Name: cmap scan mune (mscan) - a novel motor unit number estimation (mune) method
Uploaded: 2018-06-07T12:30:00
Description: Watch this Scientific Journal Video about CMAP Scan MUNE MScan - A Novel Motor Unit Number Estimation MUNE Method at JoVE.com

This study was financially supported mainly by the Lundbeck Foundation.
Additionally, Knud og Edith Eriksens Mindefond, S&#248;ster og Verner Lipperts Fond, Fonden til L&#230;gevidenskabens Fremme, and Aage og Johanne Louis Hansens Fond supported this study.

All subjects must give their written consent prior to examination, and the recording protocol must be approved by the appropriate local ethical review board(s). All methods described here were approved by the Regional Scientific Ethical Committee and the Danish Data Protection Agency.
Note: The recordings are made with the &#8220;TRONDNF&#8221; recording protocol, which is a part of the software (see the Table of Materials). Other equipment used is a bipolar s...

<ol>
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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bayesian+statistical+MUNE+method.">Bayesian statistical MUNE method.</a> Muscle Nerve. 36, 206-213 (2007).</li><li>Ridall, P. G., Pettitt, A. N., Henderson, R. D., McCombe, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Motor+unit+number+estimation--a+Bayesian+approach.">Motor unit number estimation--a Bayesian approach.</a> Biometrics. 62, 1235-1250 (2006).</li><li>Nandedkar, S. D., Nandedkar, D. S., Barkhaus, P. E., Stalberg, E. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Motor+unit+number+index+(MUNIX).">Motor unit number index (MUNIX).</a> IEEE Trans. Biomed. 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B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reproducibility,+and+sensitivity+to+motor+unit+loss+in+amyotrophic+lateral+sclerosis,+of+a+novel+MUNE+method:+MScanFit+MUNE.">Reproducibility, and sensitivity to motor unit loss in amyotrophic lateral sclerosis, of a novel MUNE method: MScanFit MUNE.</a> Clin neurophysiol. 128, 1380-1388 (2017).</li><li>Maathuis, E. M., Drenthen, J., Visser, G. H., Blok, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reproducibility+of+the+CMAP+scan.">Reproducibility of the CMAP scan.</a> J. Electromyogr. Kinesiol. 21, 433-437 (2011).</li><li>Sleutjes, B. T. H. 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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparing+the+areas+under+two+or+more+correlated+receiver+operating+characteristic+curves:+a+nonparametric+approach.">Comparing the areas under two or more correlated receiver operating characteristic curves: a nonparametric approach.</a> Biometrics. 44, 837-845 (1988).</li><li>Hanley, J. A., McNeil, B. 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Critical steps within the protocol: MScan is a highly automated procedure, but as with all EMG methods, care should be taken to obtain consistent results. In the preparation stage, it is important to achieve relaxation, since spontaneous activity or movement artefacts during the CMAP scan introduce spurious variance in the CMAP and confound the generation of the preliminary model.
Modifications and troubleshooting: We found that taping of the fingers, and use ...

Motor system movement is dependent on the motor unit, which refers to an individual motor nerve fiber together with the muscle fibers it activates, and motor unit number is the number of anterior horn cells or axons innervating a single muscle1. During the denervation and reinnervation processes, healthy axons take over the role of axons that are lost by collateral sprouting. Therefore, compound muscle action potential (CMAP) amplitude does not give the necessary information about the degree of motor unit loss. CMAP amplitude may only start to fall when more than 50% of motor units are lost. Similarly, the magnitude of abnormal spontaneous activity or motor unit potential (MUP) changes does not correlate with the degree of denervation.
Overall, there is no electrophysiological technique that allows for simple, direct measurements of motor unit number. Instead, an estimate of motor unit number (MUNE) is used to assess lower motor neuron loss2. Several MUNE methods have been developed since the implementation of the first method, incremental stimulation MUNE, which was introduced in 1971 by McComas3. Most methods have been based on measuring several surface-recorded motor unit potentials (sMUP) and dividing the maximal CMAP by the average sMUP amplitude. Such methods include incremental stimulation4, multiple point stimulation (MPS)5, and spike-triggered averaging6. Other MUNE methods have used statistical techniques based on the probabilistic nature of the firing of a motor unit in response to a stimulus7,8,9,10. This variability means that firing different combinations of motor units leads to variability in the size of the CMAP responses. Motor unit number index (Munix) is a more recently introduced method, which uses the surface interference patterns recorded during voluntary contractions to estimate the average size of sMUP11,12.
These MUNE methods all suffer from one or more limitations, such as the presence of subjectivity, dependence on the absolute CMAP amplitude, bias in the selection of units, the long time needed to sample enough units, or the long time required to analyze the results. A new MUNE method has recently been developed, &#39;CMAP scan MUNE` (MScan), to overcome these limitations13. This method avoids the problems inherent in unit selection by taking account of the contribution of all units to the CMAP, as measured in a detailed stimulus-response curve, or CMAP scan14,15. It also avoids the extended analysis time of a similar, model-fitting method9,10, by using new algorithms16. In a recent study, the reproducibility of MScan in estimating the number of motor units was better than two more traditional methods, MPS MUNE and Munix13. Additionally, MScan could show motor unit loss in earlier stages of Amyotrophic Lateral Sclerosis (ALS) than MPS MUNE and Munix. MScan was faster than MPS MUNE and as fast as Munix13.
This paper describes the methodology of MScan in detail. It also summarizes the previously reported intra- and inter-rater reproducibility of MScan in patients with ALS and healthy control subjects13, which may enable the reader to judge whether the method would be appropriate for a planned study.

