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This work introduces a real-time intention decoding algorithm grounded in muscle synergies (Syn-ID). The algorithm detects the electromyographic (EMG) onset and infers the direction of the movement during reaching tasks to control a powered shoulder–elbow exoskeleton. Features related to muscle synergies are used in a Gaussian Mixture Model and probability accumulation-based logic to infer the user’s movement direction. The performance of the algorithm was verified by a feasibility study including eight healthy participants. The experiments comprised a transparent session, during which the exoskeleton did not provide any assistance, and an assistive session in which the Syn-ID strategy was employed. Participants were asked to reach eight targets equally spaced on a circumference of 25 cm radius (adjusted chance level: 18.1%). The results showed an average accuracy of 48.7% after 0.6 s from the EMG onset. Most of the confusion of the estimate was found along directions adjacent to the actual one (type 1 error: 33.4%). Effects of the assistance were observed in a statistically significant reduction in the activation of Posterior Deltoid and Triceps Brachii. The final positions of the movements during the assistive session were on average 1.42 cm far from the expected ones, both when the directions were estimated correctly and when type 1 errors occurred. Therefore, combining accurate estimates with type 1 errors, we computed a modified accuracy of 82.10±6.34%. Results were benchmarked with respect to a purely kinematics-based approach. The Syn-ID showed better performance in the first portion of the movement (0.14 s after EMG onset).
We aim to understand the effects of hydration changes on athletes’ neuromuscular performance, on body water compartments, fat-free mass hydration and hydration biomarkers and to test the effects of the intervention on the response of acute dehydration in the hydration indexes. The H2OAthletes study (clinicaltrials.gov ID: NCT05380089) is a randomised controlled trial in thirty-eight national/international athletes of both sexes with low total water intake (WI) (i.e. < 35·0 ml/kg/d). In the intervention, participants will be randomly assigned to the control (CG, n 19) or experimental group (EG, n 19). During the 4-day intervention, WI will be maintained in the CG and increased in the EG (i.e. > 45·0 ml/kg/d). Exercise-induced dehydration protocols with thermal stress will be performed before and after the intervention. Neuromuscular performance (knee extension/flexion with electromyography and handgrip), hydration indexes (serum, urine and saliva osmolality), body water compartments and water flux (dilution techniques, body composition (four-compartment model) and biochemical parameters (vasopressin and Na) will be evaluated. This trial will provide novel evidence about the effects of hydration changes on neuromuscular function and hydration status in athletes with low WI, providing useful information for athletes and sports-related professionals aiming to improve athletic performance.
To evaluate the outcomes of reinnervation techniques for the treatment of adult unilateral vocal fold paralysis and bilateral vocal fold paralysis.
Methods
A literature review was conducted in the Embase and Medline databases in English, with no limitations on the publication date. The outcome parameters of interest included visual, subjective perceptual, acoustic, aerodynamic analysis and electromyography. A meta-analysis with a random-effects model and inverse variance was calculated.
Results
The systematic Preferred Reporting Items for Systematic Reviews and Meta-Analyses approach resulted in 27 studies, totalling 803 patients (747 unilateral cases and 56 bilateral cases). Thyroid cancer and/or surgery had caused unilateral vocal fold paralysis in 74.8 per cent of cases and bilateral vocal fold paralysis in 69.6 per cent of cases. Statistically significant improvements in patients were observed for voice, deglutition and decannulation (bilateral vocal fold paralysis). Meta-analysis of 10 reinnervation techniques was calculated for the maximum phonation time of 184 patients.
Conclusion
Reinnervation was shown to improve voice, swallowing and decannulation, but studies lacked control groups, limiting generalisability. Larger studies with controls are needed.
