Name: muscle velocity recovery cycles to examine muscle membrane properties
Uploaded: 2020-02-19T14:00:00
Description: Watch this Scientific Journal Video about Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties at JoVE.com

This study was financially supported mainly by the two grants from Lundbeck Foundation (Grant number R191-2015-931 and Grant number R290-2018-751). Additionally, the study was financially supported by Novo Nordisk Foundation Challenge Programme (Grant number NNF14OC0011633) as part of the International Diabetic Neuropathy Consortium.

All subjects must provide written consent prior to examination, and the protocol must be approved by the appropriate local ethical review board. All methods described here were approved by the Regional Scientific Ethical Committee and Danish Data Protection Agency.
1. Preparation of the subject
<ol>
	<li>Assess subjects&#39; medical histories to ensure that they do not have any previous nervous system disorders other than the disease group that will be investigated.</li>
	<li>Inform the subj...

<ol>
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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validity+of+multi-fiber+muscle+velocity+recovery+cycles+recorded+at+a+single+site+using+submaximal+stimuli.">Validity of multi-fiber muscle velocity recovery cycles recorded at a single site using submaximal stimuli.</a> Clinical Neurophysiology. 123 (11), 2296-2305 (2012).</li><li>Z'Graggen, W. J., Troller, R., Ackermann, K. A., Humm, A. M., Bostock, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Velocity+recovery+cycles+of+human+muscle+action+potentials:+repeatability+and+variability.">Velocity recovery cycles of human muscle action potentials: repeatability and variability.</a> Clinical Neurophysiology. 122 (11), 2294-2299 (2011).</li><li>Lee, J. H. F., Boland-Freitas, R., Ng, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sarcolemmal+excitability+changes+in+normal+human+aging.">Sarcolemmal excitability changes in normal human aging.</a> Muscle and Nerve. 57 (6), 981-988 (2018).</li><li>Lee, J. H. F., Boland-Freitas, R., Ng, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+differences+in+sarcolemmal+excitability+between+human+muscles.">Physiological differences in sarcolemmal excitability between human muscles.</a> Muscle and Nerve. 60 (4), 433-436 (2019).</li><li>Humm, A. M., Bostock, H., Troller, R., Z'Graggen, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Muscle+ischaemia+in+patients+with+orthostatic+hypotension+assessed+by+velocity+recovery+cycles.">Muscle ischaemia in patients with orthostatic hypotension assessed by velocity recovery cycles.</a> Journal of Neurology, Neurosurgery and Psychiatry. 82 (12), 1394-1398 (2011).</li><li>Z'Graggen, W. J., 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=Velocity+recovery+cycles+of+human+muscle+action+potentials+in+chronic+renal+failure.">Velocity recovery cycles of human muscle action potentials in chronic renal failure.</a> Clinical Neurophysiology. 121 (6), 874-881 (2010).</li><li>Z'Graggen, W. J., 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=Muscle+membrane+dysfunction+in+critical+illness+myopathy+assessed+by+velocity+recovery+cycles.">Muscle membrane dysfunction in critical illness myopathy assessed by velocity recovery cycles.</a> Clinical Neurophysiology. 122 (4), 834-841 (2011).