Development of an evidence-based Chinese herbal medicine for the management of vascular dementia

Autor: Liu, Junguang, University of Western Sydney, College of Health and Science, Centre for Complementary Medicine
Jazyk: angličtina
Rok vydání: 2008
Předmět:
Popis: Vascular dementia (VaD), the second most common cause of dementia, causes substantial distress to patients and represents a significant burden to their families and communities. Currently, there is no effective treatment to reverse the brain damage associated with VaD. In general the drugs available for the management of cognitive problems in VaD are expensive and outcomes are uncertain. It is, therefore, important to seek out alternative approaches, which may prove effective, cheaper and safer. Chinese herbal medicine (CHM) has been used for the treatment of dementia-like disorders for centuries. Data from many preclinical studies and some clinical studies have suggested the potential effectiveness of CHM for the treatment of VaD. Based on the literature review conducted as part of this thesis, however, most of the studies were published in Chinese literature and failed to demonstrate methodological rigour or to report sufficient methodological detail. Randomised controlled trials (RCTs) using scientific methods of diagnosis and outcome measures are urgently needed. Wei Nao Kang (WNK) is a three-herb formula developed by Xi Yuan Hospital, China Academy of Chinese Medical Sciences. Preclinical experiments of WNK have demonstrated significant improvement in learning and memory function in VaD animal models in rats and mice. Human case studies have also signalled the potential value of WNK in VaD. Although the results of these studies were encouraging, strong scientific evidence from a well-designed RCT is still required. A rigorous clinical trial methodology, including scientific diagnostic criteria and outcome measures, was designed and applied to the evaluation of WNK for VaD. The trial was successfully conducted over a two-year period. Cognitive functions, as evidenced by the ADAS-cog, were significantly improved in the study group taking WNK herbal medication compared with the placebo group. The ADAS-cog was simultaneously validated as a measure of cognitive function in VaD. Blinding was verified and no major adverse effects were found related to WNK treatment. However, neither group demonstrated long-lasting effect on a 16 weeks follow-up after completion of treatment. WNK demonstrated a significant effect on quality of life (measured by SF-36) and some effect on activities of daily living (measured by ADCS-ADL) in VaD patients. The SF-36 was validated as a measure of general health status and the ADCS-ADL as a measure of activities of daily living in patients with VaD. Both scales were proven sensitive to the presence of VaD, and provided useful supplementary outcome measures for VaD. A cerebral perfusion study was conducted to identify changes in cerebral blood flow and its relationship with clinical symptoms. The study showed that WNK had marked increases in blood flow in the inferior frontal and anterior temporal regions, both of which are closely related to cognitive function in human brains. This study has provided scientific evidence in support of the clinical effect of WNK on VaD. In addition, it validated several outcome measures in assessing improvements in cognitive functions, activities of daily living and quality of life in VaD patients. One of the highlights of this study is the application of SPECT scans as an outcome measure. This provided an excellent objective parameter for assessing the effects of WNK. To the best of our knowledge, SPECT scanning has never been used in VaD trials of herbal medicines.
Doctor of Philosophy (PhD)
Databáze: Networked Digital Library of Theses & Dissertations
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