Authors: Cüneyt Yücelbaş Şule Yücelbaş Seral Özşen Gülay Tezel Serkan Küççüktürk Şebnem Yosunkaya
Publish Date: 2016/07/12
Volume: 29, Issue: 8, Pages: 17-33
Abstract
Sleep staging is a significant process to diagnose sleep disorders Like other stages several parameters are required for the determination of NREM2 stage Sleep spindles SSs are among them In this study a methodology was presented to automatically determine starting and ending positions of SSs To accomplish this shorttime Fourier transform–artificial neural networks STFT–ANN empirical mode decomposition EMD and discrete wavelet transform DWT methods were used Two considerable methods which were determination envelope and thresholding of the decomposed signals by EMD and DWT were also presented in this study A database from the EEG signals of nine healthy subjects—which consisted of 100 epochs including 172 SSs in total—was prepared According to the test results the highest sensitivity rate was obtained as 100 and 9942 for EMD and DWT methods However the sensitivity rate for the STFT–ANN method was recorded as 5593 The results indicated that the EMD method could be confidently used in the automatic determination of SSs Thanks to this study the sleep experts will be able to reliably find out the epochs with SSs and also know the places of SSs in these epochs automatically Another important point of the study was that the sleep staging process—tiring timeconsuming and high fallibility for the experts—could be performed in less time and at higher accuracy ratesAll procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national Noninvasive Clinical Research Medical Ethics Review Board and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards
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