The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Michael Swash - One of the best experts on this subject based on the ideXlab platform.
-
Sensory modulation of Fasciculation discharge frequency.
Muscle & Nerve, 2019Co-Authors: Mamede De Carvalho, Antónia Turkman, Michael SwashAbstract:INTRODUCTION Fasciculations are a marker for the diagnosis of amyotrophic lateral sclerosis (ALS) and reflect increased lower motor neuron (LMN) excitability. METHODS We investigated modulation of Fasciculation frequency in the first dorsal interosseous (FDI) muscle of the right hand following peripheral sensory nerve electrical stimulation, and vibration over the muscle-tendon region (50 and 100 Hz), in patients with ALS, spinal muscular atrophy, and benign Fasciculation syndrome. FDI muscles of ALS patients were classified by the presence or absence of neurogenic changes on needle electromyography. RESULTS Both sensory nerve electrical stimulation and vibration significantly increased the frequency of Fasciculations in neurogenic FDI muscles of ALS patients, but not in the remaining groups. DISCUSSION Our results favour increased excitability of LMNs when affected by the disease process in ALS. We found that some Fasciculations originating in these neurons in ALS are susceptible to modulation by sensory input. Muscle Nerve 59:688-693, 2019.
-
Fasciculation in amyotrophic lateral sclerosis: origin and pathophysiological relevance.
Journal of Neurology Neurosurgery and Psychiatry, 2017Co-Authors: Mamede De Carvalho, Matthew C. Kiernan, Michael SwashAbstract:This review considers the origin and significance of Fasciculations in neurological practice, with an emphasis on Fasciculations in amyotrophic lateral sclerosis (ALS), and in benign Fasciculation syndromes. Fasciculation represents a brief spontaneous contraction that affects a small number of muscle fibres, causing a flicker of movement under the skin. While an understanding of the role of Fasciculation in ALS remains incomplete, Fasciculations derive from ectopic activity generated in the motor system. A proximal origin seems likely to contribute to the generation of Fasciculation in the early stages of ALS, while distal sites of origin become more prominent later in the disease, associated with distal motor axonal sprouting as part of the reinnervation response that develops secondary to loss of motor neurons. Fasciculations are distinct from the recurrent trains of axonal firing described in neuromyotonia. Fasciculation without weakness, muscle atrophy or increased tendon reflexes suggests a benign Fasciculation syndrome, even when of sudden onset. Regardless of origin, Fasciculations often present as the initial abnormality in ALS, an early harbinger of dysfunction and aberrant firing of motor neurons.
-
Fasciculation discharge frequency in amyotrophic lateral sclerosis and related disorders
Clinical Neurophysiology, 2016Co-Authors: Mamede De Carvalho, Michael SwashAbstract:Abstract Objective In amyotrophic lateral sclerosis (ALS), Fasciculations are believed to become less frequent during disease progression, associated with the loss of motor units. To address this issue, we studied the variation of Fasciculation potential (FPs) frequency as evaluated by surface electromyography of the first dorsal interosseous muscle (1st DI) in patients with ALS and other related disorders, and to relate this change with the neurophysiological index (NI), a surrogate measure of functional motor units. Methods We measured the FP frequency and mean amplitude during a two minute recording of the relaxed right first dorsal interosseous muscle (1st DI) in 34 ALS patients, 9 subjects with benign Fasciculations (BFS), 6 with primary lateral sclerosis (PLS) and 4 with spinal muscle atrophy (SMA). ALS patients were evaluated 2–5times at 4month intervals, people with BFS were evaluated 3–4 times at the same interval, those with SMA and PLS were evaluated at 6month intervals 2–4times. The NI was derived from the amplitude of the motor response and F-wave frequency after distal ulnar nerve stimulation. Results The NI decreased significantly in ALS ( p Conclusion In ALS, the generators of FPs remain active even when the number of motor units is quite reduced, consistent with increased motoneuron excitability associated with unstable axonal sprouts during the process of continuous partial reinnervation. In BFS and other neuromuscular disorders, including SMA, the FP frequency is stable over time, suggesting mature motor axons that are not hyperexcitable and less prone to ectopic activity. Significance In ALS, the FP firing frequency does not decline significantly over several months, in spite of a marked reduction in the number of functional motor units.