Nerve conduction velocity in degenerative disease depends on which nerve fibres are affected. If the largest diameter ones are spared, velocity will be normal. Otherwise, there will be a decrease of up to 30 per cent. The localising value of nerve conduction studies in degenerative disease is limited though hardly required after focal trauma. Electromyography will usually also be needed. An abnormal finding will always be found if either the stimulating or recording electrode lies over a region of degeneration. Preganglionic pathology occurring in radiculopathies is associated with normal sensory conduction. The degree to which sensory nerve action potentials (SNAPs) are reduced in amplitude is a useful guide to the severity of the pathology within postganglionic fibres. These concepts are illustrated with simple but helpful diagrams.
Diagnostic methods share the same common objectives: what is the location of the disorder? What is the pathology? What is the severity and prognosis? Can the abnormality be monitored? The way in which these questions are related to muscle, the neuromuscular junction and the peripheral nervous system are described. The techniques used in these diagnoses are electromyography and nerve conduction studies. The structures and the application of the techniques to them are shown diagrammatically.
Returning to the diagnostic questions posed in Chapter 1 (Introduction), the methods by which electromyography and nerve conduction studies identify and localise pathology within muscle, nerve and the neuromuscular junction are reviewed. Similarly, the methods of assessing severity are recalled. The facility to monitor conditions is limited. The book ends with the outline Summary Table, presented at the beginning of the book, completed, as promised.
The principles of electromyography, including single-fibre electromyography and nerve conduction studies, are described simply, supported by clear diagrams and screenshots of high quality recordings. After a brief overview of anatomy, physiology, pathology and technical matters including electrodes, amplifiers and volume conduction, the way these principles aid the diagnosis of disorders of nerves, muscles and neuromuscular junctions is explained. The book concludes with the findings in common clinical conditions and explores the concept of normal vs abnormal values. This is an invaluable introductory text for trainees in clinical neurophysiology. Clinicians in specialties such as neurology, orthopaedic surgery, rheumatology, general medicine, physical medicine and rehabilitation will benefit from guidance on selecting patients for referral and assistance with the interpretation of the results. Based on the expertise of an author who has spent 25 years practising and teaching the subject, readers can be assured of a wealth of knowledge within these pages.
Negative symptoms such as blunted facial expressivity are characteristic of schizophrenia. However, it is not well-understood if and what abnormalities are present in individuals at clinical high-risk (CHR) for psychosis.
Methods
This experimental study employed facial electromyography (left zygomaticus major and left corrugator supercilia) in a sample of CHR individuals (N = 34) and healthy controls (N = 32) to detect alterations in facial expressions in response to emotionally evocative film clips and to determine links with symptoms.
Results
Findings revealed that the CHR group showed facial blunting manifested in reduced zygomatic activity in response to an excitement (but not amusement, fear, or sadness) film clip compared to controls. Reductions in zygomatic activity in the CHR group emerged in response to the emotionally evocative peak period of the excitement film clip. Lower zygomaticus activity during the excitement clip was related to anxiety while lower rates of change in zygomatic activity during the excitement video clip were related to higher psychosis risk conversion scores.
Conclusions
Together, these findings inform vulnerability/disease driving mechanisms and biomarker and treatment development.
Long latency reflexes (LLRs) are impaired in a wide array of clinical conditions. We aimed to illustrate the clinical applications and recent advances of LLR in various neurological disorders from a systematic review of published literature.
Methods:
We reviewed the literature using appropriately chosen MeSH terms on the database platforms of MEDLINE, Web of Sciences, and Google Scholar for all the articles from 1st January 1975 to 2nd February 2021 using the search terms “long loop reflex”, “long latency reflex” and “C-reflex”. The included articles were analyzed and reported using synthesis without meta-analysis (SWiM) guidelines.
