Mathew Piasecki1, Oscar Garnés-Camarena2, Daniel W Stashuk3. 1. Clinical, Metabolic and Molecular Physiology, MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, University of Nottingham, Nottingham, United Kingdom. Electronic address: mathew.piasecki@nottingham.ac.uk. 2. Department of Physical Medicine and Rehabilitation - Clinical Neurophysiology, Jiménez Díaz Foundation University Hospital, Madrid, Spain. 3. Department of Systems Design Engineering, University of Waterloo, Ontario, Canada.
Abstract
OBJECTIVE: Describe and evaluate the concepts of near fiber electromyography (NFEMG), the features used, including near fiber motor unit potential (NFMUP) duration and dispersion, which relate to motor unit distal axonal branch and muscle fiber conduction time dispersion, and NFMUP segment jitter, a new measure of the temporal variability of neuromuscular junction transmission (NMJ), and axonal branch and muscle fibre conduction for the near fibres (i.e. NF jitter), and the methods for obtaining their values. METHODS: Trains of high-pass filtered motor unit potentials (MUPs) (i.e. NFMUP trains) were extracted from needle-detected EMG signals to assess changes in motor unit (MU) morphology and electrophysiology caused by neuromuscular disorders or ageing. Evaluations using simulated needle-detected EMG data were completed and example human data are presented. RESULTS: NFEMG feature values can be used to detect axonal sprouting, conduction slowing and NMJ transmission delay as well as changes in MU fiber diameter variability, and NF jitter. These changes can be detected prior to alterations of MU size or numbers. CONCLUSIONS: The evaluations clearly demonstrate and the example data support that NFMUP duration and dispersion reflect MU distal axonal branching, conduction slowing and NMJ transmission delay and/or MU fiber diameter variability and that NFMUP jiggle and segment jitter reflect NF jitter. SIGNIFICANCE: NFEMG can detect early changes in MU morphology and/or electrophysiology and has the potential to augment clinical diagnosis and tracking of neuromuscular disorders.
OBJECTIVE: Describe and evaluate the concepts of near fiber electromyography (NFEMG), the features used, including near fiber motor unit potential (NFMUP) duration and dispersion, which relate to motor unit distal axonal branch and muscle fiber conduction time dispersion, and NFMUP segment jitter, a new measure of the temporal variability of neuromuscular junction transmission (NMJ), and axonal branch and muscle fibre conduction for the near fibres (i.e. NF jitter), and the methods for obtaining their values. METHODS: Trains of high-pass filtered motor unit potentials (MUPs) (i.e. NFMUP trains) were extracted from needle-detected EMG signals to assess changes in motor unit (MU) morphology and electrophysiology caused by neuromuscular disorders or ageing. Evaluations using simulated needle-detected EMG data were completed and example human data are presented. RESULTS:NFEMG feature values can be used to detect axonal sprouting, conduction slowing and NMJ transmission delay as well as changes in MU fiber diameter variability, and NF jitter. These changes can be detected prior to alterations of MU size or numbers. CONCLUSIONS: The evaluations clearly demonstrate and the example data support that NFMUP duration and dispersion reflect MU distal axonal branching, conduction slowing and NMJ transmission delay and/or MU fiber diameter variability and that NFMUP jiggle and segment jitter reflect NF jitter. SIGNIFICANCE: NFEMG can detect early changes in MU morphology and/or electrophysiology and has the potential to augment clinical diagnosis and tracking of neuromuscular disorders.
Authors: Yuxiao Guo; Jessica Piasecki; Agnieszka Swiecicka; Alex Ireland; Bethan E Phillips; Philip J Atherton; Daniel Stashuk; Martin K Rutter; Jamie S McPhee; Mathew Piasecki Journal: Geroscience Date: 2021-12-03 Impact factor: 7.581
Authors: Yuxiao Guo; Eleanor J Jones; Thomas B Inns; Isabel A Ely; Daniel W Stashuk; Daniel J Wilkinson; Kenneth Smith; Jessica Piasecki; Bethan E Phillips; Philip J Atherton; Mathew Piasecki Journal: Acta Physiol (Oxf) Date: 2022-03-02 Impact factor: 7.523
Authors: Isabel A Ely; Eleanor J Jones; Thomas B Inns; Síobhra Dooley; Sarah B J Miller; Daniel W Stashuk; Philip J Atherton; Bethan E Phillips; Mathew Piasecki Journal: Exp Physiol Date: 2022-08-12 Impact factor: 2.858