</li><li>Lee, J. H., Boland-Freitas, R., Liang, C., Ng, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sarcolemmal+depolarization+in+sporadic+inclusion+body+myositis+assessed+with+muscle+velocity+recovery+cycles.">Sarcolemmal depolarization in sporadic inclusion body myositis assessed with muscle velocity recovery cycles.</a> Clinical Neurophysiology. 19 (31205-2), 1388 (2019).</li><li>Tan, S. V., Z'Graggen, W. J., Hanna, M. G., Bostock, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+assessment+of+muscle+membrane+properties+in+the+sodium+channel+myotonias.">In vivo assessment of muscle membrane properties in the sodium channel myotonias.</a> Muscle and Nerve. 57 (4), 586-594 (2018).</li><li>Tan, S. V., 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=In+vivo+assessment+of+muscle+membrane+properties+in+myotonic+dystrophy.">In vivo assessment of muscle membrane properties in myotonic dystrophy.</a> Muscle and Nerve. 54 (2), 249-257 (2016).</li><li>Tan, S. V., 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=Membrane+dysfunction+in+Andersen-Tawil+syndrome+assessed+by+velocity+recovery+cycles.">Membrane dysfunction in Andersen-Tawil syndrome assessed by velocity recovery cycles.</a> Muscle and Nerve. 46 (2), 193-203 (2012).</li><li>Tan, S. V., 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=Chloride+channels+in+myotonia+congenita+assessed+by+velocity+recovery+cycles.">Chloride channels in myotonia congenita assessed by velocity recovery cycles.</a> Muscle and Nerve. 49 (6), 845-857 (2014).</li><li>Boland-Freitas, R., 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=Sarcolemmal+excitability+in+the+myotonic+dystrophies.">Sarcolemmal excitability in the myotonic dystrophies.</a> Muscle and Nerve. 57 (4), 595-602 (2018).</li><li>Stalberg, E., 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=Standards+for+quantification+of+EMG+and+neurography.">Standards for quantification of EMG and neurography.</a> Clinical Neurophysiology. 130 (9), 1688-1729 (2019).</li><li>Witt, A., 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=Muscle+velocity+recovery+cycles+in+neurogenic+muscles.">Muscle velocity recovery cycles in neurogenic muscles.</a> Clinical Neurophysiology. 130 (9), 1520-1527 (2019).</li><li>Kristensen, R. S., 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=MScanFit+motor+unit+number+estimation+(MScan)+and+muscle+velocity+recovery+cycle+recordings+in+amyotrophic+lateral+sclerosis+patients.">MScanFit motor unit number estimation (MScan) and muscle velocity recovery cycle recordings in amyotrophic lateral sclerosis patients.</a> Clinical Neurophysiology. 130 (8), 1280-1288 (2019).</li><li>Marrero, H. G., 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=Optimizing+testing+methods+and+collection+of+reference+data+for+differentiating+critical+illness+polyneuropathy+from+critical+illness+MYOPATHIES.">Optimizing testing methods and collection of reference data for differentiating critical illness polyneuropathy from critical illness MYOPATHIES.</a> Muscle and Nerve. 53 (4), 555-563 (2016).</li><li>Allen, D. C., Arunachalam, R., Mills, K. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Critical+illness+myopathy:+further+evidence+from+muscle-fiber+excitability+studies+of+an+acquired+channelopathy.">Critical illness myopathy: further evidence from muscle-fiber excitability studies of an acquired channelopathy.</a> Muscle and Nerve. 37 (1), 14-22 (2008).</li></ol>

