Gaussian isotropik 6 mm menyebabkan data imej lebih bersifat parametrik dengan kehilangan yang ketara dalam resolusi dan kontras. Pengasingan struktur yang dilakukan ke atas imej berwajaran T1 mengklaskan tisu otak kepadajirim kelabu, jirim putih dan bendalir serebrospina. Pasca pemprosesan ruang bagi imej kefungsian dan struktur menjadikan data imej bersifat parametrik dengan taburan jenis Gaussian dan sedia untuk dianalisis menggunakan model linear am dan teori medan rawak Gaussian.
  14. Ahmad Nazlim Yusoff, Mazlyfarina Mohamad, Mohd Mahadir Ayob, Mohd Harith Hashim
    MyJurnal
    A functional magnetic resonance imaging (fMRI) study was conducted on 4 healthy male and female subjects to investigate brain activation during passive and active listening. Two different experimental conditions were separately used in this study. The first condition requires the subjects to listen to a simple arithmetic instruction (e.g. one-plus-two-plus-three-plus-four) - passive listening. In the second condition, the subjects were given the same series of arithmetic instruction and were required to listen and perform the calculation - active listening. The data were then analysed using the Statistical Parametric Mapping (SPM5) and the MATLAB 7.4 (R2007a) programming softwares. The results obtained from the fixed (FFX) and random effects analyses (RFX) show that the active-state signal intensity was significantly higher (p < 0.05) than the resting-state signal intensity for both conditions. The results also indicate significant differences (p < 0.001) in brain activation between passive and active listening. The activated cortical regions during passive listening, as obtained from the FFX of the first condition is symmetrical in the left and right temporal and frontal lobes covering the cortical auditory areas. However, for the second condition, which was active listening, more activation occurs in the left hemisphere with a reduction in the number of activated voxels and their signal intensity in the right hemisphere. Activation mainly occurs in the middle temporal gyrus, precentral gyrus, middle frontal gyrus, superior temporal gyrus and several other areas in the frontal lobes. The point of maximum signal intensity has been shifted to a new coordinates during active listening. It is also observed that the magnetic resonance signal intensity and the number of activated voxel in the right and left superior temporal lobes for the second condition have been reduced as compared to that of the first condition. The results obtained strongly suggest the existence of functional specialisation. The results also indicate different networks for the two conditions. These networks clearly pertain to the existence of functional connectivity between activation areas during listening and listening while performing a simple arithmetic task.
  15. Ahmad Nazlim Yusoff, Mohd Harith Hashim, Mohd Mahadir Ayob, Iskandar Kassim
    MyJurnal
    Kajian garis pangkal pengimejan resonans magnet kefungsian (fMRI) telah dijalankan ke atas 2 orang subjek lelaki sihat dominan tangan kanan dan kiri. Kajian ini menggunakan gerakan jari tangan kanan dan kiri untuk merangsang aktiviti neuron di dalam korteks serebrum. Subjek diarahkan supaya menekan jari-jari pada ibu jari secara bergilir-gilir semasa imbasan fMRI dilakukan. Paradigma 5 kitar aktif-rehat digunakan dengan setiap kitar mengandungi satu blok aktif dan satu blok rehat dengan 10 siri pengukuran untuk setiap blok. Seratus isipadu imej fMRI bagi setiap subjek dianalisis menggunakan pekej perisian MatLab dan SPM2. Model linear am (GLM) digunakan untuk menganggar secara statistik parameter yang mencirikan model rangsangan hemodinamik bagi gerakan jari. Kesimpulan mengenai pengaktifan otak yang diperhatikan dijana secara statistik berasaskan teori medan rawak (RFT) Gaussian. Keputusan menunjukkan bahawa rantau otak yang aktif akibat gerakan jari adalah pada girus presentral merangkumi kawasan motor primer. Pengaktifan otak adalah secara kontralateral terhadap gerakan jari tangan kanan dan kiri. Keamatan isyarat keadaan aktif didapati lebih tinggi secara bererti (p < 0.001) daripada keamatan isyarat keadaan rehat. Bilangan voksel yang aktif didapati lebih tinggi pada hemisfera otak yang mengawal gerakan jari bagi tangan yang tidak dominan untuk kedua-dua subjek. Keputusan ini menyokong fakta bahawa kawasan pengaktifan motor pada hemisfera otak semasa gerakan jari tangan yang tidak dominan mengalami rangsangan hemodinamik yang lebih tinggi dan kawasan pengaktifan yang lebih luas berbanding dengan kawasan pengaktifan pada hemisfera otak yang mengawal gerakan jari bagi tangan yang dominan.
