AAN 2011: No Benefit from Ginkgo on Multiple Sclerosis Cognitive Impairment

Ginkgo extract offers no benefit for multiple sclerosis (MS) patients with cognitive impairment, according to a study presented at the 63rd Annual Meeting of the American Academy of Neurology.

Twelve weeks of treatment led to no significant improvements in any of four standard neuropsychological tests. “Currently, there are no approved therapies to treat cognitive impairment in multiple sclerosis, despite the fact that it affects forty to fifty percent of people with MS,” said Jesus Lovera, MD, of Louisiana State University in New Orleans.

Ginkgo extract has been tested for its potential benefits in other dementing illnesses, with variable results. According to a survey of MS patients in the Northwest United States, 20% of MS patients take the supplement.

A small pilot trial in MS suggested ginkgo may have improved performance in one cognitive domain. Based on those results, Lovera began a larger trial, sized to provide 80% power to detect a clinically significant difference in one of the four neuropsychological tests used in the trial, “about twice the magnitude of change expected from placebo,” he said.

The study enrolled 121 MS patients who scored worse than one standard deviation below the mean in any of the four parts of the Standard Neuropsychological Battery, comprising the Stroop test, the Paced Auditory Serial Addition Test, the California Verbal Learning Test II, and the Controlled Oral Word Association Test. Together, these tests assess attention, working memory, verbal learning, phonemic fluency, attention, and executive function.

Enrolled patients were randomized to placebo or to 120 mg ginkgo biloba extract twice per day for 12 weeks. The extract was obtained from the same source used for most Alzheimer's disease trials, and was “a very high-quality product,” Lovera said.

“Disappointingly, we did not see any effects of treatment on any of the cognitive tests,” when comparing 12-week improvements between active treatment and placebo, he said. In fact, patients on placebo improved more than those taking Ginkgo, although not significantly.

Neither was there any benefit on any of several secondary measures of cognition, fatigue, or depression. There were no differences in adverse effects and no serious adverse effects attributable to Ginkgo.

“Ginkgo was not effective at improving cognitive functions over the short run,” Lovera said. “There is no evidence that it helps.”

The study was funded by the Department of Veterans Affairs Research and Rehabilitation