MVRCs, as programmed in the recording software, is a highly automated procedure, but care is needed to obtain reliable results. In the recording stage, while adjusting the needles, it is important to avoid stimulating the end-plate zone or nerve. This usually leads to large twitches of the whole muscle, which increases the risk of displacement of the stimulation and/or recording needle during recording MVRCs. To date, the method has been applied to several muscles that have better described end-plate zone; however, the e...

Nerve conduction studies (NCS) and electromyography (EMG) are the conventional electrophysiological methods used for the diagnosis of neuromuscular disorders. NCS enables detection of axonal loss and demyelination in the nerves1, while EMG can differentiate whether myopathy or neurogenic changes are present in the muscle due to nerve damage. However, NCS or EMG provide limited information about muscle fiber membrane properties and underlying disease mechanisms. This information can be achieved using intracellular electrodes in isolated muscles from muscle biopsies2,3,4. However, it is of clinical importance to use methodologies using recordings from intact muscles in patients.
The velocity of a second muscle fiber action potential changes as a function of the delay after the first5, and this velocity recovery function (or recovery cycle) has been shown to change in dystrophic or denervated muscles. The yield of such recordings from single muscle fibers was, however, too low to be of use as a clinical tool6. However, Z&#39;Graggen and Bostock later found that multi-fiber recordings, obtained by direct stimulation and recording from the same bundle of muscle fibers, provide a fast and simple method of obtaining such recordings in vivo7. A sequence of paired pulse electrical stimuli with varying interstimulus intervals (ISIs) is used in this method7,8,9,10,11.
The evaluated MVRC parameters include the following: 1) muscle relative refractory period (MRRP), which is the duration after a muscle action potential until the next action potential can be elicited; 2) early supernormality (ESN); and 3) late supernormality (LSN). ESN and LSN are the periods after the refractory period in which the action potentials are conducted along the muscle membrane faster than normal. The depolarizing afterpotential, and potassium accumulation in the t-tubules of the muscle respectively, are hypothesized as the main causes for the two periods of supernormality.
The wide applicability of MVRCs to muscle disorders has been shown in detecting membrane depolarization in ischemia7,10,12 and renal failure13, as well as providing information about muscle membrane abnormalities in critical illness myopathy14 and inclusion body myositis15. Frequency ramp and intermittent 15 Hz and 20 Hz simulation protocols have since been introduced. MVRCs, together with these additional protocols, have demonstrated the different effects on muscle membrane excitability related to loss-of-function or gain-of-function mutations in various muscle ion channels in the inherited muscle ion channelopathies (i.e., sodium channel myotonia, paramyotonia congenita16, myotonic dystrophy17, Andersen-Tawil syndrome18, and myotonia congenita19,20).
In a recent study, the applicability of MVRCs to neurogenic muscles was shown for the first time. The term &#34;neurogenic muscle&#34; refers to the secondary changes in skeletal muscles that develop as denervation and reinnervation after any injury to the anterior horn cells or motor axons. Denervation is characterized in EMG as spontaneous activity (i.e., fibrillations [fibs] and positive sharp waves [psws]), while large motor unit potentials with prolonged duration and increased amplitude present reinnervation21. EMG changes are evident in denervated muscles, but the underlying cellular changes in muscle fiber membrane potentials have only been demonstrated in experimental studies on isolated muscle tissue2,3,4. MVRCs provide further insight into in vivo human muscle membrane properties regarding the denervation process.
This paper describes the methodology of MVRCs in detail. It also summarizes the changes in neurogenic muscles in a subgroup of patients from a previously reported study22 and healthy control subjects that enables determination of whether the method is appropriate for a planned study.
The recordings are performing using a recording protocol that is part of a software program. Other equipment used is an isolated linear bipolar constant current stimulator, 50 Hz noise eliminator, isolated electromyography amplifier, and analogue-to-digital converter.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>50 Hz Noise Eliminator</td>
			<td>Digitimer Ltd</td>
			<td></td>
			<td>Humbug</td>
		</tr>
		<tr>
			<td>Analogue-to-Digital Converter</td>
			<td>National Instruments</td>
			<td></td>
			<td>NI-6221</td>
		</tr>
		<tr>
			<td>Analysing software program</td>
			<td>Digitimer Ltd (copyright Institute of Neurology, University College, London)</td>
			<td></td>
			<td>QtracP, MANAL9</td>
		</tr>
		<tr>
			<td>Disposable concentric needle electrode, 25 mm x 30G</td>
			<td>Natus</td>
			<td></td>
			<td>Dantec DCN</td>
		</tr>
		<tr>
			<td>Disposable monopolar needle electrode, 25 mm x 26G</td>
			<td>Natus</td>
			<td></td>
			<td>TECA elite</td>
		</tr>
		<tr>
			<td>Isolated EMG amplifier</td>
			<td>Digitimer Ltd</td>
			<td></td>
			<td>D440</td>
		</tr>
		<tr>
			<td>Isolated linear bipolar constant-current stimulator</td>
			<td>Digitimer Ltd</td>
			<td></td>
			<td>DS5</td>
		</tr>
		<tr>
			<td>Software and recording protocol</td>
			<td>Digitimer Ltd (copyright Institute of Neurology, University College, London)</td>
			<td></td>
			<td>QtracW software, M3REC3 recording protocol written by Hugh Bostock, Istitute of Neurology, London, UK)</td>
		</tr>
	</tbody>
</table>

