An Exploration of Self-Reported Sleep Inertia Symptoms Using Network Analysis

Abstract

Purpose

Sleep inertia (SI) is the transitional state accompanied by compromised cognitive and physical performance and sleepiness. Network analysis offers a potential new framework to conceptualize a complex network of symptom–symptom interactions, and the network structure is analyzed to reveal the core characteristics. However, no previous study examined the network structure of SI symptoms. Thus, this study aimed to elucidate characteristics and compare sex differences of SI symptom networks in the general population.

Materials and Methods

A total of 1491 participants from China were recruited from 30 May to 17 June, 2021. SI symptoms were assessed by using the Sleep Inertia Questionnaire (SIQ). The network structures were estimated and compared using network analytic methods in the R version 4.1.1.

Results

Centrality properties analysis of the expected influence suggested that symptoms of “Feel sleepy”, “Groggy, fuzzy or hazy mind”, and “Dread starting your day” exerted greatest influences. The weighted adjacency matrix revealed that the “Dread starting your day” and “Anxious about the upcoming day” edge showed the strongest connection (edge weight value = 0.70). The network comparison test found no significant difference in network global strength (p=0.928), distribution of edge weights (p=0.194) and individual edge weights (all p values >0.05 after Holm–Bonferroni corrections) between males and females.

Conclusion

Symptoms of “Feel sleepy”, “Groggy, fuzzy or hazy mind”, and “Dread starting your day” were central in the SI symptom network. Intervention, such as the artificial dawn and change in body temperature, for symptoms of “Feel sleepy”, “Groggy, fuzzy or hazy mind”, and “Dread starting your day” might be crucial to hasten the dissipation of SI in the general population who may need to perform tasks upon waking.

Keywords:

• sleep inertia
• Sleep Inertia Questionnaire
• network analysis
• general population

Abbreviations

SI, sleep inertia; SIQ, Sleep Inertia Questionnaire; SD, standard deviation; EBICglasso, Extended Bayesian Information Criterion graphical least absolute shrinkage and selection operator; SPL, shortest path length; Cis, confidence intervals; CS-C, correlation stability coefficient; NCT, Network Comparison Test.

Ethics Approval

This study protocol was approved by the human research ethics committee of South China Normal University (Approval No.: SCNU-PSY-2021-247).

Acknowledgments

The work was supported by National Natural Science Foundation of China (Grant No. 31871129, 31671165). The authors would like to thank all participants, and schools for their supports.

Disclosure

The authors declare no conflicts of interest in this work.