  16. Ahmad Nazlim Yusoff
    MyJurnal
    Kajian pengimejan resonans magnet kefungsian (fMRI) subjek tunggal ini menyelidiki kesan daya dan laju tepikan ke atas sifat pengaktifan korteks berkaitan motor semasa tepikan jari rentak sendiri secara bilateral. Subjek melakukan empat cara tepikan jari rentak sendiri iaitu sentuh-perlahan (SP), sentuh-laju (SL), tekan-perlahan (TP) dan tekan-laju (TL) dalam satu imbasan fMRI. Model linear am (GLM) digunakan dalam penjanaan pengaktifan otak. Pentaakulan statistik kemudiannya dibuat mengenai pengaktifan otak menggunakan teori medan rawak (RFT) Gaussian pada aras keertian diperbetulkan (α = 0.05), dengan andaian tiada pengaktifan berlaku. Keputusan mendapati otak mengkoordinasi tepikan jari bilateral rentak sendiri dengan penglibatan korteks berkaitan motor iaitu girus presentral (PCG) bilateral, serebelum bilateral dan juga kawasan motor tambahan (SMA). Peningkatan daya tepikan menonjolkan pengaktifan yang bererti (p < 0.05 diperbetulkan) pada PCG bilateral (Kawasan Brodmann (BA) 6) sejajar dengan fungsinya dalam mencetus tindakan motor seperti mengawal daya tepikan. Peningkatan laju tepikan pula menyebabkan peningkatan pengaktifan otak secara bererti (p < 0.05 diperbetulkan) hanya pada korteks kesatuan somatoderia iaitu pada lobus parietal superior (SPL) kanan atau BA7 kanan. Ini mencadangkan bahawa SPL memainkan peranan penting dalam mengkoordinasi pergerakan berkemahiran terancang.


  17. Ahmad Nazlim Yusoff, Mazlyfarina Mohamad, Khairiah Abdul Hamid, Aini Ismafairus Abd Hamid, Hanani Abdul Manan, Mohd Harith Hashim
    MyJurnal
    This study investigated the functional specialisation characteristics of brain in multiple right-hand dominant subjects pertaining to the activation of the cerebral motor cortices evoked by unilateral finger tapping, especially in primary motor (M1) and supplementary motor (SMA) areas. This multiple-subject study used unilateral (UNIright and UNIleft) selfpaced tapping of hand fingers to activate the M1 and SMA. Brain activation characteristics were analysed using statistical parametric mapping (SPM). Activation for UNIright and UNIleft showed the involvement of contralateral and ipsilateral M1 and SMA. A larger activation area but with a lower percentage of signal change (PSC) were observed in the left M1 due to the control on UNIright (4164 voxels at a = 0.001, PSC = 1.650) as compared to the right M1 due to the control on UNIleft (2012 voxels at a = 0.001, PSC = 2.377). This is due to the influence of the tapping rate effects which is greater than what could be produced by the average effects of the dominant and sub-dominant hands. The significantly higher PSC value observed in the right M1 (p < 0.05) is due to a higher control demand used by the brain in coordinating the tapping of the sub-dominant fingers. The findings obtained from this study showed strong evidence of the existence of brain functional specialisation and could be used as baseline references in determining the most probable motor pathways in a sample of subjects.
  18. Ahmad Nazlim Yusoff, Teng Xin Ling, Aini Ismafairus Abd Hamid, Siti Zamratol-Mai Sarah Mukari
    Jurnal Sains Kesihatan Malaysia, 2016;14(2):119-127.
