Severe cerebral blood supply insufficiency will appear the following symptoms: First, there will be abnormal mental consciousness, insufficient blood supply to the brain will cause cerebral ischemia, hypoxia, thus impairing the normal physiological function of the brain, severe cerebral blood supply insufficiency is likely to cause cerebral blood vessels rapid ischemia, hypoxia, contraction, spasm, thus resulting in stupor, call out, pupil light reflex disappears, and other symptoms. Secondly, it will damage the cerebral nerves to different degrees, thus causing motor nerve dysfunction and sensory dysfunction, which often manifests as drowsiness, weakness, fatigue, mental lethargy and other symptoms throughout the day. Thirdly, insomnia, indifference, memory loss, and even loss of correct judgment will also occur. Fourth, there are spasms and throbbing of the limbs, as well as numbness of the face, hands and feet, numbness of the lips and mouth, numbness of one side of the limbs, and the symptom of blurred vision can also occur.