Abstract Details

Title Refining Compound Muscle Action Potential as a Translational Biomarker of Neuromuscular Integrity

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) P5 - Poster Session 5 (11:45 AM-12:45 PM)

Poster/Presentation
Number 11-003

Objective

To investigate the impact of electrode type and high pass filter settings on compound muscle action potential (CMAP) recordings in mouse models with the goal to optimize preclinical approaches.

Background CMAP is a routine biomarker in both clinical and preclinical studies to quantify neuromuscular integrity in the context of neuromuscular disease, injury, or aging. A wide range of technical approaches have been used, and optimization is needed.

Design/Methods 16 C57Bl/6 mice (50% female) underwent right sciatic nerve crush or sham surgery. Nine CMAPs per mouse were recorded from the gastrocnemius (blinded to groups) two weeks after injury or sham (disc, needle, and ring electrodes with high pass filtering at 10, 150, 500 Hz). Twitch and tetanic plantarflexion contractility torque and triceps surae muscle weight were recorded. Pearson correlation coefficients were calculated.

Results CMAP amplitudes were significantly reduced with disc (p<0.001), needle (p<0.0001), and ring (p<0.0001) electrodes across filter settings in injured mice (unpaired t-tests). Twitch significantly correlated with disc (10 Hz: 0.8066, 150 Hz: 0.8041, 500 Hz 0.79300; p<0.05) and ring (10 Hz: 0.8153, 150 Hz: 0.8538, 500 Hz: 0.8941; p<0.05) but not needle. Similarly, tetanic correlated with disc (10 Hz: 0.7384, 150 Hz: 0.7286, 500 Hz: 0.7352; p<0.05) and ring (10 Hz: 0.7813, 150 Hz: 0.8216, 500 Hz: 0.8378; p<0.05) but not needle. Muscle weight correlated with needle (10 Hz: 0.9349, 150 Hz: 0.8778, 500 Hz: 0.8614; p<0.01) and ring (10 Hz: 0.7687, 150 Hz: 0.7475; p<0.05) but not disc.

Conclusions All CMAP approaches detected injury status. Electrode type had the greatest impact on correlation with muscle size and function. In contrast, while filter settings impact CMAP amplitude, filter settings did not overtly impact detection of injury status or physiological correlations. Overall, our results support the use of ring electrodes which offer additional benefits of being non-invasive with standard filter settings.

Authors/Disclosures
Sindhuja Ayyagari PRESENTER	Ms. Ayyagari has nothing to disclose.
	No disclosure on file
William D. Arnold, MD	Dr. Arnold has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Arnold has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for La Hoffmann Roche. Dr. Arnold has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Cadent Therapeutics . Dr. Arnold has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Novartis. The institution of Dr. Arnold has received research support from NIH. The institution of Dr. Arnold has received research support from NMD Pharma. The institution of Dr. Arnold has received research support from Gilead Sciences. The institution of Dr. Arnold has received research support from CureSMA. Dr. Arnold has received intellectual property interests from a discovery or technology relating to health care.

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