| 1. |
- Chan, Young, et al.
(författare)
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Reinnervation as measured by the motor unit size index is associated with preservation of muscle strength in amyotrophic lateral sclerosis, but not all muscles reinnervate
- 2022
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Ingår i: Muscle and Nerve. - : John Wiley & Sons. - 0148-639X .- 1097-4598. ; 65:2, s. 203-210
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Tidskriftsartikel (refereegranskat)abstract
- Introduction/Aims: The motor unit size index (MUSIX) may provide insight into reinnervation patterns in diseases such as amyotrophic lateral sclerosis (ALS). However, it is not known whether MUSIX detects clinically relevant changes in reinnervation, or if all muscles manifest changes in MUSIX in response to reinnervation after motor unit loss.Methods: Fifty-seven patients with ALS were assessed at 3-month intervals for 12 months in four centers. Muscles examined were abductor pollicis brevis, abductor digiti minimi, biceps brachii, and tibialis anterior. Results were split into two groups: muscles with increases in MUSIX and those without increases. Longitudinal changes in MUSIX, motor unit number index (MUNIX), compound muscle action potential amplitude, and Medical Research Council strength score were investigated.Results: One hundred thirty-three muscles were examined. Fifty-nine percent of the muscles exhibited an increase in MUSIX during the study. Muscles with MUSIX increases lost more motor units (58% decline in MUNIX at 12 months, P <.001) than muscles that did not increase MUSIX (34.6% decline in MUNIX at 12 months, P <.001). However, longitudinal changes in muscle strength were similar. When motor unit loss was similar, the absence of a MUSIX increase was associated with a significantly greater loss of muscle strength (P =.002).Discussion: MUSIX increases are associated with greater motor unit loss but relative preservation of muscle strength. Thus, MUSIX appears to be measuring a clinically relevant response that can provide a quantitative outcome measure of reinnervation in clinical trials. Furthermore, MUSIX suggests that reinnervation may play a major role in determining the progression of weakness.
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| 2. |
- Nandedkar, Sanjeev D., et al.
(författare)
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Motor unit number index : Guidelines for recording signals and their analysis
- 2018
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 58:3, s. 374-380
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: This study proposes guidelines for motor unit number index (MUNIX) recording and analysis. Methods: MUNIX was measured in control participants and in patients with amyotrophic lateral sclerosis. Changes in MUNIX values due to E1 electrode position, number of surface electromyography interference pattern (SIP) epochs, SIP epoch duration, force of contraction, and outlier data points were investigated. Results: MUNIX depends on optimized compound muscle action potential (CMAP) amplitude. Individual muscles showed variations when the number of epochs was low or when the SIP duration was short. Longer SIP duration allowed better recognition of artifacts. MUNIX results were affected by SIP values at all force levels but was more affected when SIP area was low. Discussion: We recommend changing the E1 electrode position to maximize CMAP amplitude. Twenty or more SIP signals of 500-ms duration should be recorded by using force levels ranging from slight to maximum. Traces should be reviewed to identify and exclude signals with tremor or solitary spikes.
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| 3. |
- Neuwirth, Christoph, et al.
(författare)
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Motor Unit Number Index (MUNIX) : A novel neurophysiological technique to follow disease progression in amyotrophic lateral sclerosis
- 2010
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 42:3, s. 379-384
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Tidskriftsartikel (refereegranskat)abstract
- Motor unit number estimation techniques in amyotrophic lateral sclerosis (ALS) patients are technically challenging and time-consuming. The Motor Unit Number Index (MUNIX) is a novel technique based on surface-EMG recordings and requires only 3-5 minutes per muscle. The objective was to explore the feasibility of longitudinal MUNIX measurements in ALS patients. In seven patients enrolled in a clinical trial, eight muscles were studied every 2 months for up to 15 months in addition to the revised ALS-functional rating scale, slow vital capacity, and compound muscle action potentials. The method was well tolerated and easy to perform. Initial MUNIX measures were significantly reduced compared to controls (487 +/- 194 vs. 1459 113; P < 0.001). Relative drop from baseline paralleled the clinical course and was greater than the drop of other markers of disease progression. MUNIX measurements in multiple muscles are suitable for serial neurophysiologic investigations in ALS. Further longitudinal data are needed for reliability validation.
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