Papers by Kalai Muthusamy
ABSTRACTBackgroundThe availability of deep brain stimulation (DBS), a highly efficacious treatmen... more ABSTRACTBackgroundThe availability of deep brain stimulation (DBS), a highly efficacious treatment for several movement disorders, remains low in developing countries, with scarce data available on utilization and outcomes.ObjectivesWe characterized the DBS cohort and outcomes at a Malaysian quaternary medical centre.MethodsA retrospective chart review was done on DBS-related surgery at the University of Malaya, including clinico-demographic, genetics, and outcomes data focusing on post-operative medication reduction and complications.Results149 Parkinson’s disease (PD) patients underwent DBS targeting the subthalamic nucleus. Six had globus pallidus internus DBS (primarily for dystonia). Only 16.1% of cases were government-funded. Of the 133 PD patients operated in the past decade (2013-2022), 25 (18.8%) had disease duration <5 years. At 6-12 months post-DBS, median levodopa-equivalent daily dosage (LEDD) reduction was 440.5 [418.9] mg/day, corresponding to a reduction of ≥50% a...
Parkinsonism & Related Disorders
Journal of Movement Disorders
Genetics and Molecular Research, 2012
K.A. Muthusamy et al. glioma patients. Based on this preliminary evidence, the EGF 5'-UTR at posi... more K.A. Muthusamy et al. glioma patients. Based on this preliminary evidence, the EGF 5'-UTR at position 61 and the NAT2 SNP at position 857 polymorphisms are associated with increased risk for glioma.
EThOS - Electronic Theses Online ServiceGBUnited Kingdo
This is a case of an adult patient with hypertensive intraventricular haemorrhages complicated by... more This is a case of an adult patient with hypertensive intraventricular haemorrhages complicated by hydrocephalus that failed to respond to endoscopic third ventriculostomy (ETV). High-resolution 3D Fast Imaging Employing Steady State Acquisition (FIESTA) magnetic resonance imaging (MRI) revealed underlying multiloculated hydrocephalus. This case report highlights the appropriate sequence and its attributes that offer adequate preoperative information detailing the ventricular system.
In this study, we have used EEG data obtained during a reading activity. During the reading proce... more In this study, we have used EEG data obtained during a reading activity. During the reading process, eye saccade and fixation activity are captured using dedicated hardware. We have used the data to show how the onset and progress of eye saccades can be tracked by the presence of high frequency gamma bands in the EEG time-frequency spectra. We also show that this tracking of eye saccades using the gamma bands can be captured by specific independent components of the EEG data. This relationship between saccades and gamma bands suggests caution in correlating gamma bands to cognitive or other neural activit
Journal of Clinical Neuroscience, 2022
INTRODUCTION Tracheostomy is performed in patients with prolonged mechanical ventilation, who suf... more INTRODUCTION Tracheostomy is performed in patients with prolonged mechanical ventilation, who suffered catastrophic neurologic insult or upper airway obstruction. Thus far, there is no consensus on the optimal timing in performing a tracheostomy. This study aims to test whether early tracheostomy in mechanically ventilated patients in a neurosurgical setting would be associated with a shorter time of mechanical ventilation as compared to standard tracheostomy. METHODS This single-center prospective randomized controlled trial was conducted at University Malaya Medical Centre from July 2019 to July 2021. The likelihood of prolonged ventilation was determined objectively using the TRACH score and the patient's clinical presentation. The outcomes measured were days of mechanical ventilation post-tracheostomy, days of neuro-intensive care unit stay, and days of hospital stay. Tracheostomy-related complications were collected. The data collected were analyzed using Statistical Package for the Social Sciences version 25 for Windows (SPSS Inc., Chicago, IL, USA). RESULTS In all, 39 patients were randomly assigned. Of these, 20 were allocated to the early tracheostomy group (ET) and 19 were allocated to the standard tracheostomy group (ST). The demographic characteristics were similar between the groups. The primary outcome, mean (SD) days of mechanical ventilation post-tracheostomy, was statistically different in the 2 groups- early 11.9 (9.3) days, standard 18.9 (32.5) days; p = 0.014. There were comparable tracheostomy-related complications in both groups. CONCLUSION Early tracheostomy is associated with a shorter duration of mechanical ventilation in a neurosurgical intensive care unit setting.