Results:
Based on our selection criteria, 40 articles were selected for the systematic review. The various diseases included parkinsonian syndromes (11 studies, 217 patients), Huntington’s disease (10 studies, 209 patients), myoclonus of varied etiologies (13 studies, 127 patients) including progressive myoclonic epilepsy (5 studies, 63 patients) and multiple sclerosis (6 studies, 200 patients). Patients with parkinsonian syndromes showed large amplitude LLR II response. Enlarged LLR II was also found in myoclonus of various etiologies. LLR II response was delayed or absent in Huntington’s disease. Delayed LLR II response was present in multiple sclerosis. Among the other diseases, LLR response varied according to the location of cerebellar lesions while the results were equivocal in patients with essential tremor.
Conclusions:
Abnormal LLR is observed in many neurological disorders. However, larger systematic studies are required in many neurological disorders in order to establish its role in diagnosis and management.
Clinical observations and subjective judgements have traditionally been used to evaluate patients with muscular and neurological disorders. As a result, identifying and analyzing functional improvements are difficult, especially in the absence of expertise. Quantitative assessment, which serves as the motivation for this study, is an essential prerequisite to forecast the task of the rehabilitation device in order to develop rehabilitation training. This work provides a quantitative assessment tool for muscle weakness in the human upper limbs for robotic-assisted rehabilitation. The goal is to map the assessment metrics to the recommended rehabilitation exercises. Measurable interaction forces and muscle correlation factors are the selected parameters to design a framework for muscular nerve cell condition detection and appropriate limb trajectory selection. In this work, a data collection setup is intended for extracting muscle intervention and assessment using MyoMeter, Goniometer and surface electromyography data for upper limbs. Force signals and human physiological response data are evaluated and categorized to infer the relevant progress. Based upon the most influencing muscles, curve fitting is performed. Trajectory-based data points are collected through a scaled geometric Open-Sim musculoskeletal model that fits the subject’s anthropometric data. These data are found to be most suitable to prescribe relevant exercise and to design customized robotic assistance. Case studies demonstrate the approach’s efficacy, including optimally synthesized automated configuration for the desired trajectory.
Electrodiagnostic testing, including nerve conduction studies (NCS) and electromyography (EMG), assists with localizing lesions within the peripheral nervous system. NCS/EMG in children can be technically challenging and its relevance has been questioned in the era of affordable genetic testing. NCS/EMG provides information that may not be available in the examination of a young or developmentally delayed child. Our goal was to review the volume and referral sources of NCS/EMG studies and evaluate its feasibility and diagnostic yield at a pediatric tertiary care hospital.
Methods:
Retrospective chart review of NCS/EMG studies done in pediatric patients at one center from 2014 to 2019.
Results:
A total of 725 studies were performed, with a median age of 13.2 years (range 0–18 years). The annual number of studies remained constant throughout the study period. Neurologists and surgeons were the most common referral sources, but an increased number of referrals from geneticists was observed. Most (94.5%) NCS/EMG were done on awake patients, with only 5.5% of studies being terminated early due to tolerability of the patient. Of all studies, 326/725 (44%) demonstrated a neuromuscular abnormality, of which 63.5% (207/326) were acquired conditions. Mononeuropathies and polyneuropathies were the most common electrophysiologic diagnoses.
Discussion:
Our study indicates that NCS/EMG remains a useful diagnostic tool, both for the diagnosis of acquired neuromuscular conditions but also as an adjunct for interpreting genetic results, as indicated by the recent increase in referrals from geneticists. Overall NCS/EMG is well tolerated and able to be performed without sedation in children of all ages.
We have developed a one-of-a-kind hand exoskeleton, called Maestro, which can power finger movements of those surviving severe disabilities to complete daily tasks using compliant joints. In this paper, we present results from an electromyography (EMG) control strategy conducted with spinal cord injury (SCI) patients (C5, C6, and C7) in which the subjects completed daily tasks controlling Maestro with EMG signals from their forearm muscles. With its compliant actuation and its degrees of freedom that match the natural finger movements, Maestro is capable of helping the subjects grasp and manipulate a variety of daily objects (more than 15 from a standardized set). To generate control commands for Maestro, an artificial neural network algorithm was implemented along with a probabilistic control approach to classify and deliver four hand poses robustly with three EMG signals measured from the forearm and palm. Increase in the scores of a standardized test, called the Sollerman hand function test, and enhancement in different aspects of grasping such as strength shows feasibility that Maestro can be capable of improving the hand function of SCI subjects.
