A Retrospective Study to Investigate the Additive Effectiveness of Chinese Herbal Medicine in Alzheimer's Disease

Inclusion Criteria: * Gradual and progressive change in cognitive functions for a period greater than 6 months; * Objective evidence of significantly impaired episodic memory together with at least one of other cognitive domains on testing; * Global cognitive decline measured by mini-mental state examination (MMSE) adjusted for education: ≤22 for illiteracy, ≤23 for primary school, ≤24 for middle school,≤26 for high education; * Impaired abilities of daily living, ADLs score ≥16; * Clinical Dementia Rating (CDR) total score 0.5\~3.0; * ≤4 point on Hachinski Ischaemic Score (HIS); * Age-adjusted medial temporal lobe atrophy scale (MTA-scale) based on coronary magnetic resonance imaging (MRI) scan of the brain (1.0 or more for ≤65 years; 1.5 or more for ≤75 years and 2.0 or more for ≥75 years); * Other causes of dementia excluded. Exclusion Criteria: * Sudden onset of cognitive disorder with focal nervous system signs in the early stages of disease, (e.g., incomplete paralysis, anesthesia, dysfunctional visual field, and dystaxia); * Early occurrence of the following symptoms: gait disturbances, seizures, extrapyramidal signs, hallucinations and cognitive fluctuations; * Any major psychiatric disorders (e.g., DSM-IV(Diagnostic and Statistical Manual of Mental Disorders) defined psychosis, major depression, bipolar disorder, or alcohol or substance abuse); * Other conditions that may explain cognitive impairment (e.g., hypothyroidism, electrolyte imbalance, toxic, inflammatory, and metabolic disorders).