World Neurosurgery, 2019
OBJECTIVES The evaluation of sources of error when preparing, printing and using 3D printed head ... more OBJECTIVES The evaluation of sources of error when preparing, printing and using 3D printed head models for training purposes. METHODOLOGY Two 3D printed models were designed and fabricated using actual patient imaging data with reference-marker points embedded artificially within these models that were then registered to a surgical navigation system using three different methods. The first method uses a conventional manual registration, utilizing the actual patient's imaging data. The second one is done by directly scanning the created model using an intraoperative CT followed by registering the model to a new imaging data set manually. Whilst the third, similar to the second method of scanning the model but eventually using an automatic registration technique. The errors for each experiment were then calculated based on the surgical navigation probe's distance from the embedded marker points position respectively. RESULTS -There were errors found in the preparation and printing techniques largely depending on the orientation of the printed segment and post processing, but these were relatively small. Larger errors were noted based on a couple of variables , that is if the models were registered utilising the original patient imaging data as opposed to using the imaging data from directly scanning the model (1.28mm vs 1.082mm) and the accuracy was best using the automated registration techniques (0.74mm). CONCLUSION Spatial accuracy errors occur consistently in every 3D fabricated model. These errors are derived from the fabrication process, the image registration process as well as the surgical process of registration.
Frontiers in Aging Neuroscience, 2018
The pedunculopontine nucleus (PPN) is situated in the upper pons in the dorsolateral portion of t... more The pedunculopontine nucleus (PPN) is situated in the upper pons in the dorsolateral portion of the ponto-mesencephalic tegmentum. Its main mass is positioned at the trochlear nucleus level, and is part of the mesenphalic locomotor region (MLR) in the upper brainstem. The human PPN is divided into two subnuclei, the pars compacta (PPNc) and pars dissipatus (PPNd), and constitutes both cholinergic and non-cholinergic neurons with afferent and efferent projections to the cerebral cortex, thalamus, basal ganglia (BG), cerebellum, and spinal cord. The BG controls locomotion and posture via GABAergic output of the substantia nigra pars reticulate (SNr). In PD patients, GABAergic BG output levels are abnormally increased, and gait disturbances are produced via abnormal increases in SNr-induced inhibition of the MLR. Since the PPN is vastly connected with the BG and the brainstem, dysfunction within these systems lead to advanced symptomatic progression in Parkinson's disease (PD), including sleep and cognitive issues. To date, the best treatment is to perform deep brain stimulation (DBS) on PD patients as outcomes have shown positive effects in ameliorating the debilitating symptoms of this disease by treating pathological circuitries within the parkinsonian brain. It is therefore important to address the challenges and develop this procedure to improve the quality of life of PD patients.
British Journal of Neurosurgery, 2013
The endoscopic transnasal, transsphenoidal surgical technique for pituitary tumour excision has g... more The endoscopic transnasal, transsphenoidal surgical technique for pituitary tumour excision has generally been regarded as a less invasive technique, ranging from single nostril to dual nostril techniques. We propose a single nostril technique using a modifi ed nasal speculum as a preferred technique. We initially reviewed 25 patients who underwent pituitary tumour excision, via endoscopic transnasal transsphenoidal surgery, using this new modifi ed speculum-guided single nostril technique. The results show shorter operation time with reduced intra-and post-operative nasal soft tissue injuries and complications.