-
Origin of Fasciculations in root lesions.
Clinical Neurophysiology, 2015Co-Authors: Mamede De Carvalho, Michael SwashAbstract:Abstract Objective Fasciculations are occasionally observed in root lesions, but their site of origin is uncertain. Methods We studied the origin of Fasciculations (FPs) in consecutive patients with mild chronic L5 root lesions, excluding peripheral nerve lesion. We used a novel technique of double-EMG needle recording, in which each needle was placed in the territory of separate motor units. With this technique the observation of synchronous FPs implies an origin proximal to distal axonal branching. Results FPs were found in 13% of 84 consecutive patients with mild chronic L5 root lesions. In 25% they were synchronous in different motor units. Conclusions We suggest that in mild L5 root lesions most FPs have an origin at distal branches but some FPs originate proximally (25%), possibly at the site of nerve compression. Significance The proximal site of compression and more distal sites may both initiate Fasciculation potentials in proximal root lesions.
-
modulation of Fasciculation frequency in amyotrophic lateral sclerosis
Journal of Neurology Neurosurgery and Psychiatry, 2015Co-Authors: Mamede De Carvalho, Michael Swash, Antónia Turkman, Susana PintoAbstract:Fasciculations are a major clinical feature, present very early in the natural history of amyotrophic lateral sclerosis (ALS).1 They represent spontaneous discharges of motor units or portions of motor units, that can sometimes also be activated volitionally.2 There is no objective evidence that Fasciculation potential (FP) discharges can be modulated by the patient or by the examiner. In this study we have addressed this issue in ALS, spinal muscular atrophy (SMA) and benign Fasciculation syndrome (BFS). We evaluated Fasciculation firing frequency, using surface electromyographic (EMG) recordings from the first dorsal interosseous (DI) muscle in the hand at rest, and randomly after a period of maximal contraction, thus involving upper and lower motor neuron excitation, after radial sensory nerve stimulation and after supramaximal electrical stimulation of the ulnar nerve at the wrist, representing lower motor neuron excitation. We studied 75 patients with definite or probable ALS, excluding patients with polyneuropathy, diabetes or ulnar neuropathy (median age 61 years (range 27–75 years), median disease duration 12 months (range 3–24 months), 48 were men). One hand, in which first DI strength was 4 on the MRC (Medical Research Council) score 4 or 5, was studied in each patient. In each participant, FPs were recorded at rest in the first DI muscle. Six patients with SMA type 3 were studied (median age 45 years; range 28–60 years). …
Mamede De Carvalho - One of the best experts on this subject based on the ideXlab platform.
-
Sensory modulation of Fasciculation discharge frequency.
Muscle & Nerve, 2019Co-Authors: Mamede De Carvalho, Antónia Turkman, Michael SwashAbstract:INTRODUCTION Fasciculations are a marker for the diagnosis of amyotrophic lateral sclerosis (ALS) and reflect increased lower motor neuron (LMN) excitability. METHODS We investigated modulation of Fasciculation frequency in the first dorsal interosseous (FDI) muscle of the right hand following peripheral sensory nerve electrical stimulation, and vibration over the muscle-tendon region (50 and 100 Hz), in patients with ALS, spinal muscular atrophy, and benign Fasciculation syndrome. FDI muscles of ALS patients were classified by the presence or absence of neurogenic changes on needle electromyography. RESULTS Both sensory nerve electrical stimulation and vibration significantly increased the frequency of Fasciculations in neurogenic FDI muscles of ALS patients, but not in the remaining groups. DISCUSSION Our results favour increased excitability of LMNs when affected by the disease process in ALS. We found that some Fasciculations originating in these neurons in ALS are susceptible to modulation by sensory input. Muscle Nerve 59:688-693, 2019.
