The herbal supplement ginkgo biloba did not improve cognitive function in people with MS in a recent research study involving 120 people at the LSU Health Sciences Center in New Orleans. This study followed up on a promising earlier small study by Dr. Jesus Lovera, assistant professor of neurology, and his colleagues that had shown improvement in cognitive function with ginkgo biloba in people with MS. Some studies have also shown improvement after treatment with ginkgo biloba in people with Alzheimer's disease.
"Ginkgo biloba supplements are frequently used by people with MS. Ginkgo appeared beneficial in a prior small pilot study we had done," says Dr. Lovera.
The researchers wanted to conduct a larger, more robust study to determine the validity of the preliminary results. One hundred twenty people with MS were randomized to either the group treated with 120 mg of ginkgo biloba twice a day, or to the group taking matching placebo tablets. Participants were treated for 12 weeks and then underwent a battery of cognitive tests. Participants and their families also answered standardized questionnaires about their cognitive function and social integration. The tests found that there were no statistically significant improvements in cognitive function between the two groups.
"Unfortunately we did not see any improvement with ginkgo in this new study," notes Dr. Lovera. "Several drugs such as Namenda and Aricept that work for people with Alzheimer's have been tested without success in people with MS. Unfortunately now ginkgo is added to the list of therapies thought to be effective in Alzheimer's disease that failed to improve cognitive performance in MS."
While the study provides solid evidence, the researchers noted several limitations. Participants were treated for only 12 weeks and perhaps that was not long enough to modify the disease. The median duration of MS was 20 years, and it is possible that ginkgo may improve cognitive function earlier in the MS disease process. It is also possible that there could have been a positive effect in participants with more severe impairments than those in this study. Additional functional assessments that measure performance in real-life situations may also have detected an effect that was missed by limiting the outcome measures to cognitive tests and questionnaires.
Cognitive impairment affects 40-60% of people with MS, most commonly affecting their processing speed, memory, and executive skills. The research findings were published online ahead of print in Neurology.