Clinical Efficacy of Ginkgo Biloba Extract in the Treatment of Alzheimer's Disease

Inclusion Criteria:

1. All patients were diagnosed with dementia caused by AD in 2011, the latest diagnosticcriteria for Alzheimer's disease (NIA-AA), according to the patient's clinical andcranial imaging findings

2. Improved Hachinski ischemic scale score <4

3. All patients underwent head CT and / or MRI examinations and laboratory tests to ruleout other causes of dementia

4. MMSE(High school≤24,Primary school≤20;illiteracy≤17)

5. CDR 1-2

6. The subjects and nurses signed informed consent, and the nursing staff were able totake responsibility for the supervision of the participants

7. The subjects were stable

8. Cooperate, willing to complete all parts of the research, and have the ability tocomplete the study alone or with the help of the nursing staff

9. To cooperate with the study, do not live alone, such as living alone should keep intouch with the nurse every day.

Exclusion Criteria:

1. Heart lung kidney disease, may interfere to evaluate the efficacy and safety ofpatients at risk or special disease,for example:Congestive heart failure et al.

2. According to NINDS-AIREN standard (Roman GC et al 1993) is currently diagnosed aspossible vascular dementia

3. Improved Hachinski ischemic scale score（MHIS）≥4

4. Diagnosis of severe depression, schizophrenia, and other major neurodegenerativedisorders, according to the DSM-IV axis

5. Neurological or other medical disorders that affect the function of the centralnervous system,like Moderate anemia,Vitamin B12 or folic acid deficiency, et al. Notwith the cognitive function examination (including blindness, deafness, severelanguage disorders).