Herbal Medicine for Vascular Dementia: An Overview of Systematic Reviews

Introduction: Vascular dementia (VaD), a severe neurologic condition related to aging of the cerebrovascular structure, has been treated with herbal medications and products. In this overview of systematic reviews (SRs) on the effects of herbal medications, we aimed to summarize the current clinical evidence on the benefits of herbal drugs and to propose an evidence map outlining their effects on VaD. Methods: SRs assessing their effects on cognitive function or performance and the associated safety, published until December 2018, were located from PubMed, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, China National Knowledge Infrastructure, and Oriental Medicine Advanced Searching Integrated System. A Measurement Tool to Assess systematic Reviews 2 was used to assess their overall confidence. A bubble plot was proposed to present the depth and width of the current status of the evidence supporting the use of individual herbal drugs. Results: Ten SRs (4 on individual herbal medications and 6 on various herbal drugs) were included. The overall evidence on herbal medicines suggests that they are effective in improving cognitive function and performance. Individual herbal medications including FuFangHaiShe, NaoXinTong, YinDanXing- NaoTong, NaoMaiTai, ShenFuTang, and TongXinLuo showed favourable effects when assessed via a minimal mental state examination score but have limited evidence supporting their effectiveness due to the scarcity of randomized controlled trials. Concerning safety, most SRs did not outline the estimated risk ratio of adverse events. Conclusions: Herbal medications might have benefits for VaD patients but they need to be evaluated further.