Nocturnal Sleep Quality and Quantity Analysis with Ballistocardiography

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Sähkötekniikan korkeakoulu | Master's thesis
Degree programme
EST - Elektroniikka ja sähkötekniikka (TS2005)
57 + 8
The aim of this thesis was to evaluate usability and performance of a ballistocardiography (BCG) based method for qualitative and quantitative analysis of sleep. The method was validated and the basis for sleep stage detection was presented. Sleep problems are one of the most common medical complaints today. Polysomnography (PSG) as the current standard for sleep analysis is expensive, intrusive and complicated. Thus, finding a reliable and unobtrusive method for longer-term home use is important. BCG based methods have shown potential in sleep analysis recently. In this thesis, the BCG method was validated in a clinical test on 20 subjects. PSG was used as the reference. A software was developed to process the recordings and analyze the results. Heart rate (HR), heart rate variability (HRV), respiratory rate (RR), respiratory rate variability (RRV), respiratory depth (Rdepth) and movement were utilized for sleep stage detection. Finally, the BCG product was compared with other commercial sleep analysis focused BCG products. In validation, the BCG parameter accuracy was presented as the mean error from PSG with 95% confidence interval. The errors were -0.1 ± 4.4 beats per minute for HR, -0.9 ± 14.7 ms for high frequency (HF) HRV, -3.0 ± 29.9 ms for low frequency (LF) HRV, 0.3 ± 4.5 breaths per minute for RR and -40 ± 424 ms for RRV. Correlation coefficient was 0.97 for HR, 0.67 for HF HRV, 0.71 for LF HRV, 0.54 for RR and 0.49 for RRV respectively. HR, RRV and Rdepth were typically at an increased level in REM sleep and wakefulness and decreased in deep sleep. RRV was at its highest during wakefulness. HRV was at a decreased level in REM and wakefulness and increased in deep sleep. Movement was higher during wakefulness than in sleep. Murata BCG Sensor Node had advantages in the accuracy of measurements and usability compared to other BCG based sleep analysis products.
Sepponen, Raimo
Thesis advisor
Meriheinä, Ulf
ballistocardiography, polysomnography, sleep quality, respiration, heart rate variability
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