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Duchenne muscular dystrophy (DD) is an X-linked disorder, and thus primarily affects males. It is the most common form of muscular dystrophy and has an incidence of 1 in 3,300 male births. Although much effort has been devoted to the identification of carriers, that is, women who carry one copy of the gene and have a 50 percent chance of passing the fatal disorder to a male child, little attention has been given to the small subset of carriers who manifest symptoms of the disease. Seven cases exemplify the Duchenne dystrophy-manifesting carrier (DDMC). All had slow, progressing weakness which began in the second or third decade of life. Three patients had evidence of heart weakness, and all had elevated levels of creatine kinase. The disease takes a relatively benign course in these women. It should be noted that some researchers include among manifesting carriers women who have abnormal laboratory values, but do not exhibit symptoms, a practice which makes comparison with other published reports difficult. Since the seven patients all had histories which included Duchenne dystrophy, the diagnosis was relatively straightforward. However, it would be difficult or impossible to distinguish a carrier from a patient with limb girdle muscular dystrophy in any other way. Limb girdle muscular dystrophy is a autosomal recessive disorder which occurs with about the same frequency as DDMC. Improvements in the application of DNA technology to the identification of DD carriers may reveal further examples of manifesting carriers. It will be interesting to determine if these women also carry a mutation in the autosomal gene involved in limb girdle muscular dystrophy. (Consumer Summary produced by Reliance Medical Information, Inc.)

We investigated the voluntary contraction direction dependence of motor unit number index (MUNIX) for multifunctional muscles in patients with amyotrophic lateral sclerosis (ALS). The MUNIX technique was applied in nine first dorsal interosseous muscles of eight ALS subjects, using surface electromyography (EMG) signals from index finger abduction and flexion, respectively. In seven examined muscles, the MUNIX derived from the index finger abduction mode was smaller than that from the flexion mode. For the remaining two muscles, one had the same MUNIX; the other showed an abduction mode MUNIX much higher than the flexion mode MNUIX. Across all muscles, the median MUNIX was 96 for the index finger abduction mode and 161 for the flexion mode. The findings reveal the dependence of multifunctional muscle MUNIX on voluntary contraction directions in ALS patients. Based on this analysis, we further explored the concept of “multidimensional MUNIX” for an appropriate performance or interpretation of MUNIX in multifunctional muscles of ALS patients. An effort towards such a development was presented using both abduction and flexion mode surface EMG for MUNIX calculation. [ABSTRACT FROM AUTHOR]

Needle electromyogram (EMG) is routinely used in clinical neurophysiology for examination of neuromuscular diseases. This study presents a noninvasive surface EMG method for supporting diagnosis of amyotrophic lateral sclerosis (ALS). Three diagnostic markers including the clustering index, the kurtosis of EMG amplitude histogram, and the kurtosis of EMG crossing-rate expansion, were used respectively to characterize surface EMG patterns recorded during different levels of voluntary muscle contraction. We then applied a linear discriminant analysis classifier to discriminate the ALS subjects from the neurologically intact subjects, using the statistics derived from all the three markers as input feature sets to the classifier. The method was tested in 10 ALS subjects and 11 neurologically intact subjects. Combination of the three surface EMG markers achieved 90% diagnostic sensitivity and 100% diagnostic specificity, which were higher than solely using a single surface EMG marker. Given the high diagnostic yield, the proposed surface EMG analysis can be used as a supplement to needle EMG examination in supporting the diagnosis of ALS. [ABSTRACT FROM AUTHOR]

Background: High-density surface electromyography (HD-SEMG) has recently emerged as a potentially useful tool in the evaluation of amyotrophic lateral sclerosis (ALS). This study addresses a practical constraint that arises when applying HD-SEMG for supporting the diagnosis of ALS; specifically, how long the surface EMG should be recorded before one can be confident that fasciculation potentials (FPs) are absent in a muscle being tested. Methods: HD-SEMG recordings of 29 muscles from 11 ALS patients were analyzed. We used the distribution of intervals between FPs, and estimated the observation duration needed to record from one to five FPs with a probability approaching unity. Such an approach was previously tested by Mills with a concentric needle electrode. Results: We found that the duration of recording was up to 70 s in order to record a single FP with a probability approaching unity. Increasing recording time to 2 minutes, the probability of recording five FPs approached approximately 0.95. Conclusions: HD-SEMG appears to be a suitable method for capturing FPs comparable to intramuscular needle EMG. [ABSTRACT FROM AUTHOR]

