An earbud-type wearable (A hearable) with vital parameter sensors for early detection and prevention of heat-stroke - overview


Contributors : Keiji Matsumoto1, Takahito Watanabe1, Eiji Nakamura1, Hiroyuki Mori1
Patrick Ruch2, Yuksel Temiz2, Bruno Michel2 , Sufi Zafar3, Hamidreza Taghavi4, Elrick L. Cornelius4
1IBM Research-Tokyo, 2IBM Research-Zurich, 3IBM T. J. Watson Research Center, 4Sonion,
 
Summary :
Heat-stroke has become a serious problem in Japan, especially for elderly citizens. For the early detection and prevention of heat-stroke, a wearable health monitor for in-ear use is developed which is subsequently called “Hearable”. It aims to measure three vital parameters: Core body temperature, sweat rate and interstitial sodium ion (Na+) concentration. The eardrum is a good place to measure the core body temperature, because it is close to the carotid artery and the brain. We develop a hearable prototype and it consists of an audio earbud, a sensor earbud and a micro controller. Concerning the sensor earbud, a present prototype includes an eardrum (tympanic) temperature sensor and a sweat rate sensor. We demonstrate the monitoring of the eardrum temperature and the sweat rate to differentiate a calm state and jogging. Concerning interstitial sodium ion (Na+) concentration, we perform fundamental study. There have been several technical challenges, as follows. Firstly, needle-type electrodes with pain are not preferable. Secondly, measured Na+ concentration depends on how deep the needles penetrate. We solve these challenges by focusing on the epidermal fluid. There is a region called epidermis, which is 300m deep from the surface of the body, where one doesn’t feel pain. If we can make a needle-type electrode which penetrates the constant depth of the epidermis, we can realize a consistent (reproducible) and pain-less Na+ sensor. For the purpose, we evaluate the contact resistance between a needle-type electrode and the epidermis as function of the penetration depth and show that the contact resistance is an indicator of the penetration depth. Thus, it is possible to keep the penetration depth of needle-type electrodes constant, based on the contact resistance. It leads to consistent (reproducible) measurement of Na+ concentration in the epidermis.
 
Publications (2)
Conference name : MES 2018 (MicroElectronics Symposium)
Status : Presented.
Paper title : Investigation on the practical needle-type wearable Na+ sensor.
Authors : Keiji Matsumoto1, Takahito Watanabe1, Eiji Nakamura1, Hiroyuki Mori1
Patrick Ruch2, Sufi Zafar3
1IBM Research-Tokyo, 2IBM Research-Zurich, 3IBM T. J. Watson Research Center,
 
Conference name : 41st EMBC 2019 (Engineering in Medicine and Biology)
Status : Accepted.
Paper title : An earbud-type wearable (A hearable) with vital parameter sensors for early detection and prevention of heat-stroke.
Authors : Keiji Matsumoto1, Yuksel Temiz2,  Hamidreza Taghavi3, Elrick L. Cornelius3, Hiroyuki Mori1, and Bruno Michel2
1IBM Research-Tokyo, 2IBM Research-Zurich, 3Sonion,