-
Fasciculation in amyotrophic lateral sclerosis: origin and pathophysiological relevance.
Journal of Neurology Neurosurgery and Psychiatry, 2017Co-Authors: Mamede De Carvalho, Matthew C. Kiernan, Michael SwashAbstract:This review considers the origin and significance of Fasciculations in neurological practice, with an emphasis on Fasciculations in amyotrophic lateral sclerosis (ALS), and in benign Fasciculation syndromes. Fasciculation represents a brief spontaneous contraction that affects a small number of muscle fibres, causing a flicker of movement under the skin. While an understanding of the role of Fasciculation in ALS remains incomplete, Fasciculations derive from ectopic activity generated in the motor system. A proximal origin seems likely to contribute to the generation of Fasciculation in the early stages of ALS, while distal sites of origin become more prominent later in the disease, associated with distal motor axonal sprouting as part of the reinnervation response that develops secondary to loss of motor neurons. Fasciculations are distinct from the recurrent trains of axonal firing described in neuromyotonia. Fasciculation without weakness, muscle atrophy or increased tendon reflexes suggests a benign Fasciculation syndrome, even when of sudden onset. Regardless of origin, Fasciculations often present as the initial abnormality in ALS, an early harbinger of dysfunction and aberrant firing of motor neurons.
-
Fasciculation discharge frequency in amyotrophic lateral sclerosis and related disorders
Clinical Neurophysiology, 2016Co-Authors: Mamede De Carvalho, Michael SwashAbstract:Abstract Objective In amyotrophic lateral sclerosis (ALS), Fasciculations are believed to become less frequent during disease progression, associated with the loss of motor units. To address this issue, we studied the variation of Fasciculation potential (FPs) frequency as evaluated by surface electromyography of the first dorsal interosseous muscle (1st DI) in patients with ALS and other related disorders, and to relate this change with the neurophysiological index (NI), a surrogate measure of functional motor units. Methods We measured the FP frequency and mean amplitude during a two minute recording of the relaxed right first dorsal interosseous muscle (1st DI) in 34 ALS patients, 9 subjects with benign Fasciculations (BFS), 6 with primary lateral sclerosis (PLS) and 4 with spinal muscle atrophy (SMA). ALS patients were evaluated 2–5times at 4month intervals, people with BFS were evaluated 3–4 times at the same interval, those with SMA and PLS were evaluated at 6month intervals 2–4times. The NI was derived from the amplitude of the motor response and F-wave frequency after distal ulnar nerve stimulation. Results The NI decreased significantly in ALS ( p Conclusion In ALS, the generators of FPs remain active even when the number of motor units is quite reduced, consistent with increased motoneuron excitability associated with unstable axonal sprouts during the process of continuous partial reinnervation. In BFS and other neuromuscular disorders, including SMA, the FP frequency is stable over time, suggesting mature motor axons that are not hyperexcitable and less prone to ectopic activity. Significance In ALS, the FP firing frequency does not decline significantly over several months, in spite of a marked reduction in the number of functional motor units.
-
Origin of Fasciculations in root lesions.
Clinical Neurophysiology, 2015Co-Authors: Mamede De Carvalho, Michael SwashAbstract:Abstract Objective Fasciculations are occasionally observed in root lesions, but their site of origin is uncertain. Methods We studied the origin of Fasciculations (FPs) in consecutive patients with mild chronic L5 root lesions, excluding peripheral nerve lesion. We used a novel technique of double-EMG needle recording, in which each needle was placed in the territory of separate motor units. With this technique the observation of synchronous FPs implies an origin proximal to distal axonal branching. Results FPs were found in 13% of 84 consecutive patients with mild chronic L5 root lesions. In 25% they were synchronous in different motor units. Conclusions We suggest that in mild L5 root lesions most FPs have an origin at distal branches but some FPs originate proximally (25%), possibly at the site of nerve compression. Significance The proximal site of compression and more distal sites may both initiate Fasciculation potentials in proximal root lesions.