The pathogenesis of otitis media is related to Eustachian tube dysfunction. The tensor veli palatini muscle actively opens the Eustachian tube and promotes middle-ear ventilation. This study describes a technique for paratubal electromyography that uses a surface, non-invasive electrode able to record tensor veli palatini muscle activity during swallowing.
Methods:
Twenty otitis media patients and 10 healthy patients underwent tensor veli palatini electromyography. Activity of this muscle before and after Eustachian tube rehabilitation was also assessed.
Results:
In 78.5 per cent of patients, the electromyography duration phase and/or amplitude were reduced in the affected side. The muscle action potential was impaired in all patients who underwent Eustachian tube rehabilitation.
Conclusion:
This study confirmed that Eustachian tube muscle dysfunction has a role in otitis media pathogenesis and showed that muscle activity increases after Eustachian tube rehabilitation therapy.
Objectives: 1) Assess which electrodiagnostic studies Canadian clinicians use to aid in the diagnosis of carpal tunnel syndrome (CTS). 2) Assess whether Canadian clinicians follow the American Association of Neuromuscular & Electrodiagnostic Medicine/American Academy of Neurology/American Academy of Physical Medicine and Rehabilitation Practice Parameter for Electrodiagnostic Studies in CTS. 3) Assess how Canadian clinicians manage CTS once a diagnosis has been established. Methods: In this prospective observational study, an electronic survey was sent to all members of the Canadian Neuromuscular Group (CNMG) and the Canadian Association of Physical Medicine and Rehabilitation (CAPM&R) Neuromuscular Special Interest Group. Questions addressed which electrodiagnostic tests were being routinely used for the diagnosis of carpal tunnel syndrome. Management recommendations for CTS was also explored. Results: Of the 70 individuals who completed the survey, fourteen different nerve conduction study techniques were reported. Overall, 36/70 (51%) of participants followed the AANEM/AAN/AAPM&R Practice Parameter. The standard followed by the fewest of our respondents with 64% compliance (45/70) was the use of a standard distance of 13 to 14 cm with respect to the median sensory nerve conduction study. Regarding management, 99% would recommend splinting in the case of mild CTS. In moderate CTS, splinting was recommended by 91% of clinicians and 68% would also consider referral for surgery. In severe CTS, most recommended surgery (93%). Conclusions: There is considerable variability in terms of which electrodiagnostic tests Canadian clinicians perform for CTS. Canadian clinicians are encouraged to adhere to the AANEM/AAN/AAPM&R Practice Parameter for Electrodiagnostic Studies in CTS.
To study stimulation-related facial electromyographic (FEMG) activity in intensive care unit (ICU) patients, develop an algorithm for quantifying the FEMG activity, and to optimize the algorithm for monitoring the sedation state of ICU patients.
Methods
First, the characteristics of FEMG response patterns related to vocal stimulation of 17 ICU patients were studied. Second, we collected continuous FEMG data from 30 ICU patients. Based on these data, we developed the Responsiveness Index (RI) algorithm that quantifies FEMG responses. Third, we compared the RI values with clinical sedation level assessments and adjusted algorithm parameters for best performance.
Results
In patients who produced a clinically observed response to the vocal stimulus, the poststimulus FEMG power was 0.33 µV higher than the prestimulus power. In nonresponding patients, there was no difference. The sensitivity and specificity of the developed RI for detecting deep sedation in the subgroup with low probability of encephalopathy were 0.90 and 0.79, respectively.
Conclusion
Consistent FEMG patterns were found related to standard stimulation of ICU patients. A simple and robust algorithm was developed and good correlation with clinical sedation scores achieved in the development data.
