Displaying all 14 publications

  1. Kumar SN, Joseph LH, Pharmy Jalil A
    Clin Neurophysiol, 2015 Jul;126(7):1453-4.
    PMID: 25468242 DOI: 10.1016/j.clinph.2014.09.031
  2. 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.
  3. 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.

  4. Dengler R, de Carvalho M, Shahrizaila N, Nodera H, Vucic S, Grimm A, et al.
    Clin Neurophysiol, 2020 07;131(7):1662-1663.
    PMID: 32354605 DOI: 10.1016/j.clinph.2020.03.014
    Modern neuromuscular electrodiagnosis (EDX) and neuromuscular ultrasound (NMUS) require a universal language for effective communication in clinical practice and research and, in particular, for teaching young colleagues. Therefore, the AANEM and the IFCN have decided to publish a joint glossary as they feel the need for an updated terminology to support educational activities in neuromuscular EDX and NMUS in all parts of the world. In addition NMUS has been rapidly progressing over the last years and is now widely used in the diagnosis of disorders of nerve and muscle in conjunction with EDX. This glossary has been developed by experts in the field of neuromuscular EDX and NMUS on behalf of the AANEM and the IFCN and has been agreed upon by electronic communication between January and November 2019. It is based on the glossaries of the AANEM from 2015 and of the IFCN from 1999. The EDX and NMUS terms and the explanatory illustrations have been updated and supplemented where necessary. The result is a comprehensive glossary of terms covering all fields of neuromuscular EDX and NMUS. It serves as a standard reference for clinical practice, education and research worldwide.
  5. Zulkifly MFM, Merkohitaj O, Brockmöller J, Paulus W
    Clin Neurophysiol, 2021 06;132(6):1367-1379.
    PMID: 33762129 DOI: 10.1016/j.clinph.2021.01.024
    OBJECTIVE: We examined the effects of caffeine, time of day, and alertness fluctuation on plasticity effects after transcranial alternating current stimulation (tACS) or 25 ms paired associative stimulation (PAS25) in caffeine-naïve and caffeine-adapted subjects.

    METHODS: In two randomised, double-blinded, cross-over or placebo-controlled (caffeine) studies, we measured sixty subjects in eight sessions (n = 30, Male: Female = 1:1 in each study).

    RESULTS: We found caffeine increased motor cortex excitability in caffeine naïve subjects. The aftereffects in caffeine naïve subjects were enhanced and prolonged when combined with PAS 25. Caffeine also increased alertness and the motor evoked potentials (MEPs) were reduced under light deprivation in caffeine consumers both with and without caffeine. In caffeine consumers, the time of day had no effect on tACS-induced plasticity.

    CONCLUSIONS: We conclude that caffeine should be avoided or controlled as confounding factor for brain stimulation protocols. It is also important to keep the brightness constant in all sessions and study groups should not be mixed with caffeine-naïve and caffeine consuming participants.

    SIGNIFICANCE: Caffeine is one of the confounding factors in the plasticity induction studies and it induces different excitability effects in caffeine-naïve and caffeine-adapted subjects. This study was registered in the ClinicalTrials.gov with these registration IDs: 1) NCT03720665 https://clinicaltrials.gov/ct2/results?cond=NCT03720665&term=&cntry=&state=&city=&dist= 2) NCT04011670 https://clinicaltrials.gov/ct2/results?cond=&term=NCT04011670&cntry=&state=&city=&dist=.

  6. 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.

  7. Rosli Y, Maddess T, Dawel A, James AC
    Clin Neurophysiol, 2009 Dec;120(12):2100-2108.
    PMID: 19846337 DOI: 10.1016/j.clinph.2009.09.006
    OBJECTIVE: To examine the feasibility of a multifocal visual evoked potential (mfVEP) binocularly, using a variant of the multifocal frequency-doubling (FD) pattern-electroretinogram (MFP).

    METHODS: Stimuli were presented in both monocular and dichoptic conditions at eight visual field locations/eye. The incommensurate stimulus frequencies ranged from 15.45 to 21.51 Hz. Five stimulus conditions differing in spatial frequency and orientation were examined for three viewing conditions. The resulting 15 stimulus conditions were examined in 16 normal subjects who repeated all conditions twice.

    RESULTS: Several significant independent effects were identified. Response amplitudes were reduced for dichoptic viewing (by 0.85 times, p<4 x 10(-11)); offset by increases in responses for between eye differences of one octave of spatial frequency: lower (1.15 times, 0.1 cpd); higher (1.29 times, 0.4 cpd), both p<1.8 x 10(-7). Crossed orientations produced significant effects upon response phase (p=0.023) but not amplitude (p=0.062).

