Randomised double-blind placebo controlled trials (RCTs) that evaluated the effects of chronic administration (greater than four weeks) of Ginkgo biloba (at any concentration and over any period of time) on objective function-specific cognitive performance were eligible for inclusion. Studies of treatments of less than one month and those that reported global cognitive and pure sensory measures were excluded. All participants were considered irrespective of age and diagnosis (if any).
The included studies included participants with dementia, mild cognitive impairment (MCI), depression and multiple sclerosis. Healthy participants were included. Mean age of participants ranged from 21 to 83 years. Preparations, doses and treatment durations of Ginkgo were varied and included: EGb 761 (120mg to 240mg, four to 24 weeks), Lichtwer’s LI 1370 (120mg to 150mg, six to 12 weeks), ethanolic extract (1.14mg, 24 weeks), Blackmore’s extract (120mg, 30 days to 12 weeks), standardised Ginkoba extract (80mg to 184.5mg, six to 13 weeks) and Maze produtos (80mg, eight months). Most trials evaluated EGb 761 extract. Cognitive outcomes considered included: memory (short-term, long-term), attention (intensity, selectivity), executive functions (working memory, concept formation, planning, flexibility) and intelligence (crystallised, fluid).
The authors stated neither how the studies were selected for the review nor how many reviewers performed the study selection.