Effect of two doses of ginkgo biloba extract (EGb 761) on the dual-coding test in elderly subjects

Clin Ther. 1993 May-Jun;15(3):549-58.


The subjects of this double-blind study were 18 elderly men and women (mean age, 69.3 years) with slight age-related memory impairment. In a crossover-study design, each subject received placebo or an extract of Ginkgo biloba (EGb 761) (320 mg or 600 mg) 1 hour before performing a dual-coding test that measures the speed of information processing; the test consists of several coding series of drawings and words presented at decreasing times of 1920, 960, 480, 240, and 120 ms. The dual-coding phenomenon (a break point between coding verbal material and images) was demonstrated in all the tests. After placebo, the break point was observed at 960 ms and dual coding beginning at 1920 ms. After each dose of the ginkgo extract, the break point (at 480 ms) and dual coding (at 960 ms) were significantly shifted toward a shorter presentation time, indicating an improvement in the speed of information processing.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Ginkgo biloba
  • Humans
  • Male
  • Memory Disorders / drug therapy*
  • Mental Recall / drug effects
  • Middle Aged
  • Plant Extracts / therapeutic use*
  • Reaction Time / drug effects


  • Plant Extracts
  • Ginkgo biloba extract