Current challenge for traditional Chinese medicine
Traditional Chinese medicine (TCM) was conceived thousands of years ago and has evolved through continuous practice and refinement via its application to patients and to health maintenance. Although TCM is now practiced in many countries and has been proposed to possess great potential to improve people’s health and wellness, it is still challenged by scientific interpretation and well-recognized high level clinical evidence for its effectiveness. Many reasons that make the quantification of TCM an ongoing challenge exist.
P. W. Anderson proposed the hierarchical structure of science [
1]. Western medicine is a good example of following laws, and it most often takes a reductionist approach, i.e., breaking down the body into ever-smaller parts in order to understand its inner workings and profound mechanisms. To better understand the human body, the scientific world has been going in the direction of microscopic levels. As a result, tremendous knowledge has been gleaned on anatomy, physiology, pathology, histology, genetics, and biochemistry. However, when different parts of the body are involved as a whole system, understanding of how the system works is still limited.
Western medicine is considered as “pure science,” whereas TCM is based on broad range of philosophical concepts and such concepts are a part of TCM’s manner of development. TCM embraces theories from philosophy and culture, gradually developing to complex theoretical frameworks, including Yin-Yang Theory, 5 elements, 8 principles, Zang-Fu organs, Qi and Blood, the meridian systems, as well as multiple therapeutic approaches. These frameworks seem too abstract to people who have little sense of the ancient traditional Chinese philosophy. In addition, TCM highlights individualized practice, which is sometimes considered or even criticized as non-standardized treatment by people who fail to grasp the TCM practice of following simple rules.
Traditional medicine and western medicine originated and developed within different contexts and perspectives of the natural world (Fig. 1). Although the constructionist hypothesis fails when confronted with scale and complexity [
1], traditional medicine is often criticized for its lack of scientific proof rather than be credited for its holistic views. As western medicine dominates health care in the modern world, scientifically proving the efficacy of TCM is necessary. On one hand, this should be a positive driving force for TCM modernization, thereby increasing acceptability. On the other hand, questions on specific methods used to aid this process arise. Is it as simple as to utilize frontier scientific measures, thereby indiscriminately using the same measuring system in western medicine for TCM evaluations? Modern technologies have provided powerful clinical indicators with very specific targets, biomarkers or imaging sensitivity, which were designed to show a specific change in a certain level, at a certain specific time point. In western medicine, those indicators have significant meanings or associations with targeted change, from organs, tissue, cells, to genes and molecules. Even with such advancement, western medicine used to be criticized by using linear fallacy with a widely held assumption that biological systems can be largely understood by dissecting micro-components or modules and analyzing them in isolation [
2–
5]. There is insufficient evidence that changes in microscopic scale are associated with TCM diagnosis and treatment. Unfortunately, it is the TCM dilemma that is considered in most cases. As Dr. Leshner pointed out, traditional medicine researchers are applying modern 'omics and the latest technologies in an attempt to standardize traditional treatments [
6].
To reasonably expand our knowledge and further evaluate TCM’s effectiveness, we need to place ourselves in or around the TCM scales and try to find or develop feasible measurements. Although reductionism is still dominant in the West, some have started to combine theories from a variety of disciplines. Consequently, a gratifying trend of developing an expanded system view of medicine is now present. Systems-based theories have the potential to bridge the East and the West and ancient and modern ideas; systems biology is proposed as such an approach [
7]. TCM has well-known features of dynamic, complex, fractal, and balanced/harmonious at system-level views. Therefore, to scientifically study TCM and evaluate its efficacy while preserving its strength and unique framework, we need to utilize or develop quantitative approaches that can offer system-level views and evaluations. In this article, we will briefly introduce the basis and features of TCM and propose a potentially promising approach to TCM quantification and evaluation. This may add more possible tools in the future to increase the acceptability of TCM in this modern society.
The art of TCM and the science of dynamical complexity
Holism and dynamical systematic views
TCM is only marginally concerned with anatomical structures of the human body. Instead, it primarily considered the body as a complex and dynamic system. TCM emphasizes not only the regulation of the human body, but also the integrity of its functions and its interaction with the ever-changing environments. The entire concept is known as holism, where health is perceived as balanced regulation and harmonious interaction. Disease is interpreted as internal disharmony or imbalance in body functions or interactions.
In dynamical complexity theories, a healthy body has the best chance to survive and adapt to external challenges (stresses) when it is able to keep internal balance [
8–
10]. Therefore, biological systems should evolve to increase their dynamic capacity or complexity. Today, biological systems we observe are highly complex, because they are the products of a very long evolutionary process. From this point of view, a meaningful quantification of the complexity of a biological system should be related to the system’s capacity to adapt and function in an ever-changing environment [
11].
With this consistent fundamental concept of TCM and dynamic complexity theories, the system-level approach becomes feasible in understanding TCM and designing TCM research. Utilizing the output of biological systems can exhibit the complexity in a dynamic manner [
10,
12]. However, biological systems are always with multiple interacting components that remarkably complicate the dynamic fluctuations in the output. This is the reason why such fluctuations have long been ignored by conventional analyses. Now, by applying the
fluctuation dissipation theorem concept [
13], we can simply measure the spontaneous fluctuations of a system in the state space when it is under free-running condition, and use that information to predict the ability that a system can adapt when encounters a challenge. Consequently, our task of defining a system’s complexity can be dramatically simplified.