AbstractALSUntangled reviews alternate and off-label treatments prompted by patient interest. Here, we review psilocybin, a chemical derived from mushrooms and belonging in the category of drugs known as psychedelics. Psilocybin has plausible mechanisms for slowing ALS progression because of its ability to cross the blood brain barrier and effect neurogenesis and inflammation. Currently, there are no pre-clinical ALS models, case reports, or trials for psilocybin and ALS in the context of disease modifying therapy. Depending on dosing, there can be a high risk of psychological side effects including hallucinations and physical harm. Based on the above information, we do not currently support the use of psilocybin as a means to slow ALS progression. [ABSTRACT FROM AUTHOR]

Introduction/aims: To add objectivity to the routine needle electromyography examination, we describe an "Augmented Intelligence" based interference pattern (IP) analysis method that mimics the subjective assessment by quantifying IP fullness, discreteness, amplitude, pitch, and motor unit firing rate (FR)., Methods: IP recordings from 20 control subjects and other patients with neuropathy and myopathy were analyzed. The IP was divided into three groups: low, intermediate, and full to mimic visual appearance. Reference values (RVs) were defined for each group. "Fence" pattern was defined based on the discreteness and amplitude. Upper limit of FR was defined. Various technical artifacts were detected and excluded from analysis., Results: In control subjects, a total of 2435 recordings from 119 commonly tested muscles were analyzed. The single set of RVs was satisfactory across the tested muscles. Amplitude increased when the pattern changed from low to full. Pitch did not correlate with fullness and its RVs were same for all groups. In patients with neuropathy, an intermediate or low pattern, high amplitude, fence pattern, low pitch, and high FR were demonstrated. In patients with myopathy, a full pattern with low amplitude and high pitch was demonstrated., Discussion: The algorithm makes simple measurements that are readily interpreted by the electromyographer. In this respect, it augments analysis by providing quantitative data. If implemented in an "on-line" manner, it can provide guidance to the operator without adding to the procedure time or changing the recording technique. The measurements can also be included in the report to support the study's findings., (© 2025 Wiley Periodicals LLC.)

