Increased Single-Fiber Jitter Level Is Associated with Reduction in Motor Function with Aging

Research output: Contribution to journalArticlepeer-review

Abstract

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.

Original languageEnglish (US)
Pages (from-to)551-556
Number of pages6
JournalAmerican Journal of Physical Medicine and Rehabilitation
Volume97
Issue number8
DOIs
StatePublished - Aug 1 2018

Keywords

  • Aging
  • Axon
  • Dying-Back
  • Electrophysiology
  • Frailty
  • Neuromuscular Junction
  • Sarcopenia
  • Single-Fiber Electromyography

ASJC Scopus subject areas

  • Physical Therapy, Sports Therapy and Rehabilitation
  • Rehabilitation

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