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  1. Shahrizaila N, Goh KJ, Kokubun N, Tan AH, Tan CY, Yuki N
    Muscle Nerve, 2014 Apr;49(4):558-63.
    PMID: 23893512 DOI: 10.1002/mus.23973
    Differing patterns of neurophysiological abnormalities have been reported in patients with Fisher syndrome. Fisher syndrome is rare, and few series have incorporated prospective serial studies to define the natural history of nerve conduction studies in Guillain-Barré syndrome.
    Matched MeSH terms: Neural Conduction/physiology*
  2. Buschbacher RM, Weir SK, Bentley JG, Cottrell E
    PM R, 2009 Feb;1(2):101-6.
    PMID: 19627883 DOI: 10.1016/j.pmrj.2008.08.002
    Proximal peripheral nerve conduction studies can provide useful information to the clinician. The difficulty of measuring the length of the proximal nerve as well as a frequent inability to stimulate at 2 points along the nerve adds a challenge to the use of electrodiagnosis for this purpose. The purpose of this article is to present normal values for the suprascapular, axillary, and musculocutaneous nerves using surface electrodes while accounting for side-to-side variability.
    Matched MeSH terms: Neural Conduction/physiology*
  3. Fong SY, Goh KJ, Shahrizaila N, Wong KT, Tan CT
    Muscle Nerve, 2016 08;54(2):244-8.
    PMID: 26790132 DOI: 10.1002/mus.25029
    INTRODUCTION: We investigated the effects of demographic and physical factors on nerve conduction studies (NCS) in a multi-ethnic Asian population.

    METHODS: One hundred sixty-six healthy Malaysians of different ethnicities (51.2% women, aged 21-77 years) underwent NCS using a standard protocol. Correlations of various factors to NCS were determined, and multiple linear regression analysis was used to develop predictive equations for each parameter.

    RESULTS: Age and ethnicity were the commonest independent factors influencing NCS followed by gender, height, weight, and body mass index. Increasing age predicted a reduction in lower limb motor and all sensory nerve action potential amplitudes and decrease in motor and sensory (except sural) conduction velocities. Ethnic Indians had slower motor and sensory conduction velocities in several nerves and also had differences in action potential amplitudes.

    CONCLUSIONS: NCS parameters in multi-ethnic Malaysians were influenced independently by various demographic and physical factors, including ethnicity. Muscle Nerve 54: 244-248, 2016.

    Matched MeSH terms: Neural Conduction/physiology*
  4. Razali SNO, Arumugam T, Yuki N, Rozalli FI, Goh KJ, Shahrizaila N
    Clin Neurophysiol, 2016 Feb;127(2):1652-1656.
    PMID: 26228791 DOI: 10.1016/j.clinph.2015.06.030
    OBJECTIVE: To assess the longitudinal changes of nerve ultrasound in Guillain-Barré syndrome (GBS) patients.

    METHODS: We prospectively recruited 17 GBS patients and 17 age and gender-matched controls. Serial studies of their nerve conduction parameters and nerve ultrasound, documenting the cross-sectional areas (CSA), were performed at admission and repeated at several time points throughout disease course.

    RESULTS: Serial nerve ultrasound revealed significantly enlarged CSA in median, ulnar and sural nerves within the first 3 weeks of disease onset. Longitudinal evaluation revealed an improvement in the nerve CSA with time, reaching significance in the ulnar and sural nerves after 12 weeks. There was no significant difference between the demyelinating and axonal subtypes. There was also no significant correlation found between nerve CSA and neurophysiological parameters or changes in nerve CSA and muscle strength.

    CONCLUSION: In GBS, serial studies of peripheral nerve ultrasound CSA are helpful to detect a gradual improvement in the nerve size.

    SIGNIFICANCE: Serial nerve ultrasound studies could serve as a useful tool in demonstrating nerve recovery in GBS.

