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Reliability of the biceps brachii M-wave
Kristina M Calder1, Lesley-Ann Hall, Steve M Lester
1Electromyographic Kinesiology Laboratory, Faculty of Applied Helath Science, Brock University, 500 Glenridge Avenue, St. Catharines, Ontario, L2S 3A1 Canader. calderkristina@hotmail.com
Journal of Neuroengineering and Rehabilitation
|December 8, 2005
Summary
The peak-to-peak amplitude and negative phase area of the biceps brachii M-wave show high reliability for use in H-reflex studies and motor unit number estimation (MUNE). These findings support their use as methodological controls and normalization factors in electromyography (EMG) research.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Physiology
Background:
- The M-wave's peak-to-peak amplitude and negative phase area are crucial for H-reflex studies, motor unit number estimation (MUNE), and electromyography (EMG) normalization.
- Current methodologies often assume minimal M-wave variability without sufficient evidence.
Purpose of the Study:
- To investigate the intraclass reliability of M-wave peak-to-peak amplitude and negative phase area in the biceps brachii muscle.
- To provide evidence for the stability and reproducibility of these measures for methodological controls and normalization factors.
Main Methods:
- Twenty-two healthy adults underwent electrical stimulation of the musculocutaneous nerve over five separate days.
- Fifty trials were analyzed using repeated measures ANOVA for group mean stability and intraclass correlation coefficient (ICC) for individual consistency.
- Variance ratio (VR) assessed the reproducibility of the M-wave shape within subjects.
Main Results:
- The peak-to-peak amplitude showed high consistency (ICC = 0.98) and stable group means.
- The negative phase area also demonstrated high consistency (ICC = 0.96) and stability.
- The M-wave shape was found to be highly reproducible within individuals (VR = 0.244 +/- 0.169).
Conclusions:
- The peak-to-peak amplitude of the maximum M-wave is reliable for use as a methodological control in H-reflex studies and as a normalization factor for voluntary EMG.
- The negative phase area of the maximum M-wave is stable and consistent, and its reproducible waveform shape supports its use in MUNE procedures.