Fuzzy controller design for Estimation of Systolic area in PPG signal by Persian medicine

Introduction: Photoplethysmogram (PPG) is a method for measuring blood volume changes per pulse and is widely used in healthcare. On the other hand, Persian medicine (PM) pulsology is one of the most important methods of clinical diagnosis. In this research, by using the potential of fuzzy systems, it has tried to establish a relationship between PPG signal indicators in the systolic area and PM pulsology. Methods: The theory of fuzzy sets is a very applicable basis for the development of knowledge-based systems in medical studies . To design the fuzzy controller, the pulse information as well as the PPG signal was simultaneously recorded using 55 individuals by a PM specialist. First, the rules were created using input-output variables. Also, by keeping the rules to the highest degree and removing the rest of the rules, 35 rules remained which was shown in the form of a lookup table in two-input-one-output mode. Results: The fuzzy system with 35 rules, triangular and trapezoidal membership functions, singleton fuzzifier, product inference engine, and center average defuzzifier was designed by MATLAB software. This system with two inputs of pulse frequency and pulse strength, as well as an output of systolic area, has an acceptable efficiency in the defined range of inputs. conclusion: This fuzzy controller system provides a reasonable estimate of the systolic area of the PPG signal using PM pulse parameters, and it was observed that increasing the pulse frequency decreases the systolic area and also increasing the pulse power increases the systolic area, which is consistent with the results of previous studies. Therefore, it can be used to help increase the clinical skills of PM students and practitioners. This can also be promising to be applied in the diagnosis and prediction of diseases, as well as to establish communication between PM and mainstream medicine.