Many people have many abnormal physical problems as they enter old age, the most common of which is the mirror sign. Mirror signs occur when the nervous system begins to decline, and people with mirror signs are not in control of their behavior and thoughts. There are many reasons for the appearance of the mirror sign, and what are the precursors of the mirror sign, let’s learn more about it. There are some precursory symptoms of mirror sign, and this disease has a great impact on the life of patients, so patients need to clearly understand the precursory symptoms of mirror sign. The precursor symptoms of mirror sign are: memory loss, patients can’t remember some things in the short term, people with severe disease will have no memory of things that just happened, abnormal language expression, forgetting how to express certain words correctly, loss of time concept and sense of direction, patients will often appear lost, and there is no a correct concept of day and night, judgment and alertness is reduced, to the Patients with the mirror sign do not have a correct perception of day and night, have reduced judgment and alertness, have no ability to judge some external injuries, and are not at all alert. Their personalities may change, and patients with the mirror sign are not able to correctly express happiness and sadness like normal people. In addition to the precursory symptoms of the mirror sign, there are five symptoms that one must be alert to. There are five kinds of symptoms that need to be watched out for: poor thinking and monotonous speech, the patient will often talk to himself, and will say a thing countless times, and the patient does not feel these practices; visual-spatial function is damaged, and can not find the way home, so the patient will have the phenomenon of getting lost, and the things they put in a place, after a period of time will also forget; memory loss, will slowly forget There is no memory of the past; personality and emotion change, temperament may be good and bad, and suspicious of the outside world; calculation ability is reduced, a little bit of complex number calculation, there will be slow or can not calculate the phenomenon. The substance and other substances poisoning: alcoholism, chronic sprinkler poisoning people caused by dementia is not uncommon, in is not yet recognized. Long-term exposure to aluminum, mercury, gold, silver, arsenic and lead can lead to dementia after chronic poisoning caused by poor protection. Carbon monoxide poisoning is also a common cause of acute dementia. Nutritional and metabolic disorders cause damage to brain tissue and its functions, leading to dementia. For example, various organ-induced encephalopathies, such as renal encephalopathy, which is chronic renal failure and uremia causing ischemia and hypoxia in the brain, can lead to dementia; others, such as hepatic encephalopathy and pulmonary encephalopathy, can lead to dementia.