The Reliability of the Bilateral Trigeminal Roots-motor Evoked Potentials as an Organic Normalization Factor: Symmetry or Not Symmetry?

Background: In order to achieve a complete clinical evaluation of mastication, an in-depth neurophysiopathological assessment of masticatory muscles control is needed. Electromyography technique (EMG) is widely used for this purpose but failed to give convincing results. The aim of this work was to describe our quantitative objectivation of the motor control of the masticatory muscles and to verify the hypothesis to consider the bilateral Root Motor Evoked Potentials as an electrophysiological normalization factor. Methods: 25 healthy people (15 males, 10 females; mean age 29 years ± 5) with normal occlusion and no history of temporomandibular disorders and orofacial pain underwent a transcranical electrical stimulation that allowed a direct bilateral stimulation of the motor roots of the trigeminal motor system called bilateral Root Motor Evoked Potentials (bRMEPs). The maximal Absolute Neural Evoked Energy, symmetry and synchrony properties of the resulting b R-MEPs were studied using measures like latency, amplitude and integrated area of the collected signal. An Artificial Neural Network computational model was used to estimate the correlation coefficient with the EMG values of each of both sides to predict the values from the right side by inputting values from the left side.