title: A multi-sensor monitoring system of human physiology and daily activities.
abstract: OBJECTIVE
  To present the design and pilot test results of a continuous multi-sensor monitoring system of real-world physiological conditions and daily life (activities, travel, exercise, and food consumption), culminating in a Web-based graphical decision-support interface.
  
  
  METHODS
  The system includes a set of wearable sensors wirelessly connected to a "smartphone" with a continuously running software application that compresses and transmits the data to a central server. Sensors include a Global Positioning System (GPS) receiver, electrocardiogram (ECG), three-axis accelerometer, and continuous blood glucose monitor. A food/medicine diary and prompted recall activity diary were also used. The pilot test involved 40 type 2 diabetic patients monitored over a 72-h period.
  
  
  RESULTS
  All but three subjects were successfully monitored for the full study period. Smartphones proved to be an effective hub for managing multiple streams of data but required attention to data compression and battery consumption issues. ECG, accelerometer, and blood glucose devices performed adequately as long as subjects wore them. GPS tracking for a full day was feasible, although significant efforts are needed to impute missing data. Activity detection algorithms were successful in identifying activities and trip modes but could benefit by incorporating accelerometer data. The prompted recall diary was an effective tool for augmenting algorithm results, although subjects reported some difficulties with it. The food and medicine diary was completed fully, although end times and medicine dosages were occasionally missing.
  
  
  CONCLUSIONS
  The unique combination of sensors holds promise for increasing accuracy and reducing burden associated with collecting individual-level activity and physiological data under real-world conditions, but significant data processing issues remain. Such data will provide new opportunities to explore the impacts of human geography and daily lifestyle on health at a fine spatial/temporal scale.
authors.affiliation: Department of Geography & Environmental Studies, Wilfrid Laurier University, Waterloo, Ontario, Canada. sdoherty@wlu.ca
authors.forename: Sean T
authors.initials: ST
authors.lastname: Doherty
authors.forename: Paul
authors.initials: P
authors.lastname: Oh
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D040421:Cell Phone; D003924:Diabetes Mellitus, Type 2 / Q000628:therapy*; D015716:Electrocardiography, Ambulatory / Q000379:methods; D004867:Equipment Design; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation*; D008991:Monitoring, Physiologic / Q000295:instrumentation; D009864:Ontario; D010865:Pilot Projects; D012984:Software; D017216:Telemedicine / Q000379:methods*; D014584:User-Computer Interface
chemical_list: D001786:Blood Glucose