In the clinical sleep medicine measurements at the patient are carried out mainly at sleep laboratories where many body functions are included at the same time – with numerous electrodes the electroencephalogram (EEG: brain activity), the electrooculogram (EOG: eye movements) and for the most part the electromyogram (EMG: muscle contractions) as well as the breathing are recorded. The result of this is a sleep disturbed by the measuring construction at least during the first night at the laboratory. Aim of the sleep monitoring project is the establishment of a method for the measurment of the autonomous nervous system in the sleep medicine as well as the development of a mobile sleep monitor which permits a judgement of the sleep quality from few parameters and thus is stressless for the patient. For the implementation of the methodology, which is based on the analysis of the heart rate variability (HRV), high-resolution ECG notes and ballistocardiogram were carried out by means of newly developed sensors as well as EEG reference measurments. The gained cognitions make clear that it is difficult to clearly categorize a phenomenon as complex as the sleep with scientific methods. With regard to the tratitional sleep classification limits are set to a simple measuring system. A particularly important project result is, however, the development of methods for the integral sleep quality assessment from the analysis of the heart frequency variability which can provide new impulses and information to the sleep research at the patient′s bedside. The methods worked out are modified and developed further in an extensive follow-up project for the characterization of certain states of activation and consciousness.
Conventional sensor technology of sleep research.
Sensors for detection of sleep stages by parameters of heart rate variability.
Sensor technology for contactless measurement of heart rate during sleep.