Hironori Sato

Physical activity group classification algorithm using triaxial acceleration and heart rate.

As described in this paper, a physical activity classification algorithm is proposed for energy expenditure estimation. The proposed algorithm can improve the classification accuracy using both the triaxial acceleration and heart rate. The optimal classification also contributes to improvement of the accuracy of the energy expenditures estimation. The proposed algorithm employs three indices: the heart rate reserve (%HRreserve), the filtered triaxial acceleration, and the ratio of filtered and unfiltered acceleration. The percentage HRreserve is calculated using the heart rate at rest condition and the maximum heart rate, which is calculated using Karvonen Formula. Using these three indices, a decision tree is constructed to classify physical activities into five classes: sedentary, household, moderate (excluding locomotive), locomotive, and vigorous. Evaluation results show that the average classification accuracy for 21 activities is 91%.

Design of a randomized controlled trial comparing a mobile phone-based hypertension health coaching application to home blood pressure monitoring alone: The Smart Hypertension Control Study

BACKGROUND Hypertension is a major cause of morbidity and mortality but frequently remains uncontrolled. A smartphone application that provides coaching regarding home blood pressure monitoring and other aspects of hypertension self-care and related behavior change may be a scalable way to help manage hypertension. METHODS/DESIGN The Smart Hypertension Control Study is a prospective, randomized controlled trial to assess the effects of a hypertension personal control program (HPCP), which consists of an automated artificial intelligence smartphone application that provides individualized support and coaching to promote home monitoring and healthy behavior changes related to hypertension self-management. Enrolled adults with uncontrolled hypertension will be randomized in a 1:1 fashion to the HPCP with home blood pressure monitoring or to home monitoring alone. We plan to enroll 350 participants, with a target of 300 participants with complete six-month follow-up data. The primary study outcome will be systolic blood pressure at six months. Additional outcomes include measures of antihypertensive medication adherence, home blood pressure monitoring practices, self-management practices, weight, and self-reported health behaviors. CONCLUSION The Smart Hypertension Control Study will evaluate blood pressure and hypertension self-management behavior outcomes in participants with uncontrolled hypertension exposed to a smartphone-based hypertension health coaching application in addition to home blood pressure monitoring compared to those exposed to home blood pressure monitoring alone.

Theoretical and Experimental Investigation of a Method to Detect an Aortic Aneurysm from Pulse Waves

Early identification of aortic aneurysms is important for effective treatment. Although imaging systems have the ability to identify aortic aneurysms, high cost prevents their use for screening. On the other hand, pulse waves can be measured easily, and because pulse wave velocity is affected by the aortic aneurysm, there is a possibility to find an aortic aneurysm by pulse wave measurement. The aim of this study is to propose a method to find an aortic aneurysm from the pulse wave and to develop a measurement device. The aortic aneurysm causes the expansion of artery. The basic theory is based on the wave of a mechanical reactance silencer. The transfer functions of a pulse wave between brachial artery and anterior tibial artery were investigated. The transmission loss is increased by increase of the inner radius of an aortic aneurysm. The interval frequency of local minimum points of the transfer function correlates with the length of an aortic aneurysm. When the stiffness decreases, the characteristic impedance decreases, the pulse wave velocity decreases and the frequencies of the local peaks become low. It is therefore possible to estimate the size of an aortic aneurysm from the transfer function. The method to find an aortic aneurysm from the pulse wave was investigated theoretically and experimentally with silicone tubes. The relation between the transfer function and the pathological arterial change was clarified. This method can be used for diagnosis of aortic aneurysms.