An Overview of Systematic Reviews of Ginkgo biloba Extracts for Mild Cognitive Impairment and Dementia

Abstract

Ginkgo biloba extracts (GBEs) have been recommended to improve cognitive function and to prevent cognitive decline, but earlier evidence was inconclusive. Here, we evaluated all systematic reviews of GBEs for prevention of cognitive decline, and intervention of mild cognitive impairment (MCI) and dementia. Six databases from their inception to September 2015 were searched. Ten systematic reviews were identified, including reviews about Alzheimer's disease (n = 3), about vascular dementia (n = 1), about both Alzheimer's disease and vascular dementia (n = 2), about Alzheimer's disease, vascular dementia and mixed dementia (n = 3), and a review about MCI (n = 1). Based on the overview quality assessment questionnaire, eight studies were scored with at least 5 points, while the other two scored 4 points and 3 points, respectively. Medication with GBEs showed improvement in cognition, neuropsychiatric symptoms, and daily activities, and the effect was dose-dependent. Efficacy was convincingly demonstrated only when high daily dose (240 mg) was applied. Compared with placebo, overall adverse events and serious adverse events were at the same level as placebo, with less adverse events in favor of GBE in the subgroup of Alzheimer's disease patients, and fewer incidences in vertigo, tinnitus, angina pectoris, and headache. In conclusion, there is clear evidence to support the efficacy of GBEs for MCI and dementia, whereas the question on efficacy to prevent cognitive decline is still open. In addition, GBEs seem to be generally safe.

Vascular cognitive impairment and chronic cerebral ischemia (dyscirculatory encephalopathy)

“…В рекомендациях, подготовленных экспертами США, ноотропные, вазоактивные и метаболические средства, ан-тиоксиданты не расцениваются как эффективные при СКН [2]. Однако во многих современных обзорах по лечению СКН встречаются данные о положительном действии церебролизина при выраженных СКН по результатам метаанализа [58], препарата EGB 761 -по данным систематического обзора [59], актовегина при постинсультных КН -по результатам многоцентрового рандомизированного плацебоконтролируемого исследования [60].…”

Mild Cognitive Impairment

“…Yang et al conducted meta-analysis of randomized clinical trials on Ginkgo biloba in treating mild cognitive impairment or Alzheimer's disease. Data from 21 trials with 2608 patients have been analyzed [39].…”

“…According to the review of studies on older subjects with MCI reported some positive effect of physical exercise on cognition, mainly on global cognition, executive function, attention and delayed recall. However, most studies performed in older subjects with dementia showed no effect of exercise on cognition [39].…”

“…Mitchell and Shiri-Feshki analyzed 41 high-quality cohort studies. They have found that the annual conversion rate (ACR) from MCI to dementia is approximately 5-10% and most people with MCI will not progress to dementia even after 10 years of follow-up [39]. The cumulative risk over 10 years ranged between 30 and 50%, depending on whether the studies that were analyzed used a definition of MCI that included subjective memory complaints.…”

Poststroke cognitive impairment: diagnosis and treatment

“…Результаты клинического исследования, в котором участвовали пациенты с умеренными сосудистыми КН, продемонстрировали улучшение когнитивных функций и кровоснабжения головного мозга на фоне терапии EGB 761 ® в течение 3 мес [55]. В недавнем метаанализе 10 систематических обзоров эффективности и безопасности EGB 761 ® у пациентов с деменцией и умеренными КН сделан вывод, что препарат улучшает когнитивные функции и повседневную двигательную активность у пациентов с умеренными КН [56].…”