Patients with traumatic brain injury are often referred to by physicians as vegetative, or what is often referred to clinically as a persistent vegetative state, which is caused by extensive damage to forebrain structures, especially the neocortex, from a variety of causes. The basic manifestation is an open-eyed coma and the presence of sleep-wake cycles. Basic vital functions persist, but there is no conscious mental activity, and there is urinary and fecal incontinence. Our current diagnostic criteria for the vegetative state are seven: 1) loss of cognitive function, no conscious activity, and inability to carry out instructions; 2) maintenance of voluntary respiration and blood pressure; 3) presence of sleep-wake cycles; 4) inability to understand or express language; 5) ability to open the eyes automatically or under stimulation; 6) purposeless eye tracking movements; 7) basic preservation of subthalamic and brainstem functions. When the above symptoms persist for more than 1 month, it is considered as persistent vegetative state.