<table>
	<tbody>
		<tr>
			<td>QtracW software</td>
			<td>Digitimer Ltd (copyright Institute of Neurology, University College, London)&#160;&#160;</td>
			<td>QtracW</td>
			<td></td>
		</tr>
		<tr>
			<td>MScanFit</td>
			<td>Digitimer Ltd (copyright Institute of Neurology, University College, London)&#160;&#160;</td>
			<td>QtracW</td>
			<td></td>
		</tr>
		<tr>
			<td>DS5 bipolar stimulator</td>
			<td>Digitimer Ltd&#160;</td>
			<td>DS5</td>
			<td></td>
		</tr>
		<tr>
			<td>D440 amplifier&#160;</td>
			<td>Digitimer Ltd&#160;</td>
			<td>D440-2 (2 channel) or D440-4 (4 channel)</td>
			<td></td>
		</tr>
		<tr>
			<td>HumBug Noise Eliminator</td>
			<td>Digitimer Ltd&#160;</td>
			<td>Humbug</td>
			<td></td>
		</tr>
		<tr>
			<td>Analogue-to-digital (A/D) board&#160;&#160;</td>
			<td>National Instruments</td>
			<td>NI-6221&#160;</td>
			<td></td>
		</tr>
	</tbody>
</table>

cmap scan mune (mscan) - a novel motor unit number estimation (mune) method

Like other methods for motor unit number estimation (MUNE), compound muscle action potential (CMAP) scan MUNE (MScan) is a non-invasive electrophysiologic method to estimate the number of functioning motor units in a muscle. MUNE is an important tool for the assessment of neuropathies and neuronopathies. Unlike most MUNE methods in use, MScan assesses all the motor units in a muscle, by fitting a model to a detailed stimulus-response curve, or CMAP scan. It thereby avoids the bias inherent in all MUNE methods based on extrapolating from a small sample of units. Like &#39;Bayesian MUNE,&#39;&#160;MScan analysis works by fitting a model, made up of motor units with different amplitudes, thresholds, and threshold variabilities, but the fitting method is quite different, and completed within five minutes, rather than several hours. The MScan off-line analysis works in two stages: first, a preliminary model is generated based on the slope and variance of the points in the scan, and second, this model is then refined by adjusting all the parameters to improve the fit between the original scan and scans generated by the model.
This new method has been tested for reproducibility and recording time on 22 amyotrophic lateral sclerosis (ALS) patients and 20 healthy controls, with each test repeated twice by two blinded physicians. MScan showed excellent intra- and inter-rater reproducibility with ICC values of &#62;0.98 and a coefficient of variation averaging 12.3 &#177; 1.6%. There was no difference in the intra-rater reproducibility between the two observers. Average recording time was 6.27 &#177; 0.27 min.
This protocol describes how to record a CMAP scan and how to use the MScan software to derive an estimate of the number and sizes of the functioning motor units. MScan is a fast, convenient, and reproducible method, which may be helpful in diagnoses and monitoring disease progression in neuromuscular disorders.

The following results were obtained in a recent study, in which the MScan method was compared with two established techniques: multiple point stimulation MUNE (MPS) and motor unit number index (Munix)13. The results show that with the technique described in this protocol, consistent results with excellent reproducibility can be achieved. The method can differentiate ALS patients from healthy controls in an earlier stage of the disease than CMAP and it is quick and ...

Watch this Scientific Journal Video about CMAP Scan MUNE MScan - A Novel Motor Unit Number Estimation MUNE Method at JoVE.com

CMAP Scan MUNE MScan - A Novel Motor Unit Number Estimation MUNE Method

This protocol describes a new method to estimate the number of functioning motor units in a muscle, by fitting a model to a detailed stimulus-response curve of the compound muscle action potential. It is quick and easy to perform and analyze and has excellent reproducibility.

CMAP Scan MUNE (MScan) - A Novel Motor Unit Number Estimation (MUNE) Method

Like other methods for motor unit number estimation (MUNE), compound muscle action potential (CMAP) scan MUNE (MScan) is a non-invasive electrophysiologic ...

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