Improved automatized recording of masticatory reflexes through analysis of effort trajectory during biofeedback

Tap and sound evoked inhibitory motor reflexes within masseteric EMG were studied by means of a new technique that uses real time analysis of the trajectory followed during voluntary occlusal effort, controlled through visual biofeedback, in order to stimulate on exactly the same activity background. This technique uses a two computers system, doing parallel processing to support data acquisition, video indication, calculus of the pursued trajectory and evaluation of it. Stimuli were automatically delivered when the effort's trajectory fulfilled a set of conditions. Denomination of reflexigram (RFXG) is proposed to the cumulative, rectified and filtered EMG's series so recorded. Normal morphologies of RFXG were established on a 90 normal patients group. Clear clinical correlations were also found within two groups: 30 bruxists and 50 with temporomandibular joint dysfunction.