New Vision of the Pulse Conditions Using Bi-Sensing Pulse Diagnosis Instrument

Yu-Feng Chung, Yu-Wen Chu, Cheng-Ying Chung, Chung-Shing Hu, Ching-Hsing Luo Department of Electrical Engineering

National Cheng Kung University Tainan 70101, Taiwan

Cheng-Chang Yeh Nanjing University of Chinese Medicine

Nanjing 210046, China

Abstract—Clinical experiences of pulse diagnosis are possible to be quantified and get rid of the viewpoint of nonscientific and subjectivity. The aim of this report wants to propose a new vision of pulse conditions by version 2 of Bi-Sensing Pulse Diagnosis Instrument (BSPDI V2). BSPDI V2 can repeat the pulse taking depth of physicians by displacement detection system, and mimic the fingertip sensations by pulse detection system. The 3-Dimension Pulse Mapping (3DPM) of pulse conditions can be constructed by BSPDI V2. Hence, the new vision platform of pulse conditions is to be built through BSPDI V2. Therefore, pulse conditions can be stereoscopic observation based on spatial and temporal dimensions. The more information and clearer outline of pulse conditions are to be explored, and the quantification of pulse patterns will much closer to fingertip sensations of physicians.

Keywords-pulse diagnosis; bi-sensing pulse diagnosis instrument; three dimenion pulse mapping; array sensor

I. INTRODUCTION Traditional Chinese medicine (TCM) protects Asian health

for thousands of years. However, the epoch-making change results in TCM frequently facing “medicine vanishing but herb” embarrassment. Even so, TCM still proves her invaluable and irreplaceable merits nowadays. TCM must be instructed seriously by the scientific protocol under the consideration of scientific validity, so TCM can catch the modern scientific research for the expectation of booming fast. Nevertheless, the recent two-decade researches of pulse diagnosis most are conducted under the base of cardio hemodynamics, resulting in a big gap between latest researches of pulse diagnosis and TCM methodologies inherited continuously for more than two thousand years.

There are four diagnostic methods in TCM: inspection, listening and smelling, inquiry, and palpation. Palpation is very important in clinical procedures, providing diagnostic measurements related to causes of disease, locations of disease, nature of disease, and predictions of cure [1]. Palpation, pulse diagnosis, can fast reflect the health state of patient. Hence, the last two decades have witnessed the growing importance placed on research in regard to the quantification of pulse diagnosis. The research fields can be divide into pulse taking instrument [2, 3], classification of pulse conditions [4, 5], the verification of pulse conditions [6, 7], etc. The analysis method roughly includes two parts: the time domain and the frequency domain. Many studies have defined a lot of parameters based

on wrist pulse waveform in time domain [8, 9]. These parameters include: the amplitude of a percussion wave, a tidal wave, and a dicrotic wave, etc. Frequency domain included two aspects: the distribution of energy [10], and resonance [11]. On the other hand, many researchers have developed classification methods (neural, fuzzy or neural-fuzzy, based on these parameters) to classify pulse conditions [12]. Many great results have been obtained so far; however, it does not integrate these parameters into clinical pulse-taking experiences.

Many kinds of sensors have been implemented to obtain information on wrist pulse [13]. These results were based on a single sensor with one sensing point. The information on wrist pulse has the limitation of being based on a single sensor. An array sensor must be developed if full information regarding wrist pulse is to be extracted [3]. The previous proposed BSPDI was created based on the criteria of Three Positions Nine Indicators (TPNI，三部九候) for TCM only [2]. Firstly, BSPDI can record and learn the finger-reading skill of physicians and fetch the TPNI pulse data with the recorded finger-reading skill at Fu-Zhong-Chen displacements on Cun-Guan-Chi positions. After the failure for seven years, BSPDI with single sensing point per position was implemented to successfully testify the pulse diagnosis rule of normal pulses proposed by Neijing, the first TCM scripture. This report wants to implement the array sensing points of BSPDI for the creation of 3DPM to provide the diagnosis by feeling visualized of pulse diagnosis as well as develop the tool of automatic classification of all kinds of pulses recorded in TCM scriptures.