muscle velocity recovery cycles to examine muscle membrane properties

Although conventional nerve conduction studies (NCS) and electromyography (EMG) are suitable for the diagnosis of neuromuscular disorders, they provide limited information about muscle fiber membrane properties and underlying disease mechanisms. Muscle velocity recovery cycles (MVRCs) illustrate how the velocity of a muscle action potential depends on the time after a preceding action potential. MVRCs are closely related to changes in membrane potential that follow an action potential, thereby providing information about muscle fiber membrane properties. MVRCs may be recorded quickly and easily by direct stimulation and recording from multi-fiber bundles in vivo. MVRCs have been helpful in understanding disease mechanisms in several neuromuscular disorders. Studies in patients with channelopathies have demonstrated the different effects of specific ion channel mutations on muscle excitability. MVRCs have been previously tested in patients with neurogenic muscles. In this prior study, muscle relative refraction period (MRRP) was prolonged, and early supernormality (ESN) and late supernormality (LSN) were reduced in patients compared to healthy controls. Thereby, MVRCs can provide in vivo evidence of membrane depolarization in intact human muscle fibers that underlie their reduced excitability. The protocol presented here describes how to record MVRCs and analyze the recordings. MVRCs can serve as a fast, simple, and useful method for revealing disease mechanisms across a broad range of neuromuscular disorders.

The following results were obtained in a subgroup of patients from a recent study22, in which there were fibs/psws in all sites showing profuse denervation activity. The results showed that changes in muscle fibers after denervation were assessed in vivo using the MVRC technique described in this protocol. MVRCs showed changes consistent with depolarization of the resting membrane potential in the neurogenic muscle fibers.
Fourteen patients were compared with 29 healthy...

Watch this Scientific Journal Video about Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties at JoVE.com

Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties

Presented here is a protocol for the recording of muscle velocity recovery cycles (MVRCs), a new method of examining muscle membrane properties. MVRCs enable in vivo assessment of muscle membrane potential and alterations in muscle ion channel function in relation to pathology, and it enables the demonstration of muscle depolarization in neurogenic muscles.

Although conventional nerve conduction studies (NCS) and electromyography (EMG) are suitable for the diagnosis of neuromuscular disorders, they provide ...