    Matched MeSH terms: Neural Conduction/physiology*
  5. Uncini A, Ippoliti L, Shahrizaila N, Sekiguchi Y, Kuwabara S
    Clin Neurophysiol, 2017 07;128(7):1176-1183.
    PMID: 28521265 DOI: 10.1016/j.clinph.2017.03.048
    OBJECTIVE: To optimize the electrodiagnosis of Guillain-Barré syndrome (GBS) subtypes at first study.

    METHODS: The reference electrodiagnosis was obtained in 53 demyelinating and 45 axonal GBS patients on the basis of two serial studies and results of anti-ganglioside antibodies assay. We retrospectively employed sparse linear discriminant analysis (LDA), two existing electrodiagnostic criteria sets (Hadden et al., 1998; Rajabally et al., 2015) and one we propose that additionally evaluates duration of motor responses, sural sparing pattern and defines reversible conduction failure (RCF) in motor and sensory nerves at second study.

    RESULTS: At first study the misclassification error rates, compared to reference diagnoses, were: 15.3% for sparse LDA, 30% for our criteria, 45% for Rajabally's and 48% for Hadden's. Sparse LDA identified seven most powerful electrophysiological variables differentiating demyelinating and axonal subtypes and assigned to each patient the diagnostic probability of belonging to either subtype. At second study 46.6% of axonal GBS patients showed RCF in two motor and 8.8% in two sensory nerves.

    CONCLUSIONS: Based on a single study, sparse LDA showed the highest diagnostic accuracy. RCF is present in a considerable percentage of axonal patients.

    SIGNIFICANCE: Sparse LDA, a supervised statistical method of classification, should be introduced in the electrodiagnostic practice.

    Matched MeSH terms: Neural Conduction/physiology
  6. Poznanski RR, Cacha LA, Al-Wesabi YMS, Ali J, Bahadoran M, Yupapin PP, et al.
    Sci Rep, 2017 05 31;7(1):2746.
    PMID: 28566682 DOI: 10.1038/s41598-017-01849-3
    A model of solitonic conduction in neuronal branchlets with microstructure is presented. The application of cable theory to neurons with microstructure results in a nonlinear cable equation that is solved using a direct method to obtain analytical approximations of traveling wave solutions. It is shown that a linear superposition of two oppositely directed traveling waves demonstrate solitonic interaction: colliding waves can penetrate through each other, and continue fully intact as the exact pulses that entered the collision. These findings indicate that microstructure when polarized can sustain solitary waves that propagate at a constant velocity without attenuation or distortion in the absence of synaptic transmission. Solitonic conduction in a neuronal branchlet arising from polarizability of its microstructure is a novel signaling mode of electrotonic signals in thin processes (<0.5 μm diameter).
    Matched MeSH terms: Neural Conduction/physiology*
  7. Shahrizaila N, Noto Y, Simon NG, Huynh W, Shibuya K, Matamala JM, et al.
    Clin Neurophysiol, 2017 Jan;128(1):227-232.
    PMID: 27940147 DOI: 10.1016/j.clinph.2016.11.010
    OBJECTIVE: The utility of quantitative muscle ultrasound as a marker of disease severity in Charcot-Marie-Tooth (CMT) disease subtypes was investigated.

    METHODS: Muscle ultrasound was prospectively performed on 252 individual muscles from 21 CMT patients (9 CMT1A, 8 CMTX1, 4 CMT2A) and compared to 120 muscles from 10 age and gender-matched controls. Muscle ultrasound recorded echogenicity and thickness in representative muscles including first dorsal interosseus (FDI) and tibialis anterior (TA).

    RESULTS: Muscle volume of FDI and thickness of TA correlated with MRC strength. Muscle echogenicity was significantly increased in FDI (65.05 vs 47.09; p<0.0001) and TA (89.45 vs 66.30; p<0.0001) of CMT patients. In TA, there was significantly higher muscle thickness (23 vs 18 vs 16mm; p<0.0001) and lower muscle echogenicity (80 vs 95 vs 108; p<0.0001) in CMT1A compared to CMTX1 and CMT2A. This corresponded to disease severity based on muscle strength (MRC grading CMT1A vs CMTX1 vs CMT2A: 59 vs 48 vs 44; p=0.002).

