An examination of the efficacy of Ginkgo biloba extract EGb 761 on the neuropsychologic functioning of cognitively intact older adults

Objectives: Few investigations have examined the effectiveness of Ginkgo bi loba extract for enhancing cognitive abilities in individuals with no histo ry of significant neurocognitive dysfunction. The purpose of this research was to examine the relatively short-term (i.e., 6 weeks) efficacy of Ginkgo biloba extract EGb 761 on the cognitive functioning of cognitively intact persons over the age of 55 years via a diverse battery of neuropsychologic tests and measures. Participants: From the 48 cognitively intact participants between the ages of 55 and 86 years who initially enrolled in this study, 21 males and 19 fe males successfully completed the study's protocol and provided valid data s ets. Design: A 6-week, double-blind, fixed-dose, placebo-controlled, parallel-gr oup experimental design was utilized. Participants were randomly assigned t o either a Ginkgo biloba extract EGb 761 (180 mg/d) or placebo control grou p. To evaluate participants' cognitive and behavioral functioning, series o f neuropsychological tests were administered to them prior to the initiatio n of the Ginkgo biloba extract/placebo therapy (i.e., pretreatment baseline ) and again, just prior to the termination of the treatment regimen (i.e., after 6 weeks). Results: Participants who received 180 mg of Ginkgo biloba extract EGb 761 daily for 6 weeks exhibited significantly more improvement on a task assess ing speed of processing abilities (i.e., Stroop Color and Word Test color-n aming task) by the end of treatment as compared to participants who receive d placebo. Trends favoring improved performances in the Ginkgo biloba group were also demonstrated in three of the four remaining tasks that involved a timed, speed of processing component, although they did not reach statist ical significance. Furthermore, a significant relationship was found betwee n the type of treatment (Ginkgo biloba extract or placebo) and participants ' ratings of their overall abilities to remember. Specifically, more partic ipants in the Ginkgo biloba extract group rated their overall abilities to remember by the end of treatment as "improved," as compared to the placebo group. Ln contrast, no significant differences were found between the Ginkg o biloba and placebo groups by treatment end on any of the four objective m emory measures. Conclusions: Taken together, the findings from standardized neuropsychologi c assessment and a subjective, self-report questionnaire suggested that rel atively short-term (i.e., 6 weeks) utilization of Ginkgo biloba extract EGb 761 may prove efficacious in enhancing certain neurocognitive functions/pr ocesses of cognitively intact older adults.