Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1988-11-15
pubmed:abstractText
We have measured the configurational and firing properties of 13,206 motor unit action potentials (MUAPs) from the brachial biceps, brachial triceps, and anterior tibial muscles in 10 young (20-40 years), 10 middle-aged (40-60 years), and 10 elderly (60-80 years) normal individuals, using an automatic method for decomposition of the electromyographic (EMG) interference pattern (ADEMG). Recording were made during stable isometric contractions at threshold, 10%, and 30% of maximum voluntary contraction using standard concentric needle electrodes. At supra-threshold forces, an average of 5.9 simultaneously active MUAPs were identified at each recording site. Mean amplitudes, durations, and numbers of turns all increased linearly with age in both low-threshold and high-threshold MUAPs (p less than 0.01), suggesting an ongoing process of progressive denervation and compensatory reinnervation. Mean MUAP firing rates decreased with age (p = 0.01) when force was measured proportionately, but not when measured absolutely. In a subgroup of 12 age-matched gender pairs, men had larger mean MUAP amplitudes, rise rates, and numbers of turns (p less than 0.05), probably reflecting larger muscle fiber diameters. These findings amplify previous observations from traditional analysis of lowest-threshold single MUAPs; establish a base of normative adult data for ADEMG; and further validate the clinical applicability of rapid, automatic EMG decomposition.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0364-5134
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
207-13
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Age effects on properties of motor unit action potentials: ADEMG analysis.
pubmed:affiliation
Department of Neurology, Stanford University School of Medicine, CA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't