II. MATERIALS AND METHODS This proposal integrated version 1of BSPDI and capacitive

array sensor to be BSPDI V2, more information can be referred to reference 2 and 3. Furthermore, the 3-Axis Automatic Positioning (3xAP) system is added in BSPDI V2. In this section, the version 2 of BSPDI, three-axis automatic positioning, pulse taking procedure, and the construction of three dimension pulse mapping are introduced.

A. Version 2 of Bi-Sensing Pulse Diagnosis Instrument The BSPDI V2 included three main parts: pulse detection

system (mimic fingertip sensations), displacement detection system (record pulse taking depth), and 3-Axis automatic positioning system. The pulse taking depths (Fu, Zhong, and Chen) of physicians can be recorded by strain gauge, and the robot fingertip will push down at these recorded depths to

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fetch wrist signals by capacitive array sensor for miming the fingertips sensations of physicians. The BSPDI V2 is shown in Fig. 1.

Pulse detection system

3-axis automatic positioning system

Displacement detection system

Pulse taking posture holder

Figure 1. Version 2 of Bi-Sensing Pulse Diagnosis Instrument (BSPDI V2) and holder of pulse taking posture. BSPDI V2 can record the pulse taking depths and mimic the fingertips sensations of physicians.

B. Pulse detection system: capacitive array sensor Twelve sensing elements are embedded in one robot

fingertip. The changed readout signal from capacitive array sensor represented the changed pressure on capacitive array sensor. Hence, the wrist artery signal can be detected by capacitive array sensor. The other mentioned point is that the static pressure can be also simultaneously detected during acquiring procedure. The example of readout signal is shown in Fig. 2. In Fig. 2, obviously the wrist signal of capacitive array sensor is same as that of single sensor in the literature. Hence, the proposed analysis techniques in the literature can be applied in future study.

Figure 2. The example of readout signal from capacitive array sensor. Twelve channel signals are detected, which includes dynamic pressure signals and static pressure signals.

C. Displacement detection system: strain gauge According to TCM, different pulse taking depths represent

different physiological meaning, the outline of pulse conditions are listed in Table I. For example, pulse conditions appear at Fu (Floating) that usually represents Yang pattern, conversely, that at Chen (Sunken) is Yin pattern. Hence, pulse condition has to be clearly descripted its appearance depth. Strain gauge of BSPDI V2 is implemented for this purpose. Firstly, physicians pressed his fingertips at Cun, Guan, and

Chi through different pulse taking depth level, such as Fu, Zhong, Chen, caused strain gauge that outputted different correspondence value. Then, BSPDI V2 recorded these values and token the pulse conditions based on recorded pulse taking depths. The structure of displacement detection system of BSPDI V2 is shown in Fig. 3. The detail information can refer to Luo’s report [2].

TABLE I. THE OUTLINE OF TRADITIONAL PULSE CONDITIONS

Book Outline

Shang Han Lun Large, Floating, Rapid, Stirrede, Slippery are YangSunken, Rough,Weak, String-like,Faint are Yin

Zhen Jia Shu Yao Floating, Sunken, Slow, Rapid, Slippery, Rough Bin Hu Mai Xue Floating, Sunken, Slow, Rapid Jing Yue Quan Shu Floating, Sunken, Slow, Rapid, Fine, Large, Short Zhen Jia Zhi Jue Position, Rate and Rhythm, Shape, Trend

Pulse detection system

Displacement detection system

Figure 3. The structure of displacement detection system of BSPDI V2. The readout signal of strain gauge represents hold-down pressure.

D. Three-axis automatic positioning The Three –axis Automatic Positioning (3xAP) is designed

to get the optimal pulse taking positions and depths. The X and Y axis could not adjust in the BSPDI V1 caused the optimal pulse taking position was hard to find. There are 11 stepping motors are integrated in the BSPDI V2. 9 stepping motors control three robot fingertips to take the pulse. 2 stepping motors control up-down and forward-backward of pulse taking platform. The 3xAP can automatic find the optimal pulse taking position by proposed algorithm and guarantee the strongest sensing area to locate at the center of capacitive array sensor. The structure of 3xAP is shown in Fig. 1.

