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Disorder in chewing food is a major problem in patients with stroke, some of those who suffer from brain lesion, multiple sclerosis, and other diseases such as head and neck cancer. This kind of disorder causes significantly decreased food consumption and consequently malnutrition or dehydration and in severe cases leads to suffocation. It can also increase the rate of death during the first year after the stroke to 45%. Therefore, finding an appropriate and common pattern of cooperation of jaw muscles in the act of chewing can have a very important role in assisting the process of rehabilitation in these patients. In this article, to improve current rehabilitation techniques for patients with chewing problems, attempts have been made to investigate the physiology of human chewing and involved muscles in this process. Extracting synergy patterns of jaw muscles during chewing action was also carried out in this article using analysis of the main components of electromyogram signal and quantification of muscle activity. The results show that each individual applies the same motion during different times for chewing action. Moreover, cooperation and interaction of the involved muscles are maintained in this process during various times in which the share of masseter muscle is more than temporal one in this collaboration.