Decomposition‐based quantitative electromyography: Effect of force on motor unit potentials and motor unit number estimates

Decomposition‐based quantitative electromyography (DQEMG) allows for the collection of motor unit potentials (MUPs) over a broad range of force levels. Given the size principle of motor unit recruitment, it may be necessary to control for force when using DQEMG for the purpose of deriving a motor unit number estimate (MUNE). Therefore, this study was performed to examine the effect of force on the physiological characteristics of concentric needle‐ and surface‐detected MUPs and the subsequent impact on MUNEs obtained from the first dorsal interosseous (FDI) muscle sampled using DQEMG. Maximum M waves were elicited in 10 subjects with supramaximal stimulation of the ulnar nerve at the wrist. Intramuscular and surface‐detected EMG signals were collected simultaneously during 30‐s voluntary isometric contractions performed at specific percentages of maximal voluntary contraction (MVC). Decomposition algorithms were used to identify needle‐detected MUPs and their individual MU firing times. These MU firing times were used as triggers to extract their corresponding surface‐detected MUPs (S‐MUPs) using spike‐triggered averaging. A mean S‐MUP was then calculated, the size of which was divided into the maximum M‐wave size to derive a MUNE. Increased levels of contraction had a significant effect on needle‐ and surface‐detected MUP size, firing rate, and MUNE. These results suggest that force level is an important factor to consider when performing quantitative EMG, including MUNEs with this method. Muscle Nerve, 2005

[1]  R B Stein,et al.  The orderly recruitment of human motor units during voluntary isometric contractions , 1973, The Journal of physiology.

[2]  J Perry,et al.  EMG-force relationships in skeletal muscle. , 1981, Critical reviews in biomedical engineering.

[3]  T J Doherty,et al.  A method for the longitudinal study of human thenar motor units , 1994, Muscle & nerve.

[4]  D. Stashuk,et al.  Decomposition‐based quantitative electromyography: Methods and initial normative data in five muscles , 2003, Muscle & nerve.

[5]  H. Clamann,et al.  Elsevier/North-Holland Biomedical Press COMPARISON OF THE RECRUITMENT AND DISCHARGE PROPERTIES OF MOTOR UNITS IN H U M A N BRACHIAL BICEPS AND A D D U C T O R POLLICIS D U R I N G ISOMETRIC CONTRACTIONS , 2018 .

[6]  Catherine Lomen-Hoerth,et al.  Statistical motor unit number estimation: From theory to practice , 2003, Muscle & nerve.

[7]  W. Brown,et al.  The estimated numbers and relative sizes of thenar motor units as selected by multiple point stimulation in young and older adults , 1993, Muscle & nerve.

[8]  M. Rubin.  Neuromuscular Function and Disease: Basic, Clinical, and Electrodiagnostic Aspects , 2002 .

[9]  Daniel W Stashuk,et al.  Motor unit number estimation by decomposition‐enhanced spike‐triggered averaging: Control data, test–retest reliability, and contractile level effects , 2004, Muscle & nerve.

[10]  D. Winter,et al.  Models of recruitment and rate coding organization in motor-unit pools. , 1993, Journal of neurophysiology.

[11]  D Stashuk,et al.  EMG signal decomposition: how can it be accomplished and used? , 2001, Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology.

[12]  F BUCHTHAL,et al.  Action potential parameters in normal human muscle and their dependence on physical variables. , 1954, Acta physiologica Scandinavica.

[13]  F. Buchthal,et al.  Motor unit territory in different human muscles. , 1959, Acta physiologica Scandinavica.

[14]  K. Seki,et al.  Firing rate modulation of human motor units in different muscles during isometric contraction with various forces , 1996, Brain Research.

[15]  K. McGill,et al.  Automatic decomposition electromyography (ADEMG): validation and normative data in brachial biceps. , 1985, Electroencephalography and clinical neurophysiology.

[16]  C. J. Luca.  Control properties of motor units , 1985 .

[17]  D W Stashuk,et al.  Decomposition and quantitative analysis of clinical electromyographic signals. , 1999, Medical engineering & physics.

[18]  E Stålberg,et al.  Macro EMG, a new recording technique. , 1980, Journal of neurology, neurosurgery, and psychiatry.

[19]  Charles F. Bolton,et al.  Neuromuscular function and disease : Basic, clinical, and electrodiagnostic aspects , 2002 .

[20]  E Stålberg,et al.  Quantitative motor unit potential analysis. , 1996, Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society.

[21]  S D Nandedkar,et al.  Analysis of amplitude and area of concentric needle EMG motor unit action potentials. , 1988, Electroencephalography and clinical neurophysiology.

[22]  E Stålberg,et al.  Macro EMG in healthy subjects of different ages. , 1982, Journal of neurology, neurosurgery, and psychiatry.

[23]  R. Conwit,et al.  The relationship of motor unit size, firing rate and force , 1999, Clinical Neurophysiology.

[24]  F. Buchthal,et al.  Multielectrode study of the territory of a motor unit. , 1957, Acta physiologica Scandinavica.

[25]  B. Bigland-ritchie,et al.  Linear and non-linear surface EMG/force relationships in human muscles. An anatomical/functional argument for the existence of both. , 1983, American journal of physical medicine.

[26]  K. McGill,et al.  Influence of contractile force on properties of motor unit action potentials: ADEMG analysis , 1988, Journal of the Neurological Sciences.

[27]  Carlo J. Deluc.  CONTROL PROPERTIES OF MOTOR UNITS , 1985 .

[28]  J. Wertsch,et al.  Quantitative electromyography. , 2003, Physical medicine and rehabilitation clinics of North America.

[29]  F BUCHTHAL,et al.  Action potential parameters in normal human muscle and their physiological determinants. , 1954, Acta physiologica Scandinavica.

[30]  Brian Tracy,et al.  Decomposition‐enhanced spike‐triggered averaging: Contraction level effects , 1997, Muscle & nerve.