Department of Psychology, University of Osnabrueck, Osnabrueck, Germany.
Phytomedicine. 2011 Nov 15;18(14):1202-7. doi: 10.1016/j.phymed.2011.06.021. Epub 2011 Jul 30.
Recent reviews showed that Ginkgo biloba extract EGb 761(1) is effective to enhance performance in patients with cognitive impairment (e.g., dementia). The aim of this study was to investigate the effects of EGb 761 on memory and the specificity of such effects on distinct memory functions in middle-aged healthy volunteers.
A total of 188 healthy subjects aged 45-56 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-placebo 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-placebo 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-placebo 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.
最近的综述表明，银杏叶提取物 EGb 761（1）可有效改善认知障碍患者（如痴呆）的认知表现。本研究旨在调查 EGb 761 对记忆的影响，以及其对中年健康志愿者不同记忆功能的特异性影响。
共 188 名年龄在 45-56 岁的健康受试者随机接受 EGb 761（每日一次 240mg）或安慰剂治疗 6 周。主要结局指标为在一项要求较高的标准化自由回忆范式（约会清单）和一项要求较低的标准化识别测试（驾驶路线）中记忆表现的变化。基于先前的研究结果，我们预测 EGb 761 在回忆测试中具有优越性。通过分离即时与延迟、数量与质量的自由回忆测量来评估效应的特异性。
6 周后，EGb 761 治疗组在回忆数量上显著改善，即正确回忆的约会次数（即时回忆的药物-安慰剂差异：p=0.038；延迟回忆的药物-安慰剂差异：p=0.008）。对定性回忆表现（错误与正确项目的比值）的影响相似（即时回忆的药物-安慰剂差异：p=0.092；延迟回忆的药物-安慰剂差异：p=0.010）。在另一个要求回忆驾驶路线的日常记忆测试中，银杏叶并未显示出优越性（药物-安慰剂差异：p>0.10）。不良事件的发生率低，且两组间无显著差异。
EGb 761（每日一次 240mg）可改善中年健康志愿者对约会的自由回忆，这需要对所学材料进行高要求的自我检索。该功能易受正常衰老的影响，即健康中年受试者的记忆功能下降。在一项要求较低的日常记忆任务中，没有观察到这种影响，因为该任务没有涉及到这一关键功能。这与先前的研究结果一致，即 EGb 761 在高要求的认知任务中具有特异性获益模式。
