A One-Sensor System for Home Diagnosis and Therapy of Snoring and Sleep Apnea
Master thesis
Permanent lenke
http://hdl.handle.net/11250/2368993Utgivelsesdato
2007Metadata
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Sammendrag
The average sleeping time suffers from a more and more stressful life, and is now close to the limit of what the human being can bear. Therefore, a good quality sleep is more important than ever. At the same time, the problem of snoring is increasing as a result of overweight and a longer life, two important factors which contribute to the risk of snoring - nowadays about 50 % of those over 40 years of age are habitual snorers. Although the problem is often made fun of, those affected do not find it very funny. The bed partners suffer from daytime sleepiness, and the snorer himself is at risk of having related medical conditions like obstructive sleep apnea, which also lead to daytime sleepiness. Even though the problem is widely known, many hesitate to adress the problem. And even so, the sleep laboratories have long waiting lines, where patients have to do an expensive over-night study. A reliable screening device to use at home would shorten the waiting line and even give an adequate diagnose in many cases, without the need of an over-night study. This would also be more comfortable to the snorer, since the test could then be done in his natural sleeping environment. That is why this thesis has as goal to create a simple, affordable device to help those affected by the problem of snoring. In the previous bachelor thesis, an accelerometer was found usable for snoring detection in splint worn on the teeth. By utilizing the whole capacity of a accelerometer, all measurements needed for a snoring and even sleep apnea can be done. In this thesis it is demonstrated that a low-power miniaturized three-axis accelerometer is able to measure sleeping position, breathing movements, heart rate and snoring as well. The accelerometer detects the vibrations from snoring as changes in acceleration, since the soft tissues in the mouth were snoring arise are directly connected with the teeth, where the accelerometer is firmly mounted inside a splint. In a similar way, the head movement from breathing and also the force from the pulse was measured by applying the right amplification and filtering. The static sleeping position was measured as the gravity influence on the two axes perpendicular to the horizontal sleeping plane. A questionnaire was made to get a better understanding of how much people know about these problems and how they would like to address the problem if they are affected by it. The results revealed that the top motivation for wanting a snoring diagnosis is the fear of obstructive sleep apnea, while consideration to their bed partner was not so important. Hence, we have to include the possibility of detection OSA with the device. The questionnaire also revealed that the splint is choice number one for an eventual bed partner of the participants, but for participants themselves, a headband with sensor was preferred over the splint. A headband prototype was therefore built as an alternative system to the splint. The accelerometer placed in a headband will detect the vibrations and movement identical to the splint, since they both measure the movement of and vibrations on the skull and the teeth respectively, which are both directly connected with the tissues that vibrate when snoring. The system created can be used as a diagnostic splint or headband, or built into a so-called mandibular retaining appliance, which is a popular device for mechanical therapy of snoring. The integration of our system could be used in order to optimize this treatment, and reduce the follow-ups. About 50 % have the problem of obstructive sleep apnea and snoring only when sleeping on their back, which according to a sleep expert and studies can be solved by some sort of stimulus telling the person "now I must change position". That is why a vibration motor was implemented as therapy. The vibration strength can be adjusted with the software. By using only one accelerometer as sensor the system can be made cheaper and smaller than other devices on the market, and without disturbing cables. In addition, it is small and low-power consuming, so that it can be used in closed system as the splint.