-
modulation of Fasciculation frequency in amyotrophic lateral sclerosis
Journal of Neurology Neurosurgery and Psychiatry, 2015Co-Authors: Mamede De Carvalho, Michael Swash, Antónia Turkman, Susana PintoAbstract:Fasciculations are a major clinical feature, present very early in the natural history of amyotrophic lateral sclerosis (ALS).1 They represent spontaneous discharges of motor units or portions of motor units, that can sometimes also be activated volitionally.2 There is no objective evidence that Fasciculation potential (FP) discharges can be modulated by the patient or by the examiner. In this study we have addressed this issue in ALS, spinal muscular atrophy (SMA) and benign Fasciculation syndrome (BFS). We evaluated Fasciculation firing frequency, using surface electromyographic (EMG) recordings from the first dorsal interosseous (DI) muscle in the hand at rest, and randomly after a period of maximal contraction, thus involving upper and lower motor neuron excitation, after radial sensory nerve stimulation and after supramaximal electrical stimulation of the ulnar nerve at the wrist, representing lower motor neuron excitation. We studied 75 patients with definite or probable ALS, excluding patients with polyneuropathy, diabetes or ulnar neuropathy (median age 61 years (range 27–75 years), median disease duration 12 months (range 3–24 months), 48 were men). One hand, in which first DI strength was 4 on the MRC (Medical Research Council) score 4 or 5, was studied in each patient. In each participant, FPs were recorded at rest in the first DI muscle. Six patients with SMA type 3 were studied (median age 45 years; range 28–60 years). …
Kerry R. Mills - One of the best experts on this subject based on the ideXlab platform.
-
Fasciculations demonstrate daytime consistency in amyotrophic lateral sclerosis
Muscle & Nerve, 2020Co-Authors: James Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Urooba Masood, Emmanuel M. Drakakis, Martyn G. Boutelle, Christopher ShawAbstract:Introduction Fasciculations represent early neuronal hyperexcitability in amyotrophic lateral sclerosis (ALS). To aid calibration as a disease biomarker, we set out to characterize the daytime variability of Fasciculation firing. Methods Fasciculation awareness scores were compiled from 19 ALS patients. In addition, 10 ALS patients prospectively underwent high-density surface electromyographic (HDSEMG) recordings from biceps and gastrocnemius at three time-points during a single day. Results Daytime Fasciculation awareness scores were low (mean: 0.28 muscle groups), demonstrating significant variability (coefficient of variation: 303%). Biceps HDSEMG recordings were highly consistent for Fasciculation potential frequency (intraclass correlation coefficient [ICC] = 95%, n = 19) and the interquartile range of Fasciculation potential amplitude (ICC = 95%, n = 19). These parameters exhibited robustness to observed fluctuations in data quality parameters. Gastrocnemius demonstrated more modest levels of consistency overall (44% to 62%, n = 20). Discussion There was remarkable daytime consistency of Fasciculation firing in the biceps of ALS patients, despite sparse and intermittent awareness among patients' accounts.
-
The rise and fall of Fasciculations in amyotrophic lateral sclerosis.
