A Review of Approaches for Sleep Quality Analysis

Abstract

Sleep quality is directly related to overall wellness and can reveal symptoms of several diseases. However, the term ''sleep quality'' still lacks a definitional consensus and is commonly assessed in sleep labs with polysomnography, comprising high costs, or through sleep questionnaires, a highly subjective technique. Multiple methods have been proposed to address the estimation of sleep quality, and devices were developed to conduct the examination in the subject's home. The objective of this paper is to analyze the methods and the devices presented in the literature, assessing the development of objective markers that could lead to an improvement of the subjective sleep experience understanding, leading to developments in the treatment of sleep quality deficits. A systematic review was conducted, selecting research articles published from 2000 to 2018, and two research questions were formulated, specifically, ''what methods for sleep quality assessment have been developed'' and ''what kind of measures are employed by the devices that have been developed to estimate sleep quality.'' The research trend for the assessment of sleep quality is based on the sleep macrostructure, and it was verified that despite the convenience and considerable popularity among the consumers of home health monitoring of devices, such as actigraphs, the validity of these tools regarding the estimation of sleep quality still needs to be systematically examined. A detailed resume of the key findings and the identified challenges are presented, ascertaining the main gaps in the current state of the art. INDEX TERMS Sleep quality analysis, monitoring devices, home detection.

Effect of an Inflatable Air Mattress with Variable Rigidity on Sleep Quality

“…Through the EEG analysis, sleep indices from all sleep stages (Wake, REM, Light and Deep) could be estimated. Mendonca et al reported that the higher the lengths of REM sleep, and Deep stages, and RNR were, the higher sleep quality was, while the lower SSI yielded the better one [ 55 ]. In our experiment, REM period under the customized SH condition was significantly longer than that under the uncustomized A condition, as shown in Figure 8 a, which was tested using wilcoxon signed-rank test ( p < 0.05).…”

“…Subjective sleep assessment was conducted through questionnaires. The length information of each sleep stage was obtained from a hypnogram, as an objective sleep evaluation, where the duration of REM and Deep stages (slow wave sleep, SWS) are the length information of the stages, conventionally used to measure the sleep quality [ 55 ]. REM stage maintains the necessary levels of central nervous system activities, promotes a recovery with providing periodic stimulation to the brain [ 56 ] and preserves emotional memory sources selectively [ 57 ].…”

“…Additionally, RNR (REM to Non-REM ratio) and SSI (Stage Shift index) were calculated as sleep indices corresponding to the sleep quality. Mendonca et al reported that the higher RNR and the lower SSI result in the improvement of sleep quality [ 55 ]. RNR is an index representing the ratio of the duration of the REM stage to that of the non-REM stage, as shown in Equation ( 1 ).…”

A Portable Wireless Device for Cyclic Alternating Pattern Estimation from an EEG Monopolar Derivation

“…The quality of sleep can be estimated by PSG-based sleep quality measures [ 11 ]. CAP is considered a sleep instability metric since a disturbance in sleep generates distinguishing alterations in neural electrical activity that, usually, produce an A phase [ 12 ].…”

A method of extracting latent semantic components from noisy categorical time-series data applied to human sleep stage data

“…Sleep is directly related to overall wellness and has been actively studied by medical scientists or medical engineers, using multifarious methods [1], [2]. However, in such methods, the categorization of sleep state into stages has been basic [1], and it is recognized that the dynamics of sleep stage transition is important [3].…”