Procedia - Social and Behavioral Sciences, 2013
In this paper, we propose a diffraction based model to explain how coloured filters are able to i... more In this paper, we propose a diffraction based model to explain how coloured filters are able to improve the reading abilities of readers with abnormal eye saccades. We have explained how light of short wavelengths such as blue forms a broader diffraction image compared to light of long wavelength such as red. It is known that blue filters appear to improve reading ability of dyslexics who often present with abnormal eye saccades. Since blue coloured light gives rise to a diffracted image with is broader, it activates both the centrally located parvocellular ganglions as well as the peripherally located magnocellular ganglions. Thus, both pathways formed by these ganglions are activated even if the saccades are abnormal. In the case of red light, since the diffracted image is narrower, the retinal activation region is also narrow matching the narrow retinal region rich in parvocellular ganglions. Images formed in eyes with abnormal saccades will result multiple crossings of a narrow pencil of the diffracted red light beam across the centrally located parvocellular ganglions resulting in a dramatic rise and fall in neural signal in the parvocellular pathway. This causes image instability resulting in unsteady, unclear and distorted images as seen by some poor readers.
Journal of Head Neck & Spine Surgery, Feb 8, 2018
Journal of Neural Transmission
Neurodegenerative Diseases
Pathogenic and risk variants in the LRRK2 gene are among the main genetic contributors to Parkins... more Pathogenic and risk variants in the LRRK2 gene are among the main genetic contributors to Parkinson’s disease (PD) worldwide, and LRRK2-targeted therapies for patients with PARK-LRRK2are now entering clinical trials. However, in contrast to the LRRK2 G2019S mutation commonly found in Caucasians, North-African Arabs, and Ashkenazi Jews, relatively little is known about other causative LRRK2 mutations, and data on genotype-phenotype correlations are largely lacking. This report is from an ongoing multicentre study in which next-generation sequencing-based PD gene panel testing has so far been conducted on 499 PD patients of various ethnicities from Malaysia. We describe 2 sisters of Chinese ancestry with PD who carry the R1441C mutation in LRRK2 (which in Asians has been reported in only 2 Chinese patients previously), and highlight interesting clinical observations made over a decade of close follow-up. We further explored the feasibility of using a brief, expert-administered rating ...
Sleep is an indispensable normal physiology of the human body fundamental for healthy functioning... more Sleep is an indispensable normal physiology of the human body fundamental for healthy functioning. It has been observed that Parkinson's disease (PD) not only exhibits motor symptoms, but also non-motor symptoms such as metabolic irregularities, altered olfaction, cardiovascular dysfunction, gastrointestinal complications and especially sleep disorders which is the focus of this review. A good understanding and knowledge of the different brain structures involved and how they function in the development of sleep disorders should be well comprehended in order to treat and alleviate these symptoms and enhance quality of life for PD patients. Therefore it is vital that the normal functioning of the body in relation to sleep is well understood before proceeding on to the pathophysiology of PD correlating to its symptoms. Suitable treatment can then be administered toward enhancing the quality of life of these patients, perhaps even discovering the cause for this disease.
Frontiers in aging neuroscience, 2016
Sleep is an indispensable normal physiology of the human body fundamental for healthy functioning... more Sleep is an indispensable normal physiology of the human body fundamental for healthy functioning. It has been observed that Parkinson's disease (PD) not only exhibits motor symptoms, but also non-motor symptoms such as metabolic irregularities, altered olfaction, cardiovascular dysfunction, gastrointestinal complications and especially sleep disorders which is the focus of this review. A good understanding and knowledge of the different brain structures involved and how they function in the development of sleep disorders should be well comprehended in order to treat and alleviate these symptoms and enhance quality of life for PD patients. Therefore it is vital that the normal functioning of the body in relation to sleep is well understood before proceeding on to the pathophysiology of PD correlating to its symptoms. Suitable treatment can then be administered toward enhancing the quality of life of these patients, perhaps even discovering the cause for this disease.
Journal of Neurosurgery, Mar 1, 2008
Xanthoma formation is frequently seen over the subcutaneous tissue of extensor surfaces and tendo... more Xanthoma formation is frequently seen over the subcutaneous tissue of extensor surfaces and tendons that have received minor trauma or friction in patients with hypercholesterolemia. However, temporal bone xanthomas with intracranial extension are uncommon. To the best of the authors&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; knowledge, this is the second report in the literature in which bilateral extension of a xanthoma is described. Xanthomas of the temporal bone are benign lesions, and complete or even partial removal is effective. The predisposing cause of the lesion should also be treated.
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Papers by Kalai Muthusamy