    CONCLUSION: In CMT, quantitative muscle ultrasound of FDI and TA is a useful marker of disease severity.

    SIGNIFICANCE: The current findings suggest that quantitative muscle ultrasound has potential as a surrogate marker of disease progression in future interventional trials in CMT.

    Matched MeSH terms: Neural Conduction/physiology
  8. Shahrizaila N, Kokubun N, Sawai S, Umapathi T, Chan YC, Kuwabara S, et al.
    Neurology, 2014 Jul 8;83(2):118-24.
    PMID: 24920848 DOI: 10.1212/WNL.0000000000000577
    To comprehensively investigate the relationship between antibodies to single glycolipids and their complexes and Guillain-Barré syndrome subtypes and clinical features.
    Matched MeSH terms: Neural Conduction/physiology
  9. Shahrizaila N, Goh KJ, Kokubun N, Abdullah S, Yuki N
    J Neurol Sci, 2011 Oct 15;309(1-2):26-30.
    PMID: 21849173 DOI: 10.1016/j.jns.2011.07.042
    The electrodiagnosis of Guillain-Barré syndrome (GBS) can be broadly divided into acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). Fisher syndrome (FS) is a variant of GBS, although the underlying neuropathy of FS has yet to be established. Serial nerve conduction studies (NCS) can provide further insight into the likely pathophysiology by further subtyping of GBS and FS. We present a patient with an initial diagnosis of AIDP in whom repeated NCS revealed the AMAN variant. This led us to investigate serial NCS in five patients with GBS, FS and FS/GBS overlap presenting over a period of a year. Three patients with AIDP showed a gradual increase in distal motor latencies during the acute phase of illness. NCS of two patients with FS and FS/GBS overlap showed no demyelinating features suggesting underlying axonal neuropathy in this group of patients. The importance of serial NCS in establishing the underlying pattern of neuropathy in GBS and FS is further emphasized in this study. Larger studies incorporating serial NCS are required to confirm the observations seen in our case series especially when pathological studies are often not justified in this group of patients.
    Matched MeSH terms: Neural Conduction/physiology*
  10. Prakash KM, Raymond AA
    Med J Malaysia, 2003 Mar;58(1):69-78.
    PMID: 14556328
    Bell's palsy is a common neurological problem causing considerable loss of self-esteem among patients. A prospective observational study was conducted to determine the short-term outcome of Bell's palsy at 1 month and 2 months after the onset and the relationship between these outcomes with facial nerve degeneration. We also determined if gender, age, diabetes, systolic and diastolic blood pressure influence the severity of facial nerve degeneration and the clinical outcome at 2 months after the onset. After clinically grading the newly diagnosed unilateral Bell's palsy patients using the House-Brackmann facial nerve grading system, nerve conduction studies of the facial nerve were done to determine the severity of facial nerve degeneration. The recovery of the facial paralysis was clinically graded again at the end of 1 month and 2 months from the onset. A total of 37 patients were recruited. There was a strong positive correlation between facial nerve degeneration and the clinical outcome of Bell's palsy at 1 month (r = 0.794; p < 0.0005) and 2 months (r = 0.732; p < 0.0005) after the onset. There was no significant correlation between either the facial nerve degeneration or the clinical outcome at 2 months with the patients' age (p = 0.288 and p = 0.799 respectively), systolic blood pressure (p = 0.425 and p = 0.933 respectively) or diastolic blood pressure (p = 0.243 and p = 0.579 respectively). Neither the severity of facial nerve degeneration nor the clinical outcome at 2 months were significantly different between male and female patients (p = 0.460 and p = 0.725 respectively) or diabetic and non-diabetic patients (p = 0.655 and p = 0.655 respectively).
    Matched MeSH terms: Neural Conduction/physiology*
  11. Chan YC, Punzalan-Sotelo AM, Kannan TA, Shahrizaila N, Umapathi T, Goh EJH, et al.
    Muscle Nerve, 2017 Nov;56(5):919-924.
    PMID: 28093784 DOI: 10.1002/mus.25577
    INTRODUCTION: In this study we propose electrodiagnostic criteria for early reversible conduction failure (ERCF) in axonal Guillain-Barré syndrome (GBS) and apply them to a cohort of GBS patients.

