Elke Naujokat

Sleep/wake detection based on cardiorespiratory signals and actigraphy

We investigated the potential of adding cardiac and respiratory activity information to actigraphy for sleep-wake staging. A dataset of 35 recordings with full polysomnography and actigraphy was used to assess the performance of an automated sleep/wake Bayesian classifier using electrocardiogram, inductance plethysmogram estimate of respiratory effort and actigraphy. The best performance was achieved with the linear discriminant model that provided an agreement of Cohens kappa=0.62 for one of the configurations of the classifier, corresponding to an accuracy of 86.8%, a sensitivity of 66.9% and a specificity of 93.1%. It shows that combining different vital signs for a home sleep-wake staging system could be a promising approach.

Sleep Monitoring Through a Textile Recording System

In this paper, we present a home device for the continuous monitoring of sleep and investigate its reliability regarding sleep evaluation. The system has been particularly designed for healthy people and for preventive purposes. It is not obtrusive and therefore can be used every night without impeding sleep in itself and without interfering with the normal way of life. The signal used for sleep evaluation is the HRV derived from the ECG recorded by means of a sheet and a pillow. Patients in a sleep lab and healthy subjects at home were monitored during sleep with the textile system, while also standard ECG and respiration were recorded. For the textile ECG sensor, coverage of the signal on a beat-to-beat basis ranged from 47,9 - 95,8% of the overall night for the healthy subjects, with a mean coverage of 81,8%. In the group of sleep laboratory patients, the mean coverage was lower - 64,4% - although even in this group the coverage of a single night ranged up to 98.4%. After frequency analysis, the spectral parameters used for sleep staging and derived at the same time from standard and textile ECG signals were compared. The trends along the night are very similar, indicating the possibility of using textile HRV for sleep evaluation.

TakeCare: A home-based sensor system for the management of cardiovascular risk factors Primary prevention by monitoring vital body signs, analysing the data and closing the loop by feedback, coaching, and motivation

Unobtrusive and easy-to-use sensor devices are used for monitoring the health condition of people interested in adopting a healthier lifestyle. The collected data from body sensors and input from questionnaires are analyzed allowing to derive improvement plans and recommendations. With the help of feedback, coaching and motivation a closed-loop system approach is realized optimally supporting people to reach their goals in daily life. The improved self-management has been successfully validated by people with sleep problems. They received tailored TakeCare systems for several weeks to be used in their own homes.