Balance between two extremes
Viewing the human body at broader temporal scales in TCM, a healthy human body is considered as able to dynamically change toward a balanced state. The occurrence of a disease is essentially the outcome of the superiority (excess) or inferiority (deficiency) of one side because of the destruction of their relative balance. However, balance is never as simple as “more or less” or “one overweighs another” in TCM. Instead it involves the dialectical thoughts from Chinese philosophy. In simple cases, “eliminating the surplus” and “supplementing the deficient” are the principles of coordinating yin and yang. These coordinating yin and yang principles reduce the excessiveness and reinforce the deficiency, respectively. In many cases, there will be further argumentations involved.
Although complexity indicates the capability to adapt to challenges, it is not a one-directional approach. Current complexity science believes that a well-adaptive system is intermediate between too much order and total randomness. The degree of order and randomness is typically assessed using entropy-based methods by quantifying the regularity of a time series. In early approaches, entropy increases in correlation with irregularity, reaching a maximum in completely random systems (Fig. 2). These systems yielded contradictory results, where a high degree of entropy is observed under certain pathological conditions. A more popular and meaningful approach is a measure that is justified between order and randomness (Fig. 2). One such measure is to quantify entropy over multiple time scales, also known as multiscale entropy (MSE) [
8,
10,
12]. Based on the well-established theory and real world practice, it is now believed that healthy dynamics poised between too much order and total randomness. Aging and pathological conditions will degrade a system’s complexity since they represent a less adapted system.
These fundamental concepts, again, are very consistent. The Chinese balance theory actually permeates every level of the real world, e.g., in traditional diet, culture, exercise, art, literature, music, moods, and religion. Great examples in complexity science indicate that good literature, music, and healthy mood are all complex, but neither too ordered nor too random. To many levels we can think of, complexity has proposed surprisingly similar concepts as traditional Chinese concepts. From there, we expect complexity science to bring new insights into TCM in the near future.
Examples of applications
Complexity science was established in the late 19th century, and has been significantly developed in recent decades. The concepts of complexity have been applied to the pioneering studies of cardiac electrical activities [
8,
12]. Since the underlying rules are universal, complexity theories rapidly spread to many fields in medicine. Physiological signals are the most complex in nature, and rich information is hidden (encoded) in these fluctuations. It has long been observed that physiological output under healthy conditions typically exhibits multi-scale complexity, long-range correlation, and nonlinearity [
14].
The complexity approach has great potential among populations in various settings and in multiple studies, including biomedical fields, such as cardiology, pulmonology, neurology, endocrinology, nephrology, geriatrics, obstetrics and gynecology, orthopedics, psychiatry, psychology, physiology, and pathology. The multiscale entropy (MSE) approach has been widely used as a measure of complexity in medicine and has improved our understanding of human body and how it functions. MSE-based measurements have been used in heart beats, pulse waves, blood pressure, respiration, brain activities, neuroimaging, body temperature, muscle activity, center of pressure (COP) of body sway, human gait, bone and cartilage, and mood or mental stability.
Dynamic complexity was proposed with great potential value in TCM [
15]. In examples from previous studies [
15], MSE can reveal subtle changes in standing postural control in older adults with peripheral neuropathy [
16] and in the body balance dynamics [
17] after Tai Chi training. Without sensitive measurements like this, effects of alternative therapies like Tai Chi may not be revealed scientifically. In fact, MSE and other complexity measures are believed to be valuable in quantifying physiological functions and evaluations from multiple aspects [
18–
24], including research in the brain or mental health [
25,
26]. By the late 20th century, research on the human brain had become a fascinating interdisciplinary science. It expanded beyond the fields of psychiatry, neurology, and neuroscience, and involved concepts from mathematics, physics, and computer science. In this new century, dynamic complexity theories will be increasingly applied to the study of the brain and the dysfunctions associated with the mentally ill.
Discussion
Because of the origins and driving forces of development, practicing western medicine required the understanding of the body for fixed somatic structures. In the past decades, reductionism forced western medicine to investigate the human body at microscopic scales. Meanwhile, TCM maintained the practice of tracing symptoms and study patterns of underlying disharmony by assessing the human body as a whole. Nowadays, modern technologies have provided powerful tools and strong evidence for western medicine, with clear targets. For traditional medicine, the therapeutic framework and clinical practice were different from those of western medicine, and the need for scientific evaluation is a challenge to TCM. It is surely important to expand understanding of traditional medicine and prove its effectiveness by utilizing frontier scientific measures, but indiscriminately copying the same measuring system may not be applicable.
For a long time, optimal randomized control trials are a controversial topic in TCM because of extreme emphasis and overly narrowed fixed important and considerable parameters, which researchers consider important and valuable. Even the outcome measures are debatable. In an example, red blood cell, hematocrit, hemoglobin, and ferritin are used as direct indicators for iron deficiency anemia, but are not necessarily associated with symptoms defined by the so-called pattern Blood Deficiency. Far beyond this, body dynamics including biological rhythms are frequently noted issues when measure only at a single time point, particularly in the real world. Therefore, a long way is ahead before the systems biology could interpret TCM. An integrated, network-based system for alternative health care or systems biology for clinical TCM research can be applied only when the foundation was laid solid.
Reductionism is gradually declining as a dominant methodology in modern biomedical research. People around the world are realizing that while we can learn much from understanding the finest details at a molecular level, particularly when it comes to treating disease, a deeper knowledge of the interactions between systems and networks is essential. TCM is valued for its holistic view of the human body, which is a balanced, dynamic, complex whole at a system level. All the features are highly emphasized in dynamical complexity theories. Although TCM is not yet involved in many applications, existing successful examples improve future potential.
Higher Education Press and Springer-Verlag Berlin Heidelberg
PDF
(309KB)
