An objective review of the technological developments for radial pulse diagnosis in Traditional Chinese Medicine

IntroductionPulse palpation is an important diagnostic tool in Traditional Chinese Medicine (TCM) and related Oriental medicine systems. However, mastering pulse diagnosis requires long-term experience and remains subjective up to a certain degree even in an advanced stage of practice. Accordingly, considerable research efforts have been spent to objectively measure the radial pulse and in further consequence automate Oriental pulse diagnosis by means of technological aids. This article gives the first comprehensive review about the current state of the art of this field covering topics such as developed pulse acquisition systems, suggested data preprocessing and feature extraction methods, and proposed classification approaches. Furthermore, persisting problems are pointed out and recommendations for future research directions are given.MethodsA literature search was conducted using scientific databases such as PubMed and ScienceDirect. ResearchGate, Academia, and GoogleScholar were used as additional literature sources. Key search terms were Chinese pulse diagnosis, Oriental pulse diagnosis, wrist pulse, standardization, objectification, automation, technological aids, sensors, data processing, classification, devices, acquisition systems and combinations and synonyms of these terms. Additionally, the reference lists of found articles were scanned to identify further relevant literature.ResultsA total of 111 references were included into the review. Four main research themes emerged from the literature: (1) pulse waveform acquisition, (2) pulse waveform preprocessing, (3) pulse waveform feature extraction, (4) classifiers and classification objectives.ConclusionAutomating TCM pulse diagnosis by means of technological aids is a very active research field. Nevertheless, much remains to be done in terms of both technological developments and standardization of procedures.