Evaluation of Motor Neuron Excitability by CMAP Scanning with Electric Modulated Current

Introduction. Compound Muscle Action Potential (CMAP) scan is a noninvasive promissory technique for neurodegenerative pathologies diagnosis. In this work new CMAP scan protocols were implemented to study the influence of electrical pulse waveform on peripheral nerve excitability. Methods. A total of 13 healthy subjects were tested. Stimulation was performed with an increasing intensities range from 4 to 30 mA. The procedure was repeated 4 times per subject, using a different single pulse stimulation waveform: monophasic square and triangular and quadratic and biphasic square. Results. Different waveforms elicit different intensity-response amplitude curves. The square pulse needs less current to generate the same response amplitude regarding the other waves and this effect is gradually decreasing for the triangular, quadratic, and biphasic pulse, respectively. Conclusion. The stimulation waveform has a direct influence on the stimulus-response slope and consequently on the motoneurons excitability. This can be a new prognostic parameter for neurodegenerative disorders.

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Studying the Liason between Motor Unit Number Estimate (MUNE) and the Total Slope of a Stimulus-Response (SR) Curve of Compound Muscle Action Potential (CMAP) Scan

10.1109/tiptekno53239.2021.9632945 ◽

2021 ◽

Author(s):

Imran Goker ◽

Mehmet Baris Baslo ◽

Ali Emre Oge

Keyword(s):

Action Potential ◽

Motor Unit ◽

Compound Muscle Action Potential ◽

Muscle Action ◽

Stimulus Response ◽

Muscle Action Potential ◽

Motor Unit Number Estimate

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Facial Motor Neuron Excitability in Hemifacial Spasm: A Facial MEP Study

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100016644 ◽

2014 ◽

Vol 41 (2) ◽

pp. 239-245 ◽

Cited By ~ 8

Author(s):

Marshall F. Wilkinson ◽

Anthony M. Kaufmann

Keyword(s):

Motor Neuron ◽

Skull Base ◽

Hemifacial Spasm ◽

Motor Evoked Potential ◽

Single Pulse ◽

Skull Base Tumor ◽

Tumor Patients ◽

Central Hypothesis ◽

Motor Neuron Excitability ◽

Pulse Stimulation

Introduction:Hemifacial spasm (HFS) may be due to peripheral axon ephapsis or central motor neuron hyperexcitability. Low facial motor evoked potential (MEP) thresholds or MEP responses to single pulse stimulation (normally multipulse stimulation is needed) may support the central hypothesis.Methods:We retrospectively compared response thresholds for facial MEPs in 65 patients undergoing surgical microvascular decompression (MVD) for HFS and 29 patients undergoing surgery for skull base tumors.Results:Single pulse stimulation elicited facial Mep in up to 87% of HFS patients whereas only 10% of tumor patients responded to single pulse stimulation. When comparing facial MEP thresholds using multi-pulse stimulus trains the voltage required in the HFS group were significantly lower then in skull base tumor patients (p < 0.001). the MEP latencies and amplitudes at threshold stimulation were similar between the two groups.Conclusions:these results suggest the facial corticobulbar pathway demonstrates enhanced excitability in HFS.

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