E. Pulse taking procedure The experiment protocol included 5 steps. In step 1, the

participants were asked to sit on an adjustable chair. Physicians checked all participants to confirm pulse conditions and pulse taking positions. In step 2, The participant’s wrist was put under displacement sensors, and a physician pushed his/her three fingertips on top of the displacement sensors to touch the Cun, Guan, and Chi positions of the participant. The displacement detection system obtained the participant’s pulse taking depths at Fu, Zhong, and Chen, while the physician checked and recorded the participant’s individual pulse conditions. In step 3, the participant’s wrist pulses at the obtained pulse taking depths (Fu, Zhong, and Chen) were measured by pulse detection system of BSPDI V2. The

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participant changed the other hand to sample wrist pulse and repeat step 2 to step 3. In step 4, Daubechies wavelets was used to remove the baseline wander. In step 5, a 3DPM was formed from 12 pulse signals measured by 12 sensors in an array. The forming algorithm of 3DPM was revised from Luo’s report, the detail information can be referred to reference [14] and next sub-section.

F. Three-Dimension Pulse Mapping construction The 3-Dimension Pulse Mapping (3DPM) can be

constructed by these 12 channel signals of one capacitive array sensor. In this proposal, the polynomial surface fitting equation is chosen to represent the wrist pulse of twelve channels.

( ) 303

212

221

20211

220011000, ypxypyxpypxypxpypxppyxVpp ++++++++=

(1)

where x represents the width axis of pulse conditions, and y represents the length axis of the pulse conditions.

xxp represents the surface fitting coefficient. 3DPM can be observed by different spatial and temporal dimension.

III. RESULTS

A. Pulse taking detection system The pulse taking detection system provided both dynamic

wrist artery information and static hold-down pressure, as shown in Fig. 2. In addition, the 3DPM can be constructed based on capacitive array sensor, and the conventional pulse waveform in 2-dimension also can be obtained from BSPDI V2. The example of acquired signal in 2-dimension and 3-dimension format are shown in Fig. 4. Hence, pulse conditions can be observed both in 3-dimension and 2-dimension. The width and length of pulse conditions are easier to be observed and more quantifiable information of pulse conditions can be explored from 3DPM.

(a)

Am

plitu

de (m

V)

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Figure 4. The example of acquired signal from BSPDI V2 in (a) 2-dimension and (b) 3-dimension (3DPM).

B. Three-Dimension Pulse Mapping The observation platform is built up to explore the full

information of pulse conditions. The spatial characteristics of pulse conditions can be viewed in 3DPM, as shown in Fig. 5. Researchers can find out the specific characteristics of target pulse conditions in free angle or fixed step angle.

Figure 5. The spatial dimension of 3DPM to explore the mysterious phenomenon of pulse conditions. The observed interval angle is 90 degree.

In addition, the pulse conditions can be observed in temporal dimension. The observation in temporal dimension is directed in relation to fingertip’s sensations of physicians. Hence, the observation in temporal dimension of pulse conditions is very important for understanding the dynamic characteristics of pulse conditions. The example of temporal observation is shown in Fig. 6. Similarly, researchers can setup the observed interval as fixed time or free time.

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Figure 6. The temporal dimension of 3DPM to explore the mysterious phyenomenon of pulse conditions.

IV. DISCUSSIONS AND CONCLUSIONS

A. The Performance of Proposed Pulse Taking Platform BSPDI V2 was designed to duplicate the fingertips

sensation and pulse taking depths of physicians. The integration is successful between pulse detection system (capacitive array sensor) and displacement detection system (strain gauge). Using BSPDI V2, researchers can elaborate the methodology of pulse diagnosis, and the subjectivity of pulse conditions will transfer to objectivity and visualization. On the other hand, the pulse taking of BSPDI V2 is automatic by 11 stepping motors to shorten the pulse taking period.

B. Three-Dimension Pulse Mapping Pulse diagnosis suffers from non-scientific and subjectivity

for a long time. If the fingertips sensation can be viewed in the monitor like as western medical instrument, then the subjectivity will be alleviated. BSPDI V2 is successful not only to implement this requirements but also to construct spatial and temporal observed platform. It is very useful tool for exploring the full information of pulse conditions before researchers start to analyze the quantifiable parameters of pulse conditions.

ACKNOWLEDGMENT This work is supported by Center of Advanced Biomedical

System Center, NCKU. The authors would like to thank Dr. Ming-Hong Tsai and Mr. Hsin-En Fang for building BSPDI V2.

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