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

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

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

    Matched MeSH terms: Neural Conduction/physiology*
  12. Ong TL, Goh KJ, Shahrizaila N, Wong KT, Tan CY
    Neurol India, 2019 12 21;67(6):1532-1535.
    PMID: 31857554 DOI: 10.4103/0028-3886.273621
    Distal acquired demyelinating symmetric neuropathy (DADS) is a variant of chronic inflammatory demyelinating polyneuropathy (CIDP) characterized by symmetrical, distal, sensory or sensorimotor involvement. DADS with M-protein (DADS-M) is less responsive to immunotherapy compared to those without M-protein (DADS-I). We report a case of DADS-I with severe clinical presentation viz. early hand involvement with marked wasting, inexcitable peripheral nerves on neurophysiology and poor response to immunotherapy. Despite the unusual presentation, ancillary tests including cerebrospinal fluid analysis, nerve biopsy and nerve ultrasound were supportive of an inflammatory demyelinating polyneuropathy. This case demonstrated the heterogeneity of the disorder and expands the clinical spectrum of DADS neuropathy.
    Matched MeSH terms: Neural Conduction/physiology
  13. Lubis SH, El Sersi M, Hussein SH, Sakian NI, Salleh R, Rafai J, et al.
    Asia Pac J Public Health, 2008 Oct;20 Suppl:162-5.
    PMID: 19533876
    A cross sectional study was conducted to investigate the effects of pesticide exposure (organophosphate and carbamate) using nerve conductive velocity, current perception threshold (CPT). Cluster random sampling was employed to recruit 64 paddy farmers and 22 fishermen in June 2006. The duration of pesticide exposure was between (5-20) years. The CPT values were measured using Neurometer CPT/Eagle, on the index finger and the great toe with three neuroselective frequencies range (2000, 250, and 5 Hz). The results showed that at the three different frequencies, the CPT values were significantly elevated among farmers on both the medial and peroneal nerves (P < .002). The measurement of CPT can be used as a biomarker to determine and monitor the effects of organophosphate and carbamate exposure among workers who may have been exposed.
    Matched MeSH terms: Neural Conduction/physiology
  14. Awang MS, Abdullah JM, Abdullah MR, Tahir A, Tharakan J, Prasad A, et al.
    Med. Sci. Monit., 2007 Jul;13(7):CR330-2.
    PMID: 17599028
    Nerve conduction study is essential in the diagnosis of focal neuropathies and diffuse polyneuropathies. There are many factors that can affect nerve conduction velocity, and age is one of them. Most of the many studies of this effect, and the values from them, were on Caucasian subjects. Therefore, this study was designed to investigate the effect of age on conduction velocity among healthy Asian Malay subjects by analyzing its influence on the median, ulnar, and sural nerves.