Brain communications, 2020Co-Authors: James Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Emmanuel M. Drakakis, Martyn G. Boutelle, Christopher ShawAbstract:Amyotrophic lateral sclerosis is a devastating neurodegenerative disease with a median survival of 3 years from symptom onset. Accessible and reliable biomarkers of motor neuron decline are urgently needed to quicken the pace of drug discovery. Fasciculations represent an early pathophysiological hallmark of amyotrophic lateral sclerosis and can be reliably detected by high-density surface electromyography. We set out to quantify Fasciculation potentials prospectively over 14 months, seeking comparisons with established markers of disease progression. Twenty patients with amyotrophic lateral sclerosis and five patients with benign Fasciculation syndrome underwent up to seven assessments each. At each assessment, we performed the amyotrophic lateral sclerosis-functional rating scale, sum power score, slow vital capacity, 30-min high-density surface electromyography recordings from biceps and gastrocnemius and the motor unit number index. We employed the Surface Potential Quantification Engine, which is an automated analytical tool to detect and characterize Fasciculations. Linear mixed-effect models were employed to account for the pseudoreplication of serial measurements. The amyotrophic lateral sclerosis-functional rating scale declined by 0.65 points per month (P 900 000 Fasciculations revealed inter-Fasciculation intervals
-
preprocessing surface emg data removes voluntary muscle activity and enhances spiqe Fasciculation analysis
Clinical Neurophysiology, 2020Co-Authors: James Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Emmanuel M. Drakakis, Martyn G. Boutelle, C ShawAbstract:Abstract Objectives Fasciculations are a clinical hallmark of amyotrophic lateral sclerosis (ALS). The Surface Potential Quantification Engine (SPiQE) is a novel analytical tool to identify Fasciculation potentials from high-density surface electromyography (HDSEMG). This method was accurate on relaxed recordings amidst fluctuating noise levels. To avoid time-consuming manual exclusion of voluntary muscle activity, we developed a method capable of rapidly excluding voluntary potentials and integrating with the established SPiQE pipeline. Methods Six ALS patients, one patient with benign Fasciculation syndrome and one patient with multifocal motor neuropathy underwent monthly thirty-minute HDSEMG from biceps and gastrocnemius. In MATLAB, we developed and compared the performance of four Active Voluntary IDentification (AVID) strategies, producing a decision aid for optimal selection. Results Assessment of 601 one-minute recordings permitted the development of sensitive, specific and screening strategies to exclude voluntary potentials. Exclusion times (0.2–13.1 minutes), processing times (10.7–49.5 seconds) and Fasciculation frequencies (27.4–71.1 per minute) for 165 thirty-minute recordings were compared. The overall median Fasciculation frequency was 40.5 per minute (10.6–79.4 IQR). Conclusion We hereby introduce AVID as a flexible, targeted approach to exclude voluntary muscle activity from HDSEMG recordings. Significance Longitudinal quantification of Fasciculations in ALS could provide unique insight into motor neuron health.
-
spiqe an automated analytical tool for detecting and characterising Fasciculations in amyotrophic lateral sclerosis
Clinical Neurophysiology, 2019Co-Authors: J Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Emmanuel M. Drakakis, Martyn G. Boutelle, C ShawAbstract:Abstract Objectives Fasciculations are a clinical hallmark of amyotrophic lateral sclerosis (ALS). Compared to concentric needle EMG, high-density surface EMG (HDSEMG) is non-invasive and records Fasciculation potentials (FPs) from greater muscle volumes over longer durations. To detect and characterise FPs from vast data sets generated by serial HDSEMG, we developed an automated analytical tool. Methods Six ALS patients and two control patients (one with benign Fasciculation syndrome and one with multifocal motor neuropathy) underwent 30-minute HDSEMG from biceps and gastrocnemius monthly. In MATLAB we developed a novel, innovative method to identify FPs amidst fluctuating noise levels. One hundred repeats of 5-fold cross validation estimated the model’s predictive ability. Results By applying this method, we identified 5,318 FPs from 80 minutes of recordings with a sensitivity of 83.6% (+/− 0.2 SEM), specificity of 91.6% (+/− 0.1 SEM) and classification accuracy of 87.9% (+/− 0.1 SEM). An amplitude exclusion threshold (100 μV) removed excessively noisy data without compromising sensitivity. The resulting automated FP counts were not significantly different to the manual counts (p = 0.394). Conclusion We have devised and internally validated an automated method to accurately identify FPs from HDSEMG, a technique we have named Surface Potential Quantification Engine (SPiQE). Significance Longitudinal quantification of Fasciculations in ALS could provide unique insight into motor neuron health.
