Efficacy, Safety and Response Predictors of Adjuvant Astragalus for Cognition in Orthostatic Hypotension

Inclusion Criteria: The inclusion criteria will be as follows:

1. Male or female aged ≥50 years and ≤85 years
2. A decrease in systolic blood pressure of 20 mm Hg or a decrease in diastolic bloodpressure of 10 mm Hg within 3 minutes after standing.
3. Memory loss for at least 6 months, with a progressive worsening trend
4. Patients with mild or moderate disease degree, that is, the total score of MMSE: 14points < total score of MMSE <24 points, 0.5≤CDR≤2 points, and the total score of HAMD (24-item version) ≤20 points
5. Brain magnetic resonance imaging shows the degree of hippocampal atrophy is greaterthan or equal to grade 1
6. The modified Hachinski Ischemia Scale (m-HIS) score was < 4 points
7. The criteria described by the diagnostic and statistical manual of mental disorder-Vfor the diagnosis of dementia comply with the National Institute on Aging -Alzheimer's Association "Very likely AD" (National Institute of Aging-Alzheimer'sAssociation, 2011).
8. There are no obvious positive signs in nervous system examination;
9. The subjects have the ability of reading, writing and communication, have a stablecaregiver, accompany to attend the visit.
10. The basic treatment of AD before enrollment remained unchanged, and if long-term usersneeded to use it steadily for more than 4 weeks before randomization,the dose was keptas stable as possible during the study. Such drugs include: cholinesterase inhibitorsand diamantine.

Exclusion Criteria: The exclusion criteria will be as follows:

1. MRI showed significant focal lesions, including one of the following: a. There weremore than 2 infarcts with a diameter greater than 2cm; b. Infarcts in key areas suchas the thalamus, hippocampus, entorhinal cortex, parorhinal cortex, angular gyrus,cortex, and other subcortical gray matter nuclei; c. White matter lesion Fazekas Scale ≥3
2. Patients who have taken other Chinese medicine preparations in the past three months
3. Allergy or contraindication of astragalus
4. There are other neurological diseases that can cause brain dysfunction or cognitiveimpairment; Mental and neurological retardation is present; Presence of malignanttumor
5. The modified Hachinski Ischemia Scale (m-HIS) score was ≥ 4 points.
6. Patients who refuse or have MRI or EEG contraindications (pacemakers, coronary andperipheral arterial stents, Metal implants, claustrophobia, or severe visual orhearing impairment), refusing to draw blood
7. Pregnant or lactating patients;
8. Patients who have participated in other clinical studies within the past 3 months