TY - JOUR
T1 - Increased Single-Fiber Jitter Level Is Associated with Reduction in Motor Function with Aging
AU - Chung, Tae
AU - Tian, Yanli
AU - Walston, Jeremy
AU - Hoke, Ahmet
N1 - Funding Information:
This study was supported by RMSTP K12 grant (5K12HD001097-19), the Dr. Miriam and Sheldon G Adelson Medical Research Foundation, the National Institutes on Aging (NIA) (R21-AG025143), and the Johns Hopkins Older Americans Independence Center (P30-AG021334). Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s Web site (www.ajpmr.com). Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. ISSN: 0894-9115 DOI: 10.1097/PHM.0000000000000915
PY - 2018/8/1
Y1 - 2018/8/1
N2 - Objective Age-associated skeletal muscle weakness is a major contributing factor to an increased late life mortality and morbidity, but its neurobiology is poorly understood. Previously, we provided histological evidence of dying-back axonal degeneration of motor neurons and denervation of neuromuscular junctions in age-associated muscle weakness. Given this, we aimed to evaluate the relation between impaired neuromuscular transmission and various aspects of age-associated muscle weakness. Design We compared two electrophysiological measures, single-fiber jitter and compound motor action potential in mice of different age groups, and correlated them with various physical performance measures, such as grip strength, standing and walking time, and treadmill performance. Results Consistent with our previous histological data, single-fiber jitter, a measure of neuromuscular junction transmission, was significantly increased in older animals, whereas compound motor action potential shows no difference between young and old age groups. Neither jitter nor compound motor action potential correlated with any of physical performance measures, except for jitter and standing activity. Conclusions Impaired neuromuscular transmission-represented as increase in single-fiber electromyography jitter level-reflects decline in motor function with aging.
AB - Objective Age-associated skeletal muscle weakness is a major contributing factor to an increased late life mortality and morbidity, but its neurobiology is poorly understood. Previously, we provided histological evidence of dying-back axonal degeneration of motor neurons and denervation of neuromuscular junctions in age-associated muscle weakness. Given this, we aimed to evaluate the relation between impaired neuromuscular transmission and various aspects of age-associated muscle weakness. Design We compared two electrophysiological measures, single-fiber jitter and compound motor action potential in mice of different age groups, and correlated them with various physical performance measures, such as grip strength, standing and walking time, and treadmill performance. Results Consistent with our previous histological data, single-fiber jitter, a measure of neuromuscular junction transmission, was significantly increased in older animals, whereas compound motor action potential shows no difference between young and old age groups. Neither jitter nor compound motor action potential correlated with any of physical performance measures, except for jitter and standing activity. Conclusions Impaired neuromuscular transmission-represented as increase in single-fiber electromyography jitter level-reflects decline in motor function with aging.
KW - Aging
KW - Axon
KW - Dying-Back
KW - Electrophysiology
KW - Frailty
KW - Neuromuscular Junction
KW - Sarcopenia
KW - Single-Fiber Electromyography
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U2 - 10.1097/PHM.0000000000000915
DO - 10.1097/PHM.0000000000000915
M3 - Article
C2 - 29498943
AN - SCOPUS:85050100169
VL - 97
SP - 551
EP - 556
JO - American Journal of Physical Medicine and Rehabilitation
JF - American Journal of Physical Medicine and Rehabilitation
SN - 0894-9115
IS - 8
ER -