Can ginkgo biloba extract improve cognitive function among multiple sclerosis patients?
Date of publication of the randomized controlled trial: September 2012
Design
Randomized controlled trial (RCT).
Participants
121 patients (mean age: 52.1 years, male %: 45%) with multiple sclerosis defined by McDonald’s criteria and scored ≥ 1 SD below on one of 4 neuropsychological tests (Stroop Test, California Verbal Learning Test II, Controlled Oral Word Association Test and Paced Auditory Serial Addition Task).
Intervention
Twice-daily dose of 120 mg Ginkgo biloba extract for 12 weeks.
Comparator
Comparison: Ginkgo biloba extract versus placebo.
Major Outcomes
Outcome 1: Neuropsychological score measured by Paced Auditory Serial Addition Task (PASAT). Higher scores indicated better cognitive function;
Outcome 2: Neuropsychological score measured by Stroop Test. Higher scores indicated better cognitive function;
Outcome 3: Neuropsychological score measured by Controlled Oral Word Association Test (COWAT). Higher scores indicated better cognitive function;
Outcome 4: Neuropsychological score measured by California Verbal Learning Test II (CVLT-II). Higher scores indicated better cognitive function.
Settings
This trial was performed in an outpatient setting.
Comparison    Ginkgo biloba extract versus placebo
Main Results
Compared to placebo, Ginkgo biloba extract do not have significant effect on improving cognitive function assessed by PASAT (mean difference (MD): -0.2, 95% CI: -0.5 to 0.1), Stroop test (MD: -0.5, 95% CI: -0.9 to -0.1), COWAT (MD: 0.0, 95% CI: -0.2 to 0.3) and CVLT-II (MD: 0.0, 95% CI: -0.3 to 0.3) among multiple sclerosis patients.
Comparison: Ginkgo biloba extract versus placebo among multiple sclerosis patients
Outcomes No. of studies (Total number of participants) Mean z score (SD)/ No. of participants Heterogeneity test ( I2) MD (95% CI) Overall quality of evidence*
Intervention Comparator
1 1 (121) -1.3 (0.9)/ 61 -1.0 (1.1)/ 59 Not applicable as there is only 1 study. -0.2 (-0.5 to 0.1) Low
2 1 (121) -0.8 (1.8)/ 61 -0.3 (1.1)/ 59 Not applicable as there is only 1 study. -0.5 (-0.9 to -0.1) Low
3 1 (121) -0.7 (1.0)/ 61 -0.8 (1.0)/ 59 Not applicable as there is only 1 study. 0.0 (-0.2 to 0.3) Low
4 1 (121) -0.4 (1.2)/ 61 -0.4 (1.2)/ 59 Not applicable as there is only 1 study. 0.0 (-0.3 to 0.3) Low
Keys: SD = standard deviation; MD = mean difference; CI= confidence interval.
Comparison    Ginkgo biloba extract versus placebo
Main Results
Compared to placebo, Ginkgo biloba extract do not have significant effect on improving cognitive function assessed by PASAT (mean difference (MD): -0.2, 95% CI: -0.5 to 0.1), Stroop test (MD: -0.5, 95% CI: -0.9 to -0.1), COWAT (MD: 0.0, 95% CI: -0.2 to 0.3) and CVLT-II (MD: 0.0, 95% CI: -0.3 to 0.3) among multiple sclerosis patients.
Comparison: Ginkgo biloba extract versus placebo among multiple sclerosis patients
Outcomes 1 2 3 4
No. of studies (Total number of participants) 1 (121) 1 (121) 1 (121) 1 (121)
Mean z score (SD)/ No. of participants Intervention -1.3 (0.9)/ 61 -0.8 (1.8)/ 61 -0.7 (1.0)/ 61 -0.4 (1.2)/ 61
Comparator -1.0 (1.1)/ 59 -0.3 (1.1)/ 59 -0.8 (1.0)/ 59 -0.4 (1.2)/ 59
MD (95% CI) -0.2 (-0.5 to 0.1) -0.5 (-0.9 to -0.1) 0.0 (-0.2 to 0.3) 0.0 (-0.3 to 0.3)
Overall quality of evidence* Low Low Low Low
Keys: SD = standard deviation; MD = mean difference; CI= confidence interval.
Conclusion
Benefits
Compared to placebo, Ginkgo biloba extract is not significantly more effective for improving cognitive function among multiple sclerosis patients. For Outcome 1-4, the overall quality of evidence is low. Further research is likely to have an important impact on our confidence in this estimate of effect.
Harms
2 serious adverse events of myocardial infarction and severe depression were reported. They were believed to be unrelated to Ginkgo biloba treatment.
Link to Original Article
https://www.ncbi.nlm.nih.gov/pubmed/22955125
The synopsis is based on the following article:
Lovera JF, Kim E, Heriza E, Fitzpatrick M, Hunziker J, Turner AP, et al.Ginkgo biloba does not improve cognitive function in MS: a randomized placebo-controlled trial. Neurology. 2012 Sep 18;79(12):1278-84.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.