Lower motor neuron involvement in ALS assessed by motor unit number index (MUNIX): Long-term changes and reproducibility

Fathi, Davood; Mohammadi, Bahram; Dengler, Reinhard; Böselt, Sebastian; Petri, Susanne; Kollewe, Katja

doi:10.1016/j.clinph.2015.12.023

Cited by 45 publications

(46 citation statements)

References 27 publications

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“…Clear differences between the mean-MUNIX and the single-MUNIX were identified. In a third study (Fathi et al, 2016), two MUNIX measurements were performed on the same day by the same operator (interval less than 30 minutes) on two muscles. The coefficient of variation, defined as the percentage ratio of absolute difference between two measurements over the mean, reached up to 30% in certain muscles.…”

Section: Discussionmentioning

confidence: 99%

“…As a new technique, MUNIX has been assessed for reliability in both healthy subjects (Ahn et al, 2010, Nandedkar et al, 2010, Neuwirth et al, 2011, Kaya et al, 2014, Escorcio-Bezerra et al, 2016) and patients with neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS) (Ahn et al, 2010, Nandedkar et al, 2010, 2011, Fathi et al, 2016). Current studies are mainly focused on the agreement between two (or more) sets of measurements under different conditions such as two visits separated by weeks or months, or on the same condition by different operators (inter-rater reliability).…”

Section: Introductionmentioning

confidence: 99%

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Improving the repeatability of Motor Unit Number Index (MUNIX) by introducing additional epochs at low contraction levels

Peng

Zhang

2017

Clinical Neurophysiology

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Objective To evaluate the repeatability of (Motor Unit Number Index) MUNIX under repeatability conditions, specify the origin of variations and provide strategies for quality control. Methods MUNIX calculations were performed on the bicep brachii muscles of eight healthy subjects. Negative effect of suboptimal electrode positions on MUNIX accuracy was eliminated by employing the high-density surface electromyography technique. MUNIX procedures that utilized a variety of surface interferential pattern (SIP) epoch recruitment strategies (including the original MUNIX procedure, two proposed improvement strategies and their combinations) were described. For each MUNIX procedure, ten thousands of different SIP pools were constructed by randomly recruiting necessary SIP epochs from a large SIP epoch pool (3 datasets, 9 independent electromyography recordings at different contraction levels per dataset and 10 SIP epochs per recording) and implemented for MUNIX calculation. The repeatability of each MUNIX procedure was assessed by summarizing the resulting MUNIX distribution and compared to investigate the effect of SIP epoch selection strategy on repeatability performance. Results SIP epochs selected at lower contraction levels have a stronger influence on the repeatability of MUNIX than those selected at higher contraction levels. MUNIX under repeatability conditions follows a normal distribution and the standard deviation can be significantly reduced by introducing more epochs near the MUNIX definition line. Conclusions The MUNIX technique shows an inherent variation attributable to SIP epochs at low contraction levels. It is recommended that more epochs should be sampled at these low contraction levels to improve the repeatability. Significance The present study thoroughly documented the inherent variation of MUNIX and the causes, and offered practical solutions to improve the repeatability of MUNIX.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improving the repeatability of Motor Unit Number Index (MUNIX) by introducing additional epochs at low contraction levels

Peng

Zhang

2017

Clinical Neurophysiology

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“…Recently longer-term studies using MUNIX have being performed, with extension of the technique to the tibialis anterior and trapezius muscles, and to earlier stages of disease [50][51][52][53][54]. Standardization across multiple centers has been published where 6 proximal and distal muscles were assessed over 15 months from 3 different centers [55].…”

Section: Munixmentioning

confidence: 99%

Assessment of Motor Units in Neuromuscular Disease

Henderson

McCombe

2017

Neurotherapeutics

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“…A useful non-invasive biomarker for ALS progression should anticipate disease severity in advance, be broadly applicable independent of genetic background, and should provide a basis for therapeutic intervention. Many biomarkers in development currently are potentially limited because they are phenomenological including electrophysiological [14], imaging [19], clinical [41] and fluid-based [29] measures. Other upstream markers are specific to relatively rare genetic variants e.g.…”

Section: Introductionmentioning

confidence: 99%

A data-driven approach links microglia to pathology and prognosis in amyotrophic lateral sclerosis

Cooper‐Knock

Green

Altschuler

et al. 2017

acta neuropathol commun

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Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease that lacks a predictive and broadly applicable biomarker. Continued focus on mutation-specific upstream mechanisms has yet to predict disease progression in the clinic. Utilising cellular pathology common to the majority of ALS patients, we implemented an objective transcriptome-driven approach to develop noninvasive prognostic biomarkers for disease progression. Genes expressed in laser captured motor neurons in direct correlation (Spearman rank correlation, p < 0.01) with counts of neuropathology were developed into co-expression network modules. Screening modules using three gene sets representing rate of disease progression and upstream genetic association with ALS led to the prioritisation of a single module enriched for immune response to motor neuron degeneration. Genes in the network module are important for microglial activation and predict disease progression in genetically heterogeneous ALS cohorts: Expression of three genes in peripheral lymphocytes - LILRA2, ITGB2 and CEBPD – differentiate patients with rapid and slowly progressive disease, suggesting promise as a blood-derived biomarker. TREM2 is a member of the network module and the level of soluble TREM2 protein in cerebrospinal fluid is shown to predict survival when measured in late stage disease (Spearman rank correlation, p = 0.01). Our data-driven systems approach has, for the first time, directly linked microglia to the development of motor neuron pathology. LILRA2, ITGB2 and CEBPD represent peripherally accessible candidate biomarkers and TREM2 provides a broadly applicable therapeutic target for ALS.Electronic supplementary materialThe online version of this article (doi:10.1186/s40478-017-0424-x) contains supplementary material, which is available to authorized users.

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Lower motor neuron involvement in ALS assessed by motor unit number index (MUNIX): Long-term changes and reproducibility

Cited by 45 publications

References 27 publications

Improving the repeatability of Motor Unit Number Index (MUNIX) by introducing additional epochs at low contraction levels

Improving the repeatability of Motor Unit Number Index (MUNIX) by introducing additional epochs at low contraction levels

Assessment of Motor Units in Neuromuscular Disease

A data-driven approach links microglia to pathology and prognosis in amyotrophic lateral sclerosis

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