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.
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.
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.
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.
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.
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.
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.
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.