Preliminary evaluation of the sensitivity to change of DE-STA motor unit number estimation in the upper trapezius muscle in amyotrophic lateral sclerosis

• Published in: Clinical neurophysiology Vol. 126; no. 7; pp. 1427 - 1434
• Main Authors: Ives, Colleen T., Findlater, Karen, Shoesmith, Christen L., Doherty, Timothy J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ireland Ltd 01.07.2015
• Subjects: Action Potentials - physiology; Aged; Amyotrophic lateral sclerosis (ALS); Amyotrophic Lateral Sclerosis - diagnosis; Amyotrophic Lateral Sclerosis - physiopathology; Decomposition-based quantitative electromyography (DQEMG); Decomposition-enhanced spike-triggered averaging (DE-STA); Electromyography - methods; Female; Humans; Longitudinal Studies; Male; Middle Aged; Motor Neurons - pathology; Motor Neurons - physiology; Motor unit number estimation (MUNE); Muscle Strength - physiology; Muscle Strength Dynamometer; Nerve Degeneration - pathology; Nerve Degeneration - physiopathology; Neurology; Outcome Assessment (Health Care); Regression Analysis; Sensitivity to change; Severity of Illness Index; Superficial Back Muscles - innervation; Superficial Back Muscles - physiopathology; Trapezius muscle; Vital Capacity - physiology; Decomposition-enhanced spike-triggered averaging (DE-STA); Sensitivity to change; Motor unit number estimation (MUNE); Trapezius muscle; Decomposition-based quantitative electromyography (DQEMG); Amyotrophic lateral sclerosis (ALS)
• ISSN: 1388-2457; 1872-8952; 1872-8952
• DOI: 10.1016/j.clinph.2014.10.013

•Decomposition-enhanced spike-triggered averaging (DE-STA) motor unit number estimation (MUNE) demonstrated a moderate degree of sensitivity to change in subjects with amyotrophic lateral sclerosis (ALS).•Variability in the results of DE-STA MUNE between time points indicates a need for future investigation regarding potential sources of error associated with the technique.•This study has established the feasibility of the longitudinal application of DE-STA MUNE to the upper trapezius muscle in ALS. To compare the sensitivity to change of decomposition-enhanced spike-triggered averaging (DE-STA) motor unit number estimation (MUNE) in the upper trapezius (UT) to that of various clinical outcome measures in subjects with amyotrophic lateral sclerosis (ALS). Ten patients with clinically probable or definite ALS were assessed at baseline, 2, 4 and 6months with the following outcome measures: manual muscle testing in five upper extremity muscle groups, scapular elevation and elbow flexion peak force measured with hand-held dynamometry, MUNE, forced vital capacity and the Revised ALS Functional Rating Scale (ALSFRS-R). ALSFRS-R was the only outcome measure for which there was a significant difference between baseline and 6months (p=0.034). ALSFRS-R had the largest standardized response mean (SRM), and was thus the most sensitive to change. MUNE demonstrated a decline over 6months and a moderate SRM (−0.63). This study has demonstrated a moderate degree of sensitivity to change for DE-STA MUNE as applied to the UT in subjects with ALS. In this preliminary study, DE-STA MUNE detected motor unit loss over 6months, with a moderate degree of sensitivity, in the upper trapezius of subjects with ALS.