    MyJurnal
    Despite a vast number of studies that were focused on the roles of superior temporal gyrus (STG) and cerebellum as sensory
    area, little is known about their involvement in cognitive function such as attention and perception. The present fMRI
    study aimed to identify this cognitive role from brain activation profile of STG and cerebellum obtained from an arithmetic
    addition task. Eighteen healthy right hand dominance male adults participated in this study. They were instructed to solve
    single-digit addition tasks in quiet and noisy background during the fMRI scan. Both the in-quiet and in-noise addition
    tasks activated the bilateral STG and cerebellum (lobule VI and lobule VII) significantly but differentially. In both quiet
    and noisy conditions, STG activation is dominant in the left hemisphere while cerebellum showed a right hemisphere
    dominance. Bilateral STG and cerebellum (lobule VI) activation decreasedin noise, conversely cerebellum (lobule VII)
    activation increased in noise. These asymmetrical activation indicated hemispheric lateralization and differential behaviors
    of both brain areas in different environment while performing simple arithmetic addition task.
  19. Ahmad Nazlim Yusoff, Khairiah Abdul Hamid, Farah Nabila Ab Rahman, Mazlyfarina Mohamad, Khairiah Abdul Hamid, Siti Zamratol-Mai Sarah Mukari
    MyJurnal
    In this study, the asymmetry of the main effects of action, background and tonal frequency during a pitch memory processing
    were investigated by means of brain activation. Eighteen participants (mean age 27.6 years) were presented with low and
    high frequency tones in quiet and in noise. They listen, discriminate and recognize the target tone against the final tone
    in a series of four distracting tones. The main effects were studied using the analysis of variance (ANOVA) with action (to
    wring (rubber bulb) vs. not to wring), background (in quiet vs. in noise) and frequency (low vs. high) as the factors (and
    levels respectively). The main effect of action is in the right pre-central gyrus (PCG), in conformation with its contralateral
    behavior. The main effect of background indicated the bilateral primary auditory cortices (PAC) and is right lateralized,
    attributable to white noise. The main effect of frequency is also observed in PAC but bilaterally equal and attributable to
    low frequency tones. Despite the argument that the temporo-spectral lateralization dichotomy is not especially rigid as
    revealed by the main effect of frequency, right lateralization of PAC for the respective main effect of background clearly
    demonstrates its functional asymmetry suggesting different perceptual functionality of the right and left PAC.
  20. Ahmad Nazlim Yusoff, Khairiah Abdul Hamid, Saemah Rahman, Shahlan Surat, Syazarina Sharis Osman, Maziah Ahmad Marzuki
    Jurnal Sains Kesihatan Malaysia, 2018;16(2):101-111.
    MyJurnal
    Inferior parietal lobule (IPL) and inferior temporal gyrus (ITG) are two important brain regions for the default mode
    network (DMN). IPL has been known to be involved in the control of attention and responding to given information while
    ITG is involved in the processing and perception awakened by visual stimuli. These two key DMN regions are highly
    interconnected as determined from white matter and fiber tracking studies. However, little is known about their nature
    of connectivity while the brain is at rest, whether it is linear, bilinear or nonlinear and whether it is of mono- or bidirection. Resting state functional magnetic resonance imaging (rsfMRI) data were obtained from 7 healthy male and
    female participants (average age = 20.7 ± 4.5 years) and were concatenated. Data were analyzed using statistical
    parametric mapping (SPM12). Endogenous brain signals were modelled by Fourier series at 0.01 – 0.08 Hz. IPL-ITG
    connected linear, bilinear and non-linear causal models in both hemispheres were constructed and estimated by means of
    stochastic dynamic causal modelling (sDCM) and were compared using Bayesian Model Selection (BMS) for group studies.
    Group fixed-effects results indicated that bilateral IPL and ITG exhibited high neural activity at a corrected significant
    level (pFWE < 0.05). Neural activity was centered in ITG (-32/2/-38) in the left hemisphere but shifted to IPL (32/-38/50) in
    the right hemisphere indicating different control center for both hemispheres. BMS selected bilinear model as the optimal
    model for both hemispheres (model posterior probability ~ 1.0; log evidence > 1000) which has the best balance between
    model accuracy and difficulty. The minimum free energy (F) = -4.41 × 104
    and -4.09 × 104
    for left and right hemisphere
    bilinear models respectively. From BMS and DCM results, it was found that IPL and ITG do have a dynamic collaboration
    between each other, a connectivity that belongs to a greater network when the brain is at rest. The intrinsic connections
    between them are negative in both directions i.e. IPL and ITG mutually inhibited each other. The effective connectivity
    was modulated by the endogenous fluctuation of the brain signal.
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