A method for standardization of silent period measurements in human masseter muscle

The effect of bite force and stimulus intensity on the electrically induced SP has been studied. The results from the present study and earlier investigations suggest that the following guidelines should be used in future SP studies. (i) The electrical rather than mechanical way of stimulation should be preferred since the stimulus parameters and the receptors stimulated can easily be determined. (ii) The sensory perception threshold (T) of subjects should be used when studying and comparing the SP between individuals rather than the actual values of the electrical stimulation since the value of the sensory perception threshold varies from subject to subject. (iii) Rectified and averaged EMG records should be used rather than single raw traces since it is not possible to measure the duration of SPs from single traces. (iv) The subject should be asked to perform 25% of his/her MBF and the BF should be given as a feedback. (v) A stimulus intensity of about 6T should be used so that small changes in the BF would not affect the SPD. (vi) A jaw separation of about 10 mm should be selected in the subjects with normal overjet (2-3 mm), this being slightly thicker than the average isometric force transducer. The transducer can be brought to this thickness using acrylic resin. (vii) A head rest should be used to keep the head position constant (and hence constant jaw position with respect to the transducer) since the head position alone may change the reflexes elicited in the jaws region.