Table 5: Selected Ginkgo Biloba Clinical Trials.     
 Author Trial Design Subjects Daily Dose Outcome Measures Results
GraBel
(1992) 		DBPC
24 weeks

N=72
Age not reported
Memory impairment

 Ginkgo biloba extract
160 mg
  • Psychometric computer aided examination of short term memory
  • Basic learning ratio

Significant improvement in both outcome measures in the Ginkgo biloba-treated patients
Allain
(1993) 		PC
Single dose		 N=18
Mean age 69.3 years
Age-related memory impairment		 Ginkgo biloba in combination products

320- or 600-mg prior to performance
  • Dual-coding test
    • Evaluates memory coding of verbal material and images in relation to variable presentation times
 Significant improvement in the dual-coding test in the Ginkgo biloba-treated patients (p=0.0001)
Subhan
(1984) 		Cross-over
DBPC
Single dose		 N=8
Mean age 32 years
Healthy females		 Ginkgo biloba in combination products

120-, 240-, 600-mg prior to performance
  • Critical flicker fusion
  • Choice reaction time
  • Subjective rating of drug effects
  • Sternberg Memory Scanning Test

No difference in any outcome measure, except in the Sternberg Memory Scanning Test

  • Significant difference with Ginkgo biloba
    600 mg dose
Rai
(1991) 		DBPC
24 weeks		 N=27
Aged 54 to 89 years
Mild to moderate
memory impairment		 Ginkgo biloba in combination products

120 mg
  • Cognitive function
  • Digit copying subtest of the Kendrich Battery
  • Median reaction time
  • Digit recall test
  • Mini-mental state exam
  • Critical flicker finding
  • Classification task
  • EEG
  • Latency of auditory event-related potential
 No difference in any outcome measure, except a significant improvement in the cognitive function and digit-copying subtest of the Kendrich Battery in the Ginkgo biloba-treated patients at both week 12 (p=0.022) and week 24 (p=0.017).
Semlitsch
(1995) 		DBPC
57 days		 N=48
Aged 51 to 79 years
Age-related memory impairment		 Ginkgo biloba in combination products

120 mg
  • EEG
  • Subjective psychometric tests of well-being
  • Increase in normal age associated P300 latency prolongation on the EEG (neuronal activity indexed by P300 latency reflects evaluation time and speed of stimulus during memory updating) in Ginkgo biloba-treated patients
  • No difference in the subjective psychometric tests of well-being
LeBars
(1997)		 RDBPC
52 weeks		 N=327
Mild to severe dementia
(Alzheimer's Disease or infarct dementia)		 Ginkgo biloba or Placebo

40 mg TID
  • ADAS-Cog
    (Alzheimer's Disease Assessment Scale-Cognitive subscale)
  • GERRI (Geriatric Evaluation by Relative Rating Instrument)
  • Cognitive performance
  • Social functioning
  • Ginkgo biloba-treated patients scored 1.4 points higher on the ADAS-Cog (p=0>04)
  • Ginkgo biloba-treated patients scored 0.14 points higher on the GERRI (p=0.004)
Solomon
(2002) 		RDBPC
Parallel group
6 weeks		 N=219
Mean age 69.3 years
MMSE scores > 26 and good health 		Ginkgo biloba or Placebo

40 mg TID
  • California Verbal Learning Test
  • Logical Memory subscale of Wechsler Memory Scale Revised (WAIS-R)
  • Vision Reproduction subscale
  • Digit Symbol subscale of WAIS-R
  • Stroop Test
  • Digit Span
  • Mental Control
  • Controlled Category Fluency Test
  • Boston Naming Test
  • Memory Questionnaire
  • Global Evaluation
 No signficant difference for any outcome measure
RDBPC= randomized, double-blind, placebo-controlled; DBPC= double-blind, placebo-controlled, PC= placebo-controlled; MMSE= Mini Mental State Exam;     TID= three times daily

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