    Matched MeSH terms: Neural Conduction/physiology*
  15. Shahrizaila N, Goh KJ, Abdullah S, Kuppusamy R, Yuki N
    Clin Neurophysiol, 2013 Jul;124(7):1456-9.
    PMID: 23395599 DOI: 10.1016/j.clinph.2012.12.047
    Recent studies have advocated the use of serial nerve conduction studies (NCS) in the electrodiagnosis of Guillain-Barré syndrome (GBS). The current study aims to elucidate when and how frequent NCS can be performed to reflect the disease pathophysiology.
    Matched MeSH terms: Neural Conduction/physiology*
  16. Tan CY, Razali SNO, Goh KJ, Shahrizaila N
    J Peripher Nerv Syst, 2020 09;25(3):256-264.
    PMID: 32511817 DOI: 10.1111/jns.12398
    We aimed to evaluate the key diagnostic features of Guillain-Barré syndrome (GBS) in Malaysian patients and validate the Brighton criteria. This was a retrospective study of patients presenting with GBS and Miller Fisher syndrome (MFS) between 2010 and 2019. The sensitivity of the Brighton criteria was evaluated. A total of 128 patients (95 GBS, 33 MFS) were included. In the GBS cohort, 92 (97%) patients presented with symmetrical limb weakness. Reflexes were depressed or absent in 90 (95%) patients. Almost all patients (94, 99%) followed a monophasic disease course, with 5 (5%) patients experiencing treatment-related fluctuations. Cerebrospinal fluid (CSF) albuminocytological dissociation was seen in 62/84 (73%) patients. Nerve conduction study (NCS) revealed neuropathy in 90/94 (96%) patients. In GBS patients with complete dataset (84), 56 (67%) patients reached level 1 of the Brighton criteria, 21 (25%) reached level 2, 3 (4%) reached level 3, and 4 (5%) reached level 4. In MFS, the clinical triad was present in 25 (76%) patients. All patients had a monophasic course. CSF albuminocytological dissociation was present in 10/25 (40%) patients. NCS was normal or showed sensory neuropathy in 25/33 (76%) patients. In MFS patients with complete dataset (25), 5 (20%) patients reached level 1 of the Brighton criteria, 14 (56%) reached level 2, 2 (8%) reached level 3, and 4 (16%) reached level 4. Inclusion of antiganglioside antibodies improved the sensitivity of the Brighton criteria in both cohorts. In the Malaysian cohort, the Brighton criteria showed a moderate to high sensitivity in reaching the highest diagnostic certainty of GBS, but the sensitivity was lower in MFS.
    Matched MeSH terms: Neural Conduction/physiology
  17. Tan CY, Sekiguchi Y, Goh KJ, Kuwabara S, Shahrizaila N
    Clin Neurophysiol, 2020 01;131(1):63-69.
    PMID: 31751842 DOI: 10.1016/j.clinph.2019.09.025
    OBJECTIVE: We aimed to develop a model that can predict the probabilities of acute inflammatory demyelinating polyneuropathy (AIDP) based on nerve conduction studies (NCS) done within eight weeks.

