Energy-efficient Long Term Physiological Monitoring GeM-REM Energy-efficient Long Term Physiological Monitoring Ayan Banerjee, Sandeep Gupta Arizona State University Sidharth Nabar, Radha Poovendran University of Washington, Seattle Clinical Collaborator: Dr. Barbara Cochrane, UW School of Nursing

Long Term Monitoring Solution Sensor Platform ECG Leads Wireless Link Base Station Physician 1. Low Energy 2. Small Batteries 3. Low Memory 4. Simple processing 1. Low Bandwidth Usage 2. Robust to Wireless Errors Storage Efficient Data Annotation High Fidelity Data Quick Review Keep alive Sensor Module Model Sensed ECG Compare Match? Model Base Station Module Raw ECG samples Align Output ECG Raw signal updates Feature updates Wireless Link

Example Operation 42:1 93% Reduction in data transmission Periodic Signal Update Low Battery Lifetime (3 hrs)[1] High Storage (7.2 GB per month) Bandwidth Usage 82 kbps Scan ______ samples per day High Fidelity Data, transmitted at 82 kbps 3 lead ECG 1.2 0.4 -0.4 200 400 600 800 1000 1200 1400 Baseline and expected variations (feature updates) Arrhythmia probability of occurrence = 0.0097 [2] (raw signal update) Baseline and expected variations (feature updates) Diagnostically Equivalent Data at 1.166 kbps High Fidelity Data at 82 kbps Diagnostically Equivalent Data at 1.166 kbps Prolonged Battery Life (126 hrs) Low Storage (175 MB per month) Low Bandwidth Usage 1.95 kbps Annotated ECG GeM-REM Reduction in data transmission Diagnostic Feature Accuracy 42:1 93% [1] Munshi et al. "Wireless ECG plaster for body sensor network," Medical Devices and Biosensors, 2008. ISSS-MDBS 2008 [2] Martinelli et al. “Probability of occurrence of life-threatening ventricular arrhythmias in Chagas' disease versus non-Chagas' disease.” PubMed

Implementation Details Generative Model: Model learned using Matlab curve fitting tool Learning Accuracy = 2.13% Devices: Shimmer ECG Google donated Nexus Computation Energy Overhead = 0.8 mW Code Size = 5KB in RAM and 22 KB in ROM Application Size = 123 KB Demo Video: http://www.youtube.com/watch?v=NGBq-oyPhGI&feature=channel_video_title