The investigators want to study the effect of intravenous anesthesia on postoperative cognitive function in patients accepted gastroenteroscopy ,no additional medication or operation is involved.The investigators assess cognitive function through a series of tests for 4 times( within 3 days before the endoscopy ,2 hours after the endoscopy finished,1 week after the endoscopy,3 months after the endoscopy),including WCST、DSST、DST、HADS、MoCA,through self - contrast,the investigators will conclude whether intravenous anesthesia has bad impact on cognitive function or not .
The investigators want to study the effect of intravenous anesthesia on postoperative cognitive function in patients accepted gastroenteroscopy ,no additional medication or operation is involved