Kennedy D O, Scholey A B, Wesnes K A
Division of Psychology, University of Northumbria, Newcastle upon Tyne, UK.
Psychopharmacology (Berl). 2000 Sep;151(4):416-23. doi: 10.1007/s002130000501.
Chronic administration of extracts from the leaves of the tree Ginkgo biloba is known to improve aspects of cognitive performance. However, little is known about the effects of acute doses of Ginkgo on coherent cognitive domains. Recent factor analysis of test measures from subtasks of the Cognitive Drug Research (CDR) computerised assessment battery has revealed that four primary cognitive 'factors' corresponding to speed of attention, accuracy of attention, speed of memory and quality of memory can be useful to describe cognitive function changes.
The present study aimed at assessing whether acute administration of Ginkgo biloba had any consistent effect on the four CDR factors.
The study utilised a placebo-controlled, multi-dose, double-blind, balanced, crossover design. Twenty participants received 120 mg, 240 mg and 360 mg of a standardised extract of Ginkgo (GK501, Pharmaton, SA) or a matching placebo. Cognitive performance was assessed using the CDR computerised test battery immediately prior to dosing and at 1, 2.5, 4 and 6 h thereafter. The primary outcome measures were the four aspects of cognitive performance, which have previously been derived by factor analysis of CDR subtests.
Compared with the placebo, administration of Ginkgo produced a number of significant changes on the performance measures. The most striking of these was a dose-dependent improvement of the 'speed of attention' factor following both 240 mg and 360 mg of the extract, which was evident at 2.5 h and was still present at 6 h. Additionally, there were a number of time- and dose-specific changes (both positive and negative) in performance of the other factors.
We conclude that acute administration of Ginkgo biloba is capable of producing a sustained improvement in attention in healthy young volunteers.
已知长期服用银杏叶提取物可改善认知能力的某些方面。然而，关于银杏叶急性剂量对连贯认知领域的影响却知之甚少。最近对认知药物研究（CDR）计算机化评估电池子任务测试指标的因素分析表明，对应注意力速度、注意力准确性、记忆速度和记忆质量的四个主要认知“因素”有助于描述认知功能变化。
本研究旨在评估银杏叶急性给药是否对四个CDR因素有任何一致的影响。
本研究采用安慰剂对照、多剂量、双盲、平衡、交叉设计。20名参与者分别接受120毫克、240毫克和360毫克的银杏叶标准化提取物（GK501，Pharmaton，SA）或匹配的安慰剂。在给药前及给药后1、2.5、4和6小时使用CDR计算机化测试电池评估认知表现。主要结局指标是认知表现的四个方面，这些方面先前已通过CDR子测试的因素分析得出。
与安慰剂相比，银杏叶给药后在表现指标上产生了一些显著变化。其中最显著的是服用240毫克和360毫克提取物后“注意力速度”因素呈剂量依赖性改善，在2.5小时时明显，6小时时仍然存在。此外，其他因素的表现还存在一些时间和剂量特异性变化（包括正向和负向）。
我们得出结论，银杏叶急性给药能够使健康年轻志愿者的注意力得到持续改善。