    CONCLUSIONS: The results indicated that dichoptic evoked potentials using multifocal frequency-doubling illusion stimuli are practical. The use of crossed orientation, or differing spatial frequencies, in the two eyes reduced binocular interactions.

    SIGNIFICANCE: The results indicate a method wherein several spatial or temporal and frequencies per visual field region can be tested in reasonable time using a multifocal VEP using spatial frequency-doubling stimuli.

  8. 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.

  9. 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.

  10. Habib MA, Ibrahim F, Mohktar MS, Kamaruzzaman SB, Lim KS
    Clin Neurophysiol, 2020 03;131(3):642-654.
    PMID: 31978849 DOI: 10.1016/j.clinph.2019.11.058
    OBJECTIVE: This study aimed to present a new ictal component selection technique, named as recursive ICA-decomposition for ictal component selection (RIDICS), for potential application in epileptogenic zone localization.

    METHODS: The proposed technique decomposes ictal EEG recursively, eliminates a few unwanted components in every recursive cycle, and finally selects the most significant ictal component. Back-projected EEG, regenerated from that component, was used for source estimation. Fifty sets of simulated EEGs and 24 seizures in 8 patients were analyzed. Dipole sources of simulated-EEGs were compared with a known dipole location whereas epileptogenic zones of the seizures were compared with their corresponding sites of successful surgery. The RIDICS technique was compared with a conventional technique.

    RESULTS: The RIDICS technique estimated the dipole sources at an average distance of 12.86 mm from the original dipole location, shorter than the distances obtained using the conventional technique. Epileptogenic zones of the patients, determined by the RIDICS technique, were highly concordant with the sites of surgery with a concordance rate of 83.33%.

    CONCLUSIONS: Results show that the RIDICS technique can be a promising quantitative technique for ictal component selection.

    SIGNIFICANCE: Properly selected ictal component gives good approximation of epileptogenic zone, which eventually leads to successful epilepsy surgery.

  11. Toh TH, Abdul-Aziz NA, Yahya MA, Goh KJ, Loh EC, Capelle DP, et al.
    Clin Neurophysiol, 2021 10;132(10):2722-2728.
    PMID: 34312065 DOI: 10.1016/j.clinph.2021.05.034
    OBJECTIVE: We aimed to develop a model to predict amyotrophic lateral sclerosis (ALS) disease progression based on clinical and neuromuscular ultrasound (NMUS) parameters.

    METHODS: ALS patients were prospectively recruited. Muscle fasciculation (≥2 over 30-seconds, examined in biceps brachii-brachialis (BB), brachioradialis, tibialis anterior and vastus medialis) and nerve cross-sectional area (CSA) (median, ulnar, tibial, fibular nerve) were evaluated through NMUS. Ultrasound parameters were correlated with clinical data, including revised ALS Functional Rating Scale (ALSFRS-R) progression at one year. A predictive model was constructed to differentiate fast progressors (ALSFRS-R decline ≥ 1/month) from non-fast progressors.

    RESULTS: 40 ALS patients were recruited. Three parameters emerged as strong predictors of fast progressors: (i) ALSFRS-R slope at time of NMUS (p = 0.041), (ii) BB fasciculation count (p = 0.027) and (iii) proximal to distal median nerve CSA ratio 

  12. Arends S, Drenthen J, van den Bergh P, Franssen H, Hadden RDM, Islam B, et al.
    Clin Neurophysiol, 2022 Jun;138:231-240.
    PMID: 35078730 DOI: 10.1016/j.clinph.2021.12.014
    OBJECTIVE: To describe the heterogeneity of electrodiagnostic (EDx) studies in Guillain-Barré syndrome (GBS) patients collected as part of the International GBS Outcome Study (IGOS).

    METHODS: Prospectively collected clinical and EDx data were available in 957 IGOS patients from 115 centers. Only the first EDx study was included in the current analysis.

    RESULTS: Median timing of the EDx study was 7 days (interquartile range 4-11) from symptom onset. Methodology varied between centers, countries and regions. Reference values from the responding 103 centers were derived locally in 49%, from publications in 37% and from a combination of these in the remaining 15%. Amplitude measurement in the EDx studies (baseline-to-peak or peak-to-peak) differed from the way this was done in the reference values, in 22% of motor and 39% of sensory conduction. There was marked variability in both motor and sensory reference values, although only a few outliers accounted for this.

    CONCLUSIONS: Our study showed extensive variation in the clinical practice of EDx in GBS patients among IGOS centers across the regions.

    SIGNIFICANCE: Besides EDx variation in GBS patients participating in IGOS, this diversity is likely to be present in other neuromuscular disorders and centers. This underlines the need for standardization of EDx in future multinational GBS studies.

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