Sleep Quality Differences According to a Statistical Continuous Sleep Model

Abstract

This paper presents sleep quality differences between good and bad sleepers measured with a statistical continuous sleep model according to the Self-Rating Questionnaire for Sleep and Awakening Quality (SSA). Our main goal is to describe sleep continuous traces that take into account the sleep stage probability with a temporal resolution of 3 s, instead of the Rechtschaffen and Kales (R and K) resolution, which is 30 s. We adopt in our study the probability of being in stages W, S1, S2, S3, S4, and REM. The system uses only one electroencephalographic (EEG) channel. In order to achieve this goal we start by applying a hidden Markov model, in which the hidden states are associated with the sleep stages. These are probabilistic models that constitute the basis for the estimation of the sleep stage probabilities. The features that feed our model are based on the application of a discrete cosine transform to a vector of logarithmic energies at the output of a set of linearly spaced filters. In order to find differences between groups of sleepers, we define some measures based on the probabilistic traces. The experiments are performed over 24 recordings from the SIESTA database. The results show that our system performs well in finding differences in the presence of the Wake and S4 sleep stages for each group.