A total of 188 healthy subjects aged 45?6 years were randomised to receive EGb 761 (240 mg once daily) or placebo for 6 weeks. Outcome measures were the change in memory performance in a demanding standardised free recall paradigm (list of appointments) and a less demanding standardised recognition test (driving-route). Based on previous findings we predicted superiority of EGb 761 in recall testing. Specificity in effects was assessed by separating immediate vs. delayed and quantitative vs. qualitative free recall measures.
After 6 weeks, EGb 761-treated subjects improved significantly in quantity of recall, i.e., the number of correctly recalled appointments (drug¨Cplacebo differences: p = 0.038 for immediate and p = 0.008 for delayed recall). Effects on qualitative recall performance (ratio of false to correct items) were similar (drug¨Cplacebo differences: p = 0.092 for immediate and p = 0.010 for delayed recall). No superiority of Ginkgo was evident in another everyday memory test which asked for recognition of a driving route (drug¨Cplacebo differences: p > 0.10). The incidence of adverse events was low and not significantly different between treatment groups.
EGb 761 (240 mg once daily) improves free recall of appointments in middle-aged healthy volunteers, which requires high demands on self-initiated retrieval of learned material. This function is known to be sensitive to normal aging, i.e., reduced in healthy middle-aged subjects. No effects are seen in a less demanding everyday memory task which does not tap this critical function. This ties in with previous studies which found specific patterns of benefit from EGb 761 in demanding cognitive tasks.