Hiện tượng này là nổi bật nhất trong những cá nhân đang căng thẳng trong EEG và tối đa trong từ thời gian hoặc frontopolar (trang web của hệ thống cơ trán). Myogenic tiềm năng bao gồm các hoạt động tần số cao, nhiều briefer hơn so với tiềm năng | Normal EEG FIGURE . Muscle artifact at T4 manifests as repetitive single myogenic potentials. Oz has continuous single electrode artifact and a bifrontal burst of muscle artifact is seen in second 3 to 4. Note the 6-Hz positive bursts in the 8th second. Filter settings are 1 to 70 Hz. EEG courtesy of Greg Fisher MD . A myogenic muscle artifact consists of brief potentials that may occur individually or become continuous obscuring underlying EEG. EMG activity created during a seizure during muscle contraction or during movements are due to increased muscle tone. This artifact is most prominent in individuals who are tense during the EEG and is maximal in the temporal or frontopolar derivations the site of frontalis musculature . Myogenic potentials are composed of high-frequency activity that is much briefer than the 20-msec potentials seen with epileptiform discharges. In addition an aftergoing slow wave is absent and having the individual relax their jaw muscles or capturing sleep will lead to waning or elimination of a myogenic artifact. 17 CHAPTER 1 FIGURE . A chewing artifact seen at regular 1- to 2-second intervals. Note the continuous myogenic artifact in the bitemporal regions. Regular bursts of myogenic potentials are seen during chewing. These high-voltage temporal predominant bursts are due to contraction of the muscles associated with mastication. Associated slow potentials during chewing reflect associated swallowing movements created by the tongue. The tongue like the eye acts as a dipole with the tip of the tongue being positive relative to the root. The chewing that is an effect created by the temporalis muscles is accompanied thereafter by the glossokinetic movements of the tongue. 18 Normal EEG FIGURE . Pseudogeneralized spike-and-wave during intermittent photic stimulation due to superimposition of a physiological artifact from eye flutter and frontally predominant muscle artifact. Superimposition of background frequencies can be .