Over the past 150 years, regional post-traumatic pain has had various appellations, most recently complex regional pain syndrome (CRPS) and post-traumatic neuralgia (PTN). CPRS appears to be a complex endophenotype of PTN that involves neurogenic inflammation as well as pain. There is increasing evidence that peripheral and central inflammatory cascades triggered by nerve injuries contribute to CRPS and perhaps PTN as well. PTN and CRPS often spread beyond classic individual nerve territories, although when patients are asked to outline the epicenter, or most abnormal area, this frequently identifies a specific nerve injury. The most dramatic CRPS and PTN-associated movement abnormality is fixed distal dystonia. Nerve conduction studies and electromyography are useful in documenting and localizing peripheral nerve damage. Currently, four classes of medications are primary options for chronic CRPS/PTN: tricyclics and serotonin-noradrenaline reuptake inhibitors; opioids; gabapentinoids; and topical or systemic local anesthetics.
The recurrent laryngeal nerve can be injured during surgery. This study investigated recurrent laryngeal nerve reinnervation.
Objective:
To study the short-term effects of primary anastomosis of the recurrent laryngeal nerve, by laryngeal electromyography and histopathological analysis, in a rabbit model.
Method:
Twenty Zealand rabbits underwent either right recurrent laryngeal nerve (1) transection with excision of 1 cm or (2) transection and end-to-end primary anastomosis. Vocal fold movements, laryngeal electromyography results and histological changes were recorded.
Results:
Vocal fold analysis showed a paramedian vocal fold in both groups, with perceptible vibratory movements in group two. Electromyography revealed total denervation potentials in group one, but denervation and regeneration signs in group two. Histopathologically, hyperkeratosis and parakeratosis of the vocal fold mucosa were seen in group one, and signs of parakeratosis and hyperplasia in group two.
Conclusion:
Even under ideal conditions for primary recurrent laryngeal nerve anastomosis, a return to normal muscle function is unlikely. However, such anastomosis prevents muscle atrophy, and should be performed as soon as possible. The degree of nerve recovery is associated with the number, amplitude and myelination level of fibrils returning to the original motor end-plaque.
The welfare consequences of long-distance transportation of animals remain a controversial topic. Animals that stand for most of the long journey (especially if additional muscular activity is required to deal with postural instability) are at risk of developing fatigue. Previous observational studies of behaviour and physiology suggested either that sheep do not become markedly fatigued by long journeys or that previous methods did not adequately identify fatigue. A range of behavioural and physiological measures were made on eight pairs of sheep during and after treadmill exercise. Within each pair of sheep, a treatment sheep was walked on a treadmill at 0.5 m/s for up to 5 h or until the sheep voluntarily stopped exercising or showed other signs of reduced performance, and a control sheep was exercised for two 10-min periods on either side of the exercise period for the treatment sheep. With the exception of one sheep that only walked for 4.5 h, all treatment sheep walked for 5 h without apparent difficulty. After exercise, the plasma cortisol concentration of treatment sheep was significantly greater than that of control sheep. However, there were no significant treatment effects on plasma creatine kinase activity or blood lactate concentration. After 5 h of exercise, there was a proportionate decrease in the median frequency of the electromyogram recorded over the m. semitendinosus, and this was significantly different from control sheep. There was no evidence that treatment sheep lay down sooner or for longer after treadmill exercise than controls. In sheep tested in a maze to examine whether there was increased motivation to rest after exercise, there was no significant difference between the times taken by treatment and control sheep to obtain a food reward. Qualitative behavioural assessment of the sheep by a panel of observers identified two main dimensions of sheep demeanour, but among descriptors elicited from observers only one person used a term associated with fatigue. No significant difference was found between the scores of treatment and control sheep on these two demeanour dimensions. Thus, there was little evidence that prolonged gentle walking exercise fatigues sheep. Further development of methods to both repeatedly induce and to identify fatigue in sheep is required.