Detecting motor unit abnormalities in amyotrophic lateral sclerosis using high-density surface EMG. Clin Neurophysiol 2022 Oct;142:262-272
Date
07/29/2022Pubmed ID
35902304DOI
10.1016/j.clinph.2022.06.016Scopus ID
2-s2.0-85134824578 (requires institutional sign-in at Scopus site) 26 CitationsAbstract
OBJECTIVE: The purpose of this study was to detect specific motor unit (MU) abnormalities in people with amyotrophic lateral sclerosis (ALS) compared to controls using high-density surface electromyography (HD-SEMG).
METHODS: Sixteen people with ALS and 16 control subjects. The participants performed ramp up and sustained contractions at 30% of their maximal voluntary contraction. HD-SEMG signals were recorded in the vastus lateralis muscle and decomposed into individual MU firing behavior using a convolution blind source separation method.
RESULTS: In total, 339 MUs were detected (people with ALS; n = 93, control subjects; n = 246). People with ALS showed significantly higher mean firing rate, recruitment threshold, coefficient of variation of the MU firing rate, MU firing rate at recruitment, and motoneurons excitability than those of control subjects (p < 0.001). The number of MU, MU firing rate, recruitment threshold, and MU firing rate at recruitment were significantly correlated with disease severity (p < 0.001). Multivariable analysis revealed that an increased MU firing rate at recruitment was independently associated with ALS.
CONCLUSIONS: These results suggest increased excitability at recruitment, which is consistent with neurodegeneration results in a compensatory increase in MU activity.
SIGNIFICANCE: Abnormal MU firing behavior provides an important physiological index for understanding the pathophysiology of ALS.
Author List
Nishikawa Y, Holobar A, Watanabe K, Takahashi T, Ueno H, Maeda N, Maruyama H, Tanaka S, Hyngstrom ASAuthor
Allison Hyngstrom PhD Associate Professor in the Physical Therapy department at Marquette UniversityMESH terms used to index this publication - Major topics in bold
Action PotentialsAmyotrophic Lateral Sclerosis
Electromyography
Humans
Isometric Contraction
Motor Neurons
Muscle, Skeletal
Recruitment, Neurophysiological