Approximately 1 billion people worldwide experience some kind of chronic nasal congestion during sleep. Addressing this major health issue, IMEC (Leuven, Belgium) and research affiliate Holst Centre developed and clinically validated a miniaturized wireless sleep staging system, enabling early screening of abnormal sleep profiles outside of clinics.
IMEC’s lightweight, wearable system consists of a headband with three sensor nodes that measure two electroencephalogram (EEG) channels to monitor brain activity, two electrooculogram (EOG) channels to monitor eye activity, and an electromyogram (EMG) channel to monitor chin muscle activity. These five signals provide the required information for sleep staging according to the Rechtschaffen and Kales standard (the R&K standard classifies EEG-sleep recordings).
The sensor nodes integrate IMEC’s ultra-low-power biopotential read-out ASIC to amplify and filter the five different signals. Then those signals are wirelessly transmitted to the recording computer. No other wires from the head to body, or head to recording device, are needed.
The system was validated in the sleep laboratory at the University Hospital Center, Andre Vesale Hospital, Charleroi, Belgium against a commercially available reference system. Twelve volunteers enrolled in the study, and were monitored for a complete night using the wireless and reference systems, set up in parallel. Upon completion of the study, the signals were given to a sleep expert for blind scoring. Each subject wound up with two hypnograms, from which a series of sleep statistics were drawn.
See associated photo.