-
spiqe an automated analytical tool for detecting and characterising Fasciculations in amyotrophic lateral sclerosis
bioRxiv, 2019Co-Authors: J Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Emmanuel M. Drakakis, Martyn G. Boutelle, C ShawAbstract:Abstract OBJECTIVES Fasciculations are a clinical hallmark of amyotrophic lateral sclerosis (ALS). Compared to concentric needle EMG, high-density surface EMG (HDSEMG) is non-invasive and records Fasciculation potentials (FPs) from greater muscle volumes over longer durations. To detect and characterise FPs from vast data sets generated by serial HDSEMG, we developed an automated analytical tool. METHODS Six ALS patients and two control patients (one with benign Fasciculation syndrome and one with multifocal motor neuropathy) underwent 30-minute HDSEMG from biceps and gastrocnemius monthly. In MATLAB we developed a novel, innovative method to identify FPs amidst fluctuating noise levels. One hundred repeats of 5-fold cross validation estimated the model’s predictive ability. RESULTS By applying this method, we identified 5,318 FPs from 80 minutes of recordings with a sensitivity of 83.6% (+/-0.2 SEM), specificity of 91.6% (+/-0.1 SEM) and classification accuracy of 87.9% (+/-0.1 SEM). An amplitude exclusion threshold (100μV) removed excessively noisy data without compromising sensitivity. The resulting automated FP counts were not significantly different to the manual counts (p=0.394). CONCLUSION We have devised and internally validated an automated method to accurately identify FPs from HDSEMG, a technique we have named Surface Potential Quantification Engine (SPiQE). SIGNIFICANCE Longitudinal quantification of Fasciculations in ALS could provide unique insight into motor neuron health. Highlights SPiQE combines serial high-density surface EMG with an innovative signal-processing methodology SPiQE identifies Fasciculations in ALS patients with high sensitivity and specificity The optimal noise-responsive model achieves an average classification accuracy of 88%
C Shaw - One of the best experts on this subject based on the ideXlab platform.
-
preprocessing surface emg data removes voluntary muscle activity and enhances spiqe Fasciculation analysis
Clinical Neurophysiology, 2020Co-Authors: James Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Emmanuel M. Drakakis, Martyn G. Boutelle, C ShawAbstract:Abstract Objectives Fasciculations are a clinical hallmark of amyotrophic lateral sclerosis (ALS). The Surface Potential Quantification Engine (SPiQE) is a novel analytical tool to identify Fasciculation potentials from high-density surface electromyography (HDSEMG). This method was accurate on relaxed recordings amidst fluctuating noise levels. To avoid time-consuming manual exclusion of voluntary muscle activity, we developed a method capable of rapidly excluding voluntary potentials and integrating with the established SPiQE pipeline. Methods Six ALS patients, one patient with benign Fasciculation syndrome and one patient with multifocal motor neuropathy underwent monthly thirty-minute HDSEMG from biceps and gastrocnemius. In MATLAB, we developed and compared the performance of four Active Voluntary IDentification (AVID) strategies, producing a decision aid for optimal selection. Results Assessment of 601 one-minute recordings permitted the development of sensitive, specific and screening strategies to exclude voluntary potentials. Exclusion times (0.2–13.1 minutes), processing times (10.7–49.5 seconds) and Fasciculation frequencies (27.4–71.1 per minute) for 165 thirty-minute recordings were compared. The overall median Fasciculation frequency was 40.5 per minute (10.6–79.4 IQR). Conclusion We hereby introduce AVID as a flexible, targeted approach to exclude voluntary muscle activity from HDSEMG recordings. Significance Longitudinal quantification of Fasciculations in ALS could provide unique insight into motor neuron health.
