< positive >1 case data the patient, a 57 year old female, presented with limb weakness two years ago and fell while walking on the flat road, and then fell more and more frequently; Half a year before admission, he began to react slowly, and his personality gradually developed from cheerful to less talkative with a giggle. One month before admission, in addition to falling and giggling, he also had unstable sitting and standing, occasionally choking and coughing with drinking water, and there was no headache, dizziness, limb twitching and visual impairment during the course of the disease. Denied the history of hypertension and diabetes in the past; Deny the history of cerebrovascular disease, genetic history and mental disease; Denied the history of surgery and trauma. Physical examination: vital signs were stable.