Objective: When the compound muscle action potential (CMAP) is recorded in motor nerve conduction studies, the reference (E2) electrode can make a significant contribution to the CMAP. This study investigates the E2 recorded signal and its effect on CMAP measurements when E2 electrode is placed at different sites., Methods: The CMAP was recorded using the active electrode on the muscle belly and 4 different E2 electrodes placed at distal and proximal sites. The signal recorded by each electrode was also measured using a reference electrode on the contralateral limb. Signals were recorded from the abductor pollicis brevis, abductor digiti minimi, tibialis anterior and biceps muscles., Results: The E2 recorded a smaller signal when it was placed near or off the proximal tendon or muscle origin. This affected CMAP latency, duration for tibialis anterior. Contrary to expectation, initial upward deflection was noted for E2 signal., Conclusion: A proximal E2 position records a lower volume conducted signal and yields a CMAP that is more representative of the muscle over which the E1 (active) electrode is placed., Significance: The proposed 'Proximal E2' montage may be better suited to assess pathology., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: The motor unit size index (MUSIX) is incorporated into the motor unit number index (MUNIX). Our objective was to assess the intra-/inter-rater reliability of MUSIX in healthy volunteers across single subject "round robin" and multi-centre settings., Methods: Data were obtained from (i) a round-robin assessment in which 12 raters (6 with prior experience and 6 without) assessed six muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor digitorum brevis and abductor hallucis) and (ii) a multi-centre study with 6 centres studying the same muscles in 66 healthy volunteers. Intra/inter-rater data were provided by 5 centres, 1 centre provided only intra-rater data. Intra/inter-rater variability was assessed using the coefficient of variation (COV), Bland-Altman plots, bias and 95% limits of agreement., Results: In the round-robin assessment intra-rater COVs for MUSIX ranged from 7.8% to 28.4%. Inter-rater variability was between 7.8% and 16.2%. Prior experience did not impact on MUSIX values. In the multi-centre study MUSIX was more consistent than the MUNIX. Abductor hallucis was the least reliable muscle., Conclusions: The MUSIX is a reliable neurophysiological biomarker of reinnervation., Significance: MUSIX could provide insights into the pathophysiology of a range of neuromuscular disorders, providing a quantitative biomarker of reinnervation., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Estimation of the number of motor units (MUNE) in specific muscles is important to monitor outcome in progressive neurogenic disorders, with potential application in clinical trials. However, in spite of recent developments to identify the most convenient technique for MUNE, all current methods have individual shortcomings. It is essential to understand the scientific concepts that support MUNE and the many methods already proposed. In particular, the core role of the compound muscle action potential (CMAP) size in the estimation process is undervalued. Operator-dependent variation in CMAP amplitude or area is the main factor underlying MUNE stability. At present, MUNIX, as standardized in many centers, is probably the best accepted method. Future developments should be based on full understanding of the neurophysiological concepts underlying the MUNE calculation, in order to find a quick, well-tolerated, operator-friendly and reliable method to apply more universally in clinical practice., (Copyright © 2018 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objectives: COL6A and LAMA2 are subtypes of congenital muscular dystrophy., Methods: Retrospective chart review of clinical findings, spirometry, muscle histology, muscle ultrasound, neuroimaging, and Electromyography (EMG)/Nerve Conduction Study data in genetically confirmed COL6A and LAMA2 subjects., Results: We identified 8 COL6A and 6 LAMA2 subjects: the female-to-male ratio was 1.3:1 and the mean age was 11.9 ± 3.6 years. Gross motor delays since birth, proximal muscle weakness, and contractures were noted in both groups. Joint hyperlaxity and skin changes (follicular hyperkeratosis and muscle biopsy scar thinning) were unique to COL6A. Severe scoliosis, macrocephaly, and nonambulatory status were common in LAMA2. Increasing age was associated with poor respiratory function in COL6A. There was central "cloud appearance" on rectus femoris muscle ultrasound in COL6A and white matter T2 hyperintensity on brain magnetic resonance imaging in LAMA2. LAMA2 also showed demyelinating polyneuropathy. Neurogenic changes on EMG and muscle histology were noted in 37% and 33% of COL6A cases, respectively., Conclusions: COL6A has unique skin changes, central cloud appearance on muscle ultrasound. LAMA2 has demyelinating polyneuropathy and white matter changes on brain imaging. The presence of neurogenic changes on EMG and muscle histology in COL6A suggests motor axonal neuropathy. Genetic testing remains the gold standard in confirming COL6A congenital muscular dystrophy.

Introduction: Reference values (RVs) are required to separate normal from abnormal values obtained in electrodiagnostic (EDx) testing. However, it is frequently impractical to perform studies on control subjects to obtain RVs. The Extrapolated Reference Values (E-Ref) procedure extracts RVs from data obtained during clinically indicated EDx testing. We compared the E-Ref results with established RVs in several sets of EDx data., Methods: The mathematical basis for E-Ref was explored to develop an algorithm for the E-Ref procedure. To test the validity of this algorithm, it was applied to simulated and real jitter measurements from control subjects and patients with myasthenia gravis, and to nerve conduction studies from patients with various conditions referred for EDx studies., Results: There was good concordance between E-Ref and RVs for all evaluated data sets., Discussion: E-Ref is a promising method to develop RVs. Muscle Nerve 57: 90-95, 2018., (© 2017 Wiley Periodicals, Inc.)