    METHODS: The derivation cohort included 90 Malaysian GBS patients with two sets of NCS performed early (1-20days) and late (3-8 weeks). Potential predictors of AIDP were considered in univariate and multivariate logistic regression models to develop a predictive model. The model was externally validated in 102 Japanese GBS patients.

    RESULTS: Median motor conduction velocity (MCV), ulnar distal motor latency (DML) and abnormal ulnar/normal sural pattern were independently associated with AIDP at both timepoints (median MCV: p = 0.038, p = 0.014; ulnar DML: p = 0.002, p = 0.003; sural sparing: p = 0.033, p = 0.009). There was good discrimination of AIDP (area under the curve (AUC) 0.86-0.89) and this was valid in the validation cohort (AUC 0.74-0.94). Scores ranged from 0 to 6, and corresponded to AIDP probabilities of 15-98% at early NCS and 6-100% at late NCS.

    CONCLUSION: The probabilities of AIDP could be reliably predicted based on median MCV, ulnar DML and ulnar/sural sparing pattern that were determined at early and late stages of GBS.

    SIGNIFICANCE: A simple and valid model was developed which can accurately predict the probability of AIDP.

    Matched MeSH terms: Neural Conduction/physiology*
  18. Raja J, Balaikerisnan T, Ramanaidu LP, Goh KJ
    Int J Rheum Dis, 2021 Mar;24(3):347-354.
    PMID: 33432774 DOI: 10.1111/1756-185X.14042
    AIM: The reported prevalence of peripheral neuropathy in systemic sclerosis (SSc) is variable between 0.01% to 28%, probably due to differences in sample size, study design and population. Our aim is to determine the prevalence of large fiber peripheral neuropathy in SSc and to identify any contributing factors.

    METHOD: A prospective cross-sectional study of 60 SSc patients were evaluated for large fiber neuropathy using the modified clinical Total Neuropathy Score (cTNS) and nerve conduction study (NCS) of the upper and lower limbs. A combination of clinical (cTNS score ≥ 2) and NCS criteria (≥2 abnormal nerves including 1 sural [symmetrical polyneuropathy] and NCS abnormalities consistent with individual nerves/nerve roots [focal neuropathy]) was used to diagnose peripheral neuropathy.

    RESULTS: The majority had limited cutaneous subset (75%). Mean age was 55.73 (SD ± 13.04) years and mean disease duration was 8.61 (SD ± 8.09) years. Twenty-two (36.7%) had combined clinical and NCS criteria for peripheral neuropathy, 14 (23.3%) with symmetrical polyneuropathy and 8 (13.3%) with focal neuropathy. Symmetrical polyneuropathy patients had significantly lower hemoglobin levels (11.2 vs. 12.35 g/L; P = .047). Serum vitamin B12 levels were normal, therefore excluding vitamin B12 deficiency. No other associations were found for both polyneuropathy and focal neuropathy with demography, co-morbid diseases and SSc disease factors such as Raynaud's phenomenon and modified Rodnan skin score.

    CONCLUSION: Large fiber neuropathy is common in SSc patients, which could contribute to non-lethal burden in SSc with sensory loss and muscle weakness. Apart from lower hemoglobin in polyneuropathy, there were no associations with disease-specific features or co-morbid diseases.

    Matched MeSH terms: Neural Conduction/physiology*
  19. Bala U, Leong MP, Lim CL, Shahar HK, Othman F, Lai MI, et al.
    PLoS One, 2018;13(5):e0197711.
    PMID: 29795634 DOI: 10.1371/journal.pone.0197711
    BACKGROUND: Down syndrome (DS) is a genetic disorder caused by presence of extra copy of human chromosome 21. It is characterised by several clinical phenotypes. Motor dysfunction due to hypotonia is commonly seen in individuals with DS and its etiology is yet unknown. Ts1Cje, which has a partial trisomy (Mmu16) homologous to Hsa21, is well reported to exhibit various typical neuropathological features seen in individuals with DS. This study investigated the role of skeletal muscles and peripheral nerve defects in contributing to muscle weakness in Ts1Cje mice.

    RESULTS: Assessment of the motor performance showed that, the forelimb grip strength was significantly (P<0.0001) greater in the WT mice compared to Ts1Cje mice regardless of gender. The average survival time of the WT mice during the hanging wire test was significantly (P<0.0001) greater compared to the Ts1Cje mice. Also, the WT mice performed significantly (P<0.05) better than the Ts1Cje mice in the latency to maintain a coordinated motor movement against the rotating rod. Adult Ts1Cje mice exhibited significantly (P<0.001) lower nerve conduction velocity compared with their aged matched WT mice. Further analysis showed a significantly (P<0.001) higher population of type I fibres in WT compared to Ts1Cje mice. Also, there was significantly (P<0.01) higher population of COX deficient fibres in Ts1Cje mice. Expression of Myf5 was significantly (P<0.05) reduced in triceps of Ts1Cje mice while MyoD expression was significantly (P<0.05) increased in quadriceps of Ts1Cje mice.

    CONCLUSION: Ts1Cje mice exhibited weaker muscle strength. The lower population of the type I fibres and higher population of COX deficient fibres in Ts1Cje mice may contribute to the muscle weakness seen in this mouse model for DS.

    Matched MeSH terms: Neural Conduction/physiology*
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