Abstract: An amplifier is brought in contact with the muscles of a subject for detecting and amplifying a muscle current, an envelope forming means forms an envelope waveform of the output of the amplifier, and, a time is measured for which the level of the envelope waveform exceeds at least one preset reference level. The shape or position of the display is changed in an image plane depending on the measurement result, or the reference values and the measurement results of the muscle activity are displayed side by side. Strength and/or duration of occlusion by the masticatory muscles of the jaws, and the imbalance in the activity of the pair of left and right muscles can easily be measured and analyzed on the basis of the counting result, but also the analytical result can be used to set the reference values for measuring the envelope waveform level that is optimum for a particular patient.

Abstract: A measurement device which can easily measure and analyze the activity of the muscles of the living organism, for instance, measure the strength of occlusion of the masticatory muscles and duration thereof. The vital muscle activity measurement device comprises an amplifier means brought in contact with the muscles of a subject for detecting and amplifying a muscle current, an envelope forming means for forming an envelope waveform of the output of the amplifier means, and a timer means for determining the time for which the level of the envelope waveform obtained by the envelope forming means exceeds a preset reference level.