A reliability test for the body constitution diagnosis using wrist pulse analysis based on Ayurveda

Abstract

Wrist pulse diagnosis is the most primitive and apparent way to know about the human body condition for the diagnosis of disease. Ayurveda, an ancient Indian science, introduced wrist pulse diagnosis in the name of ‘Nadi’. Due to the lack of expertise and standardisation, the knowledge of Nadi is limited to very few Ayurvedic practitioners. An automated wrist pulse reading instrument can overcome this problem and help in non-invasive diagnosis using a wrist pulse based on Ayurveda. The primary objective of the research is to develop instrumentation to digitise the three pulse patterns viz., Vata (V), Pitta (P) and Kapha (K). Based on the signals acquired, the nature of the body (Prakriti) is identified and categorised into different classes. Wrist pulses are acquired using three thin-film flexible piezoelectric sensors and processed using a signal conditioning circuit. Signals are quantised using data acquisition module and processed. The studies carried out in the present work show substantial to moderate (based on the number of classes considered) agreement in the pulse-based classifications done by expert Ayurvedic physician and the developed instrument. Cohen's kappa of 0.719 and 0.454 are obtained as inter-rater reliability between traditional and instrumental readings on wrist pulse taken on basic level (VPK) and sub-levels (VP, VK & PK). An inter-rater reliability test using Cohen’s Kappa is adopted for this purpose. Similarly, reliability between Ayurvedic questionnaire-based and wrist pulse-based Prakriti identification are also tested. A Cohen's kappa of 0.587 and 0.476 is obtained between Prakriti and two different pulse reading data sets with basic level of classification viz. instrument and traditional method.