Repetitive nerve stimulation and single‐fiber electromyography in the evaluation of patients with suspected myasthenia gravis or Lambert–Eaton myasthenic syndrome: Review of recent literature

Chiou‐Tan, Faye Y.; Gilchrist, James M.

doi:10.1002/mus.24745

Cited by 54 publications

(31 citation statements)

References 71 publications

(83 reference statements)

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“…Pathological conditions such as dystrophy (Lacourpaille et al, 2017 ) or spasticity (Granata et al, 2000 ) influence the EMD. Therefore, it is critical to detect changes in EMD due to muscle diseases such as myasthenia gravis or Lambert-Eaton myasthenic syndrome where the electromechanical coupling is disrupted (Chiou-Tan and Gilchrist, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

Intramuscular Pressure of Tibialis Anterior Reflects Ankle Torque but Does Not Follow Joint Angle-Torque Relationship

et al. 2018

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Intramuscular pressure (IMP) is the hydrostatic fluid pressure that is directly related to muscle force production. Electromechanical delay (EMD) provides a link between mechanical and electrophysiological quantities and IMP has potential to detect local electromechanical changes. The goal of this study was to assess the relationship of IMP with the mechanical and electrical characteristics of the tibialis anterior muscle (TA) activity at different ankle positions. We hypothesized that (1) the TA IMP and the surface EMG (sEMG) and fine-wire EMG (fwEMG) correlate to ankle joint torque, (2) the isometric force of TA increases at increased muscle lengths, which were imposed by a change in ankle angle and IMP follows the length-tension relationship characteristics, and (3) the electromechanical delay (EMD) is greater than the EMD of IMP during isometric contractions. Fourteen healthy adults [7 female; mean (SD) age = 26.9 (4.2) years old with 25.9 (5.5) kg/m2 body mass index] performed (i) three isometric dorsiflexion (DF) maximum voluntary contraction (MVC) and (ii) three isometric DF ramp contractions from 0 to 80% MVC at rate of 15% MVC/second at DF, Neutral, and plantarflexion (PF) positions. Ankle torque, IMP, TA fwEMG, and TA sEMG were measured simultaneously. The IMP, fwEMG, and sEMG were significantly correlated to the ankle torque during ramp contractions at each ankle position tested. This suggests that IMP captures in vivo mechanical properties of active muscles. The ankle torque changed significantly at different ankle positions however, the IMP did not reflect the change. This is explained with the opposing effects of higher compartmental pressure at DF in contrast to the increased force at PF position. Additionally, the onset of IMP activity is found to be significantly earlier than the onset of force which indicates that IMP can be designed to detect muscular changes in the course of neuromuscular diseases impairing electromechanical transmission.

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Section: Introductionmentioning

confidence: 99%

Intramuscular Pressure of Tibialis Anterior Reflects Ankle Torque but Does Not Follow Joint Angle-Torque Relationship

et al. 2018

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“…This was unexpected because earlier reports demonstrated increases in CMAP amplitude after DAP administration . Several factors may have played a role in these inconsistent results, among them the small number of participants, particularly at the end of withdrawal, due to rescue, and differences in the CMAP technique used at the different study sites . Indeed, CMAPs from only 10 of 12 (83%) of participants who continued DAP met the predetermined criteria for acceptability (see Table S3 online) on the first day of withdrawal (study day 3) and the number of acceptable CMAP studies was lower at each subsequent assessment.…”

Section: Discussionmentioning

confidence: 99%

“…10,11,14,25 Several factors may have played a role in these inconsistent results, among them the small number of participants, particularly at the end of withdrawal, due to rescue, and differences in the CMAP technique used at the different study sites. [26][27][28] Indeed, CMAPs from only 10 of 12 (83%) of participants who continued DAP met the predetermined criteria for acceptability (see Table S3 online) on the first day of withdrawal (study day 3) and the number of acceptable CMAP studies was lower at each subsequent assessment. This pattern was also observed in the group withdrawn from DAP: only 14 of 18 (78%) participants had acceptable CMAP studies on study day 3, and the number of acceptable CMAP studies declined at each subsequent assessment.…”

Section: Discussionmentioning

confidence: 99%

Validation of the triple timed up‐and‐go test in Lambert‐Eaton myasthenia

et al. 2019

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Introduction There are no validated, practical, and quantitative measures of disease severity in Lambert‐Eaton myasthenia (LEM). Methods Data from the Effectiveness of 3,4‐Diaminopyridine in Lambert‐Eaton Myasthenic Syndrome (DAPPER) trial were analyzed to assess triple timed up‐and‐go (3TUG) reproducibility and relationships between 3TUG times and other measures of LEM severity. Results The coverage probability technique showed ≥0.90 probability for an acceptable 3TUG difference of ≤0.2, indicating that it is reproducible in LEM patients. The correlation between 3TUG times and lower extremity function scores was significant in subjects who continued and in those who were withdrawn from 3,4‐diaminopyridine free base. Worsening patient‐reported Weakness Self‐Assessment Scale and Investigator Assessment of Treatment Effect scores corresponded with prolongation of 3TUG times. Discussion The 3TUG is reproducible, demonstrates construct validity for assessment of lower extremity function in LEM patients, and correlates with changes in patient and physician assessments. These findings, along with prior reliability studies, indicate 3TUG is a valid measure of disease severity in LEM.

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“…Our previous studies demonstrated that long grafts resulted in poor axonal regeneration and functional recovery compared with short grafts concurrent with an accumulation of cellular senescence. 3 As tissue subjected to prolonged ischemia develops numerous pathological processes, including cell damage, [4][5][6][7][8][9][10][11] an explanation for the poor regenerative outcomes and/or accumulation of senescence could be due to poor vascularization leading to ischemia and pathological consequences in long nerve grafts and constructs.…”

Section: Discussionmentioning

confidence: 99%

The effect of different low-frequency filters on concentric needle jitter in stimulated orbicularis oculi

2016

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Repetitive nerve stimulation and single‐fiber electromyography in the evaluation of patients with suspected myasthenia gravis or Lambert–Eaton myasthenic syndrome: Review of recent literature

Abstract: Electrodiagnostic testing continues to be useful for diagnosis of MG and LEMS, although the quality of the evidence is not great. This literature review summarizes RNS and jitter measurement of facial and respiratory muscles and use of concentric needle EMG for SFEMG.

Cited by 54 publications

References 71 publications

Intramuscular Pressure of Tibialis Anterior Reflects Ankle Torque but Does Not Follow Joint Angle-Torque Relationship

Intramuscular Pressure of Tibialis Anterior Reflects Ankle Torque but Does Not Follow Joint Angle-Torque Relationship

Validation of the triple timed up‐and‐go test in Lambert‐Eaton myasthenia

The effect of different low-frequency filters on concentric needle jitter in stimulated orbicularis oculi

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