Objective: Motor Unit Number Index (MUNIX) is a quantitative neurophysiological measure that provides an index of the number of lower motor neurons supplying a muscle. It reflects the loss of motor neurons in patients with Amyotrophic Lateral Sclerosis (ALS). However, it is unclear whether MUNIX also detects motor unit loss in strong, non-wasted muscles., Methods: Three centres measured MUNIX in 49 ALS patients every three months in six different muscles (abductor pollicis brevis, abductor digiti minimi, biceps brachii, tibialis anterior, extensor digitorum brevis, abductor hallucis) on the less affected side. The decline of MUNIX in initially non-wasted, clinically strong muscles (manual muscle testing, MMT grade 5) was analysed before and after onset of weakness., Results: In 49 subjects, 151 clinically strong muscles developed weakness and were included for analysis. The average monthly relative loss of MUNIX was 5.0% before and 5.6% after onset of weakness. This rate of change was significantly higher compared to ALS functional rating scale (ALSFRS-R) and compound muscle action potential (CMAP) change over 12months prior to the onset of muscle weakness (p=0.024)., Conclusion: MUNIX is an electrophysiological marker that detects lower motor neuron loss in ALS, before clinical weakness becomes apparent by manual muscle testing., Significance: This makes MUNIX a good biomarker candidate for disease progression and possibly pharmacodynamics responds., (Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Purpose: To study disease progression in patients with amyotrophic lateral sclerosis (ALS), we have developed the "cumulative motor index (CMI)" using the compound muscle action potential amplitude recorded in multiple upper and lower limb muscles., Methods: To study its reproducibility, CMI was measured by 2 operators in 10 healthy subjects on 2 occasions. In 15 patients with ALS, CMI and ALS functional rating score (revised) were measured at 3- to 6-month interval for 12 months or longer., Results: The CMI had good reproducibility in healthy subjects. In one patient with ALS, CMI and ALS functional rating score (revised) remained relatively unchanged. In all remaining 14 patients with disease progression, CMI decreased in a relatively monotonic manner. At 1 year after baseline study, CMI was reduced more than ALS functional rating score (revised) in 10 patients. CMI measurements were possible for longer time period, than analysis from a single distal muscle recording., Conclusions: The CMI can be measured using standard equipment and software available in most electrodiagnostic laboratories. This may be a simple measurement that can be used for clinical studies of ALS progression over longer time periods.

Background: Fasciculation potentials (FPs) are important in supporting the electrodiagnosis of Amyotrophic Lateral Sclerosis (ALS). If classified by shape, FPs can also be very informative for laboratory-based neurophysiological investigations of the motor units., Methods: This study describes a Matlab program for classification of FPs recorded by multi-channel surface electromyogram (EMG) electrodes. The program applies Principal Component Analysis on a set of features recorded from all channels. Then, it registers unsupervised and supervised classification algorithms to sort the FP samples. Qualitative and quantitative evaluation of the results is provided for the operator to assess the outcome. The algorithm facilitates manual interactive modification of the results. Classification accuracy can be improved progressively until the user is satisfied. The program makes no assumptions regarding the occurrence times of the action potentials, in keeping with the rather sporadic and irregular nature of FP firings., Results: Ten sets of experimental data recorded from subjects with ALS using a 20-channel surface electrode array were tested. A total of 11891 FPs were detected and classified into a total of 235 prototype template waveforms. Evaluation and correction of classification outcome of such a dataset with over 6000 FPs can be achieved within 1-2 days. Facilitated interactive evaluation and modification could expedite the process of gaining accurate final results., Conclusion: The developed Matlab program is an efficient toolbox for classification of FPs., (Published by Elsevier Ltd.)

This study explores a novel application of multiscale entropy (MSE) analysis for characterizing different patterns of spontaneous electromyogram (EMG) signals including sporadic, tonic and repetitive spontaneous motor unit discharges, and normal surface EMG baseline. Two algorithms for MSE analysis, namely, the standard MSE and the intrinsic mode entropy (IMEn) (based on the recently developed multivariate empirical mode decomposition method), were applied to different patterns of spontaneous EMG. Significant differences were observed in multiple scales of the standard MSE and IMEn analyses (<;i>p<;/i> <; 0.001) for any two of the spontaneous EMG patterns, while such significance may not be observed from the single-scale entropy analysis. Compared to the standard MSE, the IMEn analysis facilitates usage of a relatively low scale number to discern entropy difference among various patterns of spontaneous EMG signals. The findings from this study contribute to our understanding of the nonlinear dynamic properties of different spontaneous EMG patterns, which may be related to spinal motoneuron or motor unit health.