This protocol describes how we examine muscle membrane changes in denervated muscles using MVRC, muscle velocity recovery cycles. The main advantage of MVRCs is that it's a fast and simple method for examining muscle membrane properties in vivo without discomfort for the subject. MVRCs may have a potential to be a diagnostic tool in neuromuscular disorders in the future.However, further studies are necessary to explore this possibility. We expect MRVCs to a valuable resource tool for understanding the pathophysiology behind several neuromuscular disorders and a biomarker for monitoring the disease progress and drug effects. Since there are no risks and only slight discomfort from this examination, we recommend that you practice on healthy subjects before examining patients.This technique is completely harmless as long as you follow basic instructions. So, remember to clean with alcohol before needle insertion and ensure that there are no contraindications such as hemophilia or blood thinning treatment. To begin, assess the subject's medical histories to ensure that they do not have any previous nervous system disorders other than the disease group that will be investigated.Inform the subject in detail about the examinations and request to obtain written consent. Inform the subject about the insertion of two needles in a leg muscle and that the muscle fibers will be stimulated with a weak current. Explain that the sensation may feel slightly unpleasant.Inform the subject that the stimulation can be turned off immediately at any moment during the recording in case of any discomfort. Then, clean the subject's lower leg with alcohol. Insert the stimulating monopolar needle electrode over the anterior tibial muscle.Insert the recording concentric needle electrode about two centimeters proximal to the stimulating monopolar needle electrode along the muscle fibers and put adhesive surface electrode as the anode one centimeter distal to the monopolar needle. Place a ground electrode distal to the anode. Connect the recording concentric needle and ground electrodes to the preamplifier.Ask the subject to remain silent and avoid movement during the examination. Zero the output of the stimulator and connect the stimulating electrodes to the stimulator. Maintain the skin temperature between 32 and 36 degrees celsius using a warming lamp.Start the stimulator and turn on the semi-automated recording software using the muscle excitability recording protocol. Stimulations start at 2.5 milliamps with one hertz. Increase the stimulus intensity manually by hitting the insert key until a response is recorded.If the potential appears upside down, hit the minus key to invert the muscle action potential. Adjust the stimulating and recording needles if necessary until recording an acceptable response with a stimulus intensity of less than 10 milliamps. The shape of the muscle action potential should be triphasic and stable.Avoid large twitches of the whole muscle. Muscle twitches of the whole muscle implies that you are stimulating the end plate. In this case, adjust the monopolar needle or reinsert both needle electrodes in a new site.A magenta horizontal line appears on the screen indicating the width of the action potential. Adjust the position and length of the magenta line by dragging the line with the mouse. The green horizontal line represents the baseline.Select stimulus response relationship from the main options. Increase stimulus intensity by hitting the insert key to a max of 10 milliamps or tolerable. Click OK to start descending the stimulus response curve.Click OK when the test stimulus reaches zero. Set the stimulus intensity to level for stable latency. Click OK to return to the main menu.Select the option 1-2-5 conditioning stims for recovery cycles. Select a protocol from the recovery cycle options. For example, start quick recovery cycle, skip alternate delays.Make sure the muscle action potential is stable during the recording and that the needle has not moved. The screen changes automatically to main options when the 34 steps have completed. Click on finish recording and click the save data button.Start the analyzing software program to perform the analysis offline. Select the recording that will analyzed and click on the OK button. Click on load parameters from the files menu.Select the MANAL9 option for the analysis. Click OK to continue. When a description of the MANAL9 muscle excitability analysis appears, click OK to continue.If the potential appears upside down, invert the muscle action potential by typing MM-1. Right click the mouse to make the magenta line visible. Set the window to the base of the peak response and with a width corresponding roughly to the width of the action potential at that height.Track with the mouse to adjust the window. The window determines the latencies within which the height and latency are measured as indicated by the pale blue lines, and the green line indicate the baseline. Click OK to continue.Click OK to remeasure the latencies and peaks. Click OK to create an RMC file. Ignore most of the options appearing in the create RCC or RMC form.Click save and exit to continue. After saving the RMC file, the prompt box provides different options. If frequency ramp and/or repetitive stimulation data have been recorded, follow the instructions to analyze these.Otherwise, select go straight to create MEM file option to create a MEM file. Click OK to continue. Click save and exit to continue.Click OK to add the RMC data to the MEM file. Click add from input RMC file to add this data to the MEM file, then change the directory to save the composite MEM file. Then, click save and exit to save it.Click OK to save the remeasured QZD file to allow differentiation from the original QZD file using a pound sign. In this study, 14 patients were compared to 29 healthy subjects. Subject demographics are shown here.Recordings from a healthy subject and a patient show distinct difference in percentage change in latency. Comparison of patients'MRVCs with healthy subjects'shows that MRRP was prolonged and early supernormality and late supernormality were reduced in patients compared to healthy controls. The most important step in the MVRC recording is correct needle positioning, where you get a stable amplitude with a stimulus intensity less than 10 milliamps.

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