Optimizing sleep staging on multimodal time series: Leveraging borderline synthetic minority oversampling technique and supervised convolutional contrastive learning

Xinyu Huang; Franziska Schmelter; Muhammad Tausif Irshad; Artur Piet; Muhammad Adeel Nisar; Christian Sina; Marcin Grzegorzek

doi:10.1016/j.compbiomed.2023.107501

Optimizing sleep staging on multimodal time series: Leveraging borderline synthetic minority oversampling technique and supervised convolutional contrastive learning

Comput Biol Med. 2023 Sep 18:166:107501. doi: 10.1016/j.compbiomed.2023.107501. Online ahead of print.

Authors

Xinyu Huang¹, Franziska Schmelter², Muhammad Tausif Irshad³, Artur Piet⁴, Muhammad Adeel Nisar⁵, Christian Sina⁶, Marcin Grzegorzek⁷

Affiliations

¹ Institute of Medical Informatics, University of Lübeck, Germany. Electronic address: x.huang@uni-luebeck.de.
² Institute of Nutritional Medicine, University of Lübeck and University Medical Center Schleswig-Holstein, Lübeck, Germany. Electronic address: Franziska.Schmelter@uksh.de.
³ Institute of Medical Informatics, University of Lübeck, Germany. Electronic address: m.irshad@uni-luebeck.de.
⁴ Institute of Medical Informatics, University of Lübeck, Germany. Electronic address: ar.piet@uni-luebeck.de.
⁵ Department of IT, University of the Punjab, Lahore, Pakistan. Electronic address: adeel.nisar@pucit.edu.pk.
⁶ Institute of Nutritional Medicine, University of Lübeck and University Medical Center Schleswig-Holstein, Lübeck, Germany; Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering (IMTE), Lübeck, Germany. Electronic address: Christian.Sina@uksh.de.
⁷ Institute of Medical Informatics, University of Lübeck, Germany; Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering (IMTE), Lübeck, Germany. Electronic address: marcin.grzegorzek@uni-luebeck.de.

PMID: 37742416
DOI: 10.1016/j.compbiomed.2023.107501

Abstract

Sleep is an important research area in nutritional medicine that plays a crucial role in human physical and mental health restoration. It can influence diet, metabolism, and hormone regulation, which can affect overall health and well-being. As an essential tool in the sleep study, the sleep stage classification provides a parsing of sleep architecture and a comprehensive understanding of sleep patterns to identify sleep disorders and facilitate the formulation of targeted sleep interventions. However, the class imbalance issue is typically salient in sleep datasets, which severely affects classification performances. To address this issue and to extract optimal multimodal features of EEG, EOG, and EMG that can improve the accuracy of sleep stage classification, a Borderline Synthetic Minority Oversampling Technique (B-SMOTE)-Based Supervised Convolutional Contrastive Learning (BST-SCCL) is proposed, which can avoid the risk of data mismatch between various sleep knowledge domains (varying health conditions and annotation rules) and strengthening learning characteristics of the N1 stage from the pair-wise segments comparison strategy. The lightweight residual network architecture with a novel truncated cross-entropy loss function is designed to accommodate multimodal time series and boost the training speed and performance stability. The proposed model has been validated on four well-known public sleep datasets (Sleep-EDF-20, Sleep-EDF-78, ISRUC-1, and ISRUC-3) and its superior performance (overall accuracy of 91.31-92.34%, MF1 of 88.21-90.08%, and Cohen's Kappa coefficient k of 0.87-0.89) has further demonstrated its effectiveness. It shows the great potential of contrastive learning for cross-domain knowledge interaction in precision medicine.

Keywords: B-SMOTE; Biosignal processing; Cross-domain adaption; Multimodal polysomnography; Residual network; Sleep stage classification; Supervised contrastive learning; Truncated cross-entropy.