Ambient Intelligence in the Bedroom

Ways To Monitor Health

Since we spent almost a third of our lives in bed, it presents an enormous opportunity for general health monitoring. During the past decade, numerous methods and techniques have been developed to record vital body parameters such as respiratory and cardiac activity from within or around our bed. Some methods directly measure electrical activity of the heart, while others focus on the mechanical activity of both heart and lungs. The main idea is however to perform all measurements off-body, e.g. without attaching sensors directly to the skin. This will make sure that subjects are not disturbed before and during their sleep, both physically and mentally. Physical disturbance can occur due to skin irritation on places where sensors were attached, or the presence of wires connecting the sensors to a registration or transmitting device. Mental disturbance on the other hand can be due to the person being aware that he or she is being measured, or to the nuisance of attaching the sensors before being able to go to sleep.

Once heart and breathing rate are acquired, heart and breathing rate variability analysis (i.e. temporal changes in heart and breathing rate analysed in both time and frequency domain (Cardiology Task Force, 1996)) can lead to information regarding cardiac health, stress and sleep quality. The latter two are based on research that links the variability within heart and breathing rate to the sympathetic and parasympathetic variations within the autonomic nervous system (Somers, Dyken, Mark, & Abboud, 1993). Based on this link, differences in stress level of a person can be perceived (Hall et al., 2004), his/her sleep pattern can be analysed (Willemen et al., 2013) and possible sleep disorders can be detected (Stein & Pu, 2012).

In this subchapter on health monitoring, we will first discuss how respiratory and cardiac activity can be registered off-body from within or around our bed, after which we will go into more detail on the relevant information that can be extracted from these signals and how this information can be used.