gms | German Medical Science

14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT)

17.06. - 21.06.2019, Berlin

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Assessment of age-related differences in decomposition-based quantitative electromyography in the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles

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  • presenting/speaker Philemon Tsang - University of Western Ontario, London, Canada
  • Joy MacDermid - University of Western Ontario, London, Canada
  • Thomas Miller - University of Western Ontario, London, Canada
  • Timothy Doherty - University of Western Ontario, London, Canada
  • Christopher Doherty - University of Western Ontario, London, Canada

International Federation of Societies for Surgery of the Hand. International Federation of Societies for Hand Therapy. 14th Triennial Congress of the International Federation of Societies for Surgery of the Hand (IFSSH), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT), 11th Triennial Congress of the International Federation of Societies for Hand Therapy (IFSHT). Berlin, 17.-21.06.2019. Düsseldorf: German Medical Science GMS Publishing House; 2020. DocIFSHT19-1069

doi: 10.3205/19ifssh1490, urn:nbn:de:0183-19ifssh14905

Published: February 6, 2020

© 2020 Tsang et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.

Outline

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Objective: Decomposition-based quantitative electromyography (DQEMG) is one method of measuring neuromuscular changes in human muscles. DQEMG can measure motor unit number estimations (MUNE) and other motor unit properties (i.e. neuromuscular stability). Changes to MUNE and neuromuscular stability have been associated with pathological states such as sarcopenia and diabetic neuropathy. To date there have been no studies investigating the motor unit properties of the ulnar nerve innervated intrinsic hand muscles using DQEMG in a healthy aging population. The objective of the current study is to compare the motor unit physiology of healthy younger (20 to 40-year-old) and older (60 to 80-year-old) adults using DQEMG in the ulnar nerve innervated intrinsic hand muscles.

Materials and Methods: Seven healthy younger adults were tested (Mean Age = 27.7 ± 2.8; 3 Females) and seven healthy older adults were tested (Mean Age = 68.9 ± 3.9; 3 Females). DQEMG was obtained from the first dorsal interosseous (FDI) and the abductor digiti minimi (ADM) to measure the MUNE. Neuromuscular measurements of motor unit potential amplitude and near-fiber (NF) jiggle were also obtained. Independent t-test were performed to evaluate group differences.

Results: MUNE of the FDI were not significantly reduced (p > 0.05) in older adults when compared to younger adults (285 units vs 443 units, respectively). Likewise, MUNE of the ADM muscles were not significantly greater in younger adults vs older adults (272 units vs 259 units, respectively). Motor unit potential amplitude and NF jiggle were not significantly different between younger adults and older adults (p>0.05).

Conclusions: Although a small sample is precluded, a statistical analysis indicates a potentially large effect size in the FDI and a small effect size in the ADM for motor unit loss. A loss of motor units may lead to deficits such as decreases in muscle strength and motor control. The FDI is involved with many hand actions such as pinching and grasping, which play a role in ADLs.