Scientists develop mobile sleep lab for home use

Feb 22 2009

Poor sleep can be attributed to many causes, including shift work, stress, snoring or even sleep apnea - a disorder in which the sleeper temporarily stops breathing.

Until now, only a sleep laboratory could determine whether a patient is suffering from sleep apnea or related sleep disturbances. In a traditional sleep laboratory, the patient is observed while sleeping for at least one night, connected to cables and observed by a large number of measuring instruments and cameras. Researchers at the Fraunhofer Institute for Integrated Circuits IIS in Erlangen have now developed a mobile sleep lab for home use.

SomnoSENS consists of a small box that is worn attached to the body during sleep and observes vital functions. Four adhesive electrode pads are used to record an electrocardiogram (ECG), while a finger clip measures the patient's blood oxygen level and pulse rate. A nasal clip and expandable belts around the upper torso monitor breathing, and a movement sensor in the device identifies the patient's body position and registers how much he or she moves. "The device is attached to the body during sleep and does not hinder sleep comfort due to its miniature size," Herbert Siegert from IIS assures. "SomnoSENS records and stores the data, and transmits them to the base station via a Bluetooth wireless interface. The physician can later evaluate the stored information to make an evidence-based diagnosis."

Patients with cardiovascular problems are often fearful of suffering another heart attack or developing other heart complications. They cannot visit the doctor daily to gain assurance about their condition. The SYSVital telemonitoring device devised by the Fraunhofer Institute for Photonic Microsystems IPMS in Dresden offers assistance to patients with heart problems.

Heart patients simply wear a small, lightweight device on their body. It records heartbeats via a 3-channel ECG, identifying minimum and maximum heart rates as well as arterial fibrillation. At the same time, the device records movement. A physician can evaluate, for instance, the heart rate in connection with physical effort, thus simplifying the diagnosis. The system also permits recovery time to be determined after physical exercise. The data are transferred via a home gateway to an Internet portal where the physician can access the information remotely. A range of optional components can be added to the system to measure other vital data such as blood pressure, weight or blood sugar level.

Experts recommend physical exercise in order to prevent illness. But how many people manage to exercise regularly? Perhaps it might be enough to stay fit by walking to the subway, climbing the stairs to the third floor or doing household chores? A new device can determine how active we actually are. "ActiSENS measures a person's physical activity throughout the day," Herbert Siegert of the Fraunhofer Institute for Integrated Circuits IIS in Erlangen explains. The user merely needs to attach a small box containing movement sensors to their belt. The device translates activities into points to provide objective feedback regarding the user's personal level of physical exercise. Points are awarded on the basis of the type of activity: Climbing stairs earns more points than jogging, jogging more than walking, and so on. Zero points are awarded for driving or taking the elevator.

During the day, the current score can be displayed on the device at any time. In the evening, the accumulated data for the day can be transferred to a PC via Bluetooth and analyzed in greater depth according to previously selected parameters. The data can also be forwarded to a physician for evaluation. In this way it can be determined, for example, whether a patient's prescribed physical therapy is producing the desired results.