The effects of bipolar electrode montage on conduction velocity estimation from the surface electromyogram

Beck, Rebecca; O’Malley, Mark; Dijk, Hans van; Nolan, P.; Stegeman, D.F.

doi:10.1016/j.jelekin.2003.09.024

Cited by 12 publications

(3 citation statements)

References 37 publications

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“…Pre-aligned EMG signals of 32 ms from electrode pairs with an inter-electrode distance of 12 mm (containing roughly one peak) were used to estimate the time delay between signals. The rationale behind selecting the double differential montage and inter-electrode distance of 12 mm was that these settings were empirically found to provide robust results (Beck et al 2004). Pre-aligning the signals was performed by an initial guess of MFCV equal to 4.1 m s −1 .…”

Section: Methodsmentioning

confidence: 99%

Unchanged muscle fiber conduction velocity relates to mild acidosis during exhaustive bicycling

et al. 2011

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Muscle fiber conduction velocity (MFCV) has often been shown to decrease during standardized fatiguing isometric contractions. However, several studies have indicated that the MFCV may remain constant during fatiguing dynamic exercise. It was investigated if these observations can be related to the absence of a large decrease in pH and if MFCV can be considered as a good indicator of acidosis, also during dynamic bicycle exercise. High-density surface electromyography (HDsEMG) was combined with read-outs of muscle energetics recorded by in vivo 31P magnetic resonance spectroscopy (MRS). Measurements were performed during serial exhausting bouts of bicycle exercise at three different workloads. The HDsEMG recordings revealed a small and incoherent variation of MFCV during all high-intensity exercise bouts. 31P MRS spectra revealed a moderate decrease in pH at the end of exercise (~0.3 units down to 6.8) and a rapid ancillary drop to pH 6.5 during recovery 30 s post-exercise. This additional degree of acidification caused a significant decrease in MFCV during cycling immediately after the rest period. From the data a significant correlation between MFCV and [H+] ([H+] = 10−pH) was calculated (p < 0.001, Pearson’s R = −0.87). Our results confirmed the previous observations of MFCV remaining constant during fatiguing dynamic exercise. A constant MFCV is in line with a low degree of acidification, considering the presence of a correlation between pH and MFCV after further increasing acidification.

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Section: Methodsmentioning

confidence: 99%

Unchanged muscle fiber conduction velocity relates to mild acidosis during exhaustive bicycling

et al. 2011

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“…Although consensus exists regarding the effect of IED on the EMG amplitude [4], [14], [15], [18], [31], precise figures for optimal and generally valid IEDs in single, bipolar recordings do not. IEDs ≤ 5 mm have been recommended for the specific case of studying action potential propagation using surface EMGs [32]. Indeed, this rather short IED threshold was not postulated to increase the representation of the target muscle excitation-that is, to increase sensitivity--or to suppress the representation of sources other than the target muscle-that is, to increase specificity--in the surface EMG.…”

Section: A Technical Considerations That Motivate Our Study and Justi...mentioning

confidence: 99%

The Sensitivity of Bipolar Electromyograms to Muscle Excitation Scales With the Inter-Electrode Distance

Vieira,

Cerone,

Botter

et al. 2023

IEEE Trans. Neural Syst. Rehabil. Eng.

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The value of surface electromyograms (EMGs) lies in their potential to non-invasively probe the neuromuscular system. Whether muscle excitation may be accurately inferred from bipolar EMGs depends on how much the detected signal is both sensitive and specific to the excitation of the target muscle. While both are known to be a function of inter-electrode distance (IED), specificity has been of long concern in the physiological literature. In contrast, sensitivity, at best, has been implicitly assumed. Here we provide evidence that IED imposes a biophysical constraint on the sensitivity of surface EMG. From 20 healthy subjects, we tested the hypothesis that excessively reducing IED provides EMGs with limited physiological content. We detected bipolar EMGs with IEDs varying from 5 mm to 50 mm from two skeletal muscles with distinct architectures, gastrocnemius and biceps brachii. Nonparametric statistics and Bayesian hierarchical modelling were used to evaluate the dependence of the onset of muscle excitation and signal-to-noise ratio (SNR) on the IED. Experimental results revealed that IED critically affects the sensitivity of bipolar EMGs for both muscles-indeliberately reducing IED provides EMGs that are not representative of the whole muscle, hampering validity. Simulation results substantiate the generalization of experimental results to small and large electrodes. Based on current and previous findings, we discuss a potentially valid procedure for defining the most appropriate IED for a single bipolar, surface recording-i.e., the distance from the electrode to the target muscle boundary may heuristically serve as a lower bound when choosing an IED.

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“…Os fatores técnicos que influenciam os registros de EMG são a colocação de eletrodos, a posição e a distância inter eletrodos (Macaluso & De Laat, 1995;Rilo et al, 1997;Hogrel, Duchene & Marini, 1998), o crosstalk ou registro indesejado de atividades oriundas de músculos próximos e simultaneamente ativos (Cecere et al, 1996;van der Glas et al, 1996), o movimento da cabeça e pescoço, expressões faciais (Lobbezoo et al, 1993;Beck et al, 2004), as condições dolorosas (Jensen, 1999;Wang et al, 2004) e o histórico de bruxismo (Molina et al, 2001;Manfredini et al, 2003).…”

Section: Eletromiografia De Superfície Nas Disfunções Temporomandibul...unclassified

Contribução diagnostica da eletromiografia de superficie para a disfunção temporomandibular

Pedroni¹,

Bérzin²

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Fausto ensina a todos muito mais do que a didática, do que a metodologia e a conduta com a pesquisa. Ensina a enxergar a beleza das coisas e da vida, a exaltar a simplicidade, a fazer com que as conquistas se tornem mais prazerosas e as dificuldades menos árduas. Tive muita sorte de encontrar um homem tão grandioso e sábio que me aceitou e compartilhou tantos ensinamentos valiosos, profissionais e pessoais.Obrigada pela inspiração para o estudo da eletromiografia e pela liberdade de criar, de mudar e de se aventurar no mundo da pesquisa.Seus ensinamentos estarão comigo por toda a vida.

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The effects of bipolar electrode montage on conduction velocity estimation from the surface electromyogram

Cited by 12 publications

References 37 publications

Unchanged muscle fiber conduction velocity relates to mild acidosis during exhaustive bicycling

Unchanged muscle fiber conduction velocity relates to mild acidosis during exhaustive bicycling

The Sensitivity of Bipolar Electromyograms to Muscle Excitation Scales With the Inter-Electrode Distance

Contribução diagnostica da eletromiografia de superficie para a disfunção temporomandibular

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