-
spiqe an automated analytical tool for detecting and characterising Fasciculations in amyotrophic lateral sclerosis
Clinical Neurophysiology, 2019Co-Authors: J Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Emmanuel M. Drakakis, Martyn G. Boutelle, C ShawAbstract:Abstract Objectives Fasciculations are a clinical hallmark of amyotrophic lateral sclerosis (ALS). Compared to concentric needle EMG, high-density surface EMG (HDSEMG) is non-invasive and records Fasciculation potentials (FPs) from greater muscle volumes over longer durations. To detect and characterise FPs from vast data sets generated by serial HDSEMG, we developed an automated analytical tool. Methods Six ALS patients and two control patients (one with benign Fasciculation syndrome and one with multifocal motor neuropathy) underwent 30-minute HDSEMG from biceps and gastrocnemius monthly. In MATLAB we developed a novel, innovative method to identify FPs amidst fluctuating noise levels. One hundred repeats of 5-fold cross validation estimated the model’s predictive ability. Results By applying this method, we identified 5,318 FPs from 80 minutes of recordings with a sensitivity of 83.6% (+/− 0.2 SEM), specificity of 91.6% (+/− 0.1 SEM) and classification accuracy of 87.9% (+/− 0.1 SEM). An amplitude exclusion threshold (100 μV) removed excessively noisy data without compromising sensitivity. The resulting automated FP counts were not significantly different to the manual counts (p = 0.394). Conclusion We have devised and internally validated an automated method to accurately identify FPs from HDSEMG, a technique we have named Surface Potential Quantification Engine (SPiQE). Significance Longitudinal quantification of Fasciculations in ALS could provide unique insight into motor neuron health.
-
spiqe an automated analytical tool for detecting and characterising Fasciculations in amyotrophic lateral sclerosis
bioRxiv, 2019Co-Authors: J Bashford, Kerry R. Mills, Aidan Wickham, Raquel Iniesta, Emmanuel M. Drakakis, Martyn G. Boutelle, C ShawAbstract:Abstract OBJECTIVES Fasciculations are a clinical hallmark of amyotrophic lateral sclerosis (ALS). Compared to concentric needle EMG, high-density surface EMG (HDSEMG) is non-invasive and records Fasciculation potentials (FPs) from greater muscle volumes over longer durations. To detect and characterise FPs from vast data sets generated by serial HDSEMG, we developed an automated analytical tool. METHODS Six ALS patients and two control patients (one with benign Fasciculation syndrome and one with multifocal motor neuropathy) underwent 30-minute HDSEMG from biceps and gastrocnemius monthly. In MATLAB we developed a novel, innovative method to identify FPs amidst fluctuating noise levels. One hundred repeats of 5-fold cross validation estimated the model’s predictive ability. RESULTS By applying this method, we identified 5,318 FPs from 80 minutes of recordings with a sensitivity of 83.6% (+/-0.2 SEM), specificity of 91.6% (+/-0.1 SEM) and classification accuracy of 87.9% (+/-0.1 SEM). An amplitude exclusion threshold (100μV) removed excessively noisy data without compromising sensitivity. The resulting automated FP counts were not significantly different to the manual counts (p=0.394). CONCLUSION We have devised and internally validated an automated method to accurately identify FPs from HDSEMG, a technique we have named Surface Potential Quantification Engine (SPiQE). SIGNIFICANCE Longitudinal quantification of Fasciculations in ALS could provide unique insight into motor neuron health. Highlights SPiQE combines serial high-density surface EMG with an innovative signal-processing methodology SPiQE identifies Fasciculations in ALS patients with high sensitivity and specificity The optimal noise-responsive model achieves an average classification accuracy of 88%
Marc Tessierlavigne - One of the best experts on this subject based on the ideXlab platform.
-
autocrine juxtaparacrine regulation of axon Fasciculation by slit robo signaling
Nature Neuroscience, 2012Co-Authors: Alexander Jaworski, Marc TessierlavigneAbstract:Axons travel to their targets in bundles or fascicles, but the molecules regulating Fasciculation remain incompletely characterized. We found that Slit2 and its Robo receptors are expressed by motor axons, and that inactivation of Slit2 or Robo1 and Robo2 in mice caused axons to defasciculate prematurely at muscle targets. In vitro, Slit2 secreted by motoneurons regulated Fasciculation through Robo1 and Robo2. These results support the idea that Slit2 promotes axon Fasciculation via an autocrine and/or juxtaparacrine mechanism.
