Randomised controlled trials (RCTs) and quasi-RCTs that compared any form of a single herb or formulation with placebo, no intervention or other therapy and reported outcomes that related to memory, cognitive function, activities of daily living or quality of life were eligible for inclusion. Studies of Ginkgo biloba and plant-derived purified compounds as principal test interventions were excluded. To be included, participants had to have memory and/or other cognitive impairment associated with age and/or other age-related decline in physical or mental functioning consistent with MCI and/or AAM. Studies that included participants with Alzheimer's disease, vascular dementia or other dementia were excluded.
Interventions varied in the included studies and included Jia Wei Wu Zi Yan Zong Ke Li granules, Yi Nao Chong Ji granules, Jian Pi Tian Jing Fang capsules, Yin Zing Ye Jiao Nang capsules, Huan Nao Yi Chong Jiao Nang capsules, Deng Zan Hua Su dry powder for injection, Jin Si Wei Wan pills, Nao Li Bao Wan pills, Jia Jian Da Bu Yin Wan raw herbs in water decoction and Nao Li Bao Wan pills. Concentrations and composition of herbal medicine varied between studies.
Most studies compared Chinese herbal medicines with other interventions; the remaining two studies used a placebo control group. Treatment duration ranged from two to 10 months.
Outcomes were measured using a variety of instruments, including: Adult Memory and Information Processing Battery (AMIPB), Mini-Mental State Examination (MMSE), MMSE-R (revised in China), electrocardiograph (ECG), clinical memory scale (CMS), cognitive effect index (CEI), functional activities questionnaire (FAQ), cognitive capacity screening examination (CCSE), clinical dementia rating scale (CDR), global deterioration scale (GDS), Wechsler memory scale (WMS), Wechsler adult intelligence scale (WAIS), memory quotient (MQ), SF-36 Health Survey, Hachinski Ischemic Scale (HIS) and the Blessed dementia scale (BDS). Triglycerides, total cholesterol, high density lipoprotein (HDL-C), transcranial doppler (TC), superoxide dismutase (DOS), malondialdehyde (MDA) and acetylcholinesterase (AchE) were also measured.
The mean age of included participants ranged from 57 years to 72 years. Most participants in the included studies experienced mild cognitive impairment and others experienced age-related memory decline consistent with age associated memory impairment. All the included studies were conducted in China.
Two reviewers independently selected papers for inclusion.