Brain structural correlates of subjective sleepiness and insomnia symptoms in shift workers

• DOI: 10.3389/fnins.2024.1330695
• Publication Date: 2024-02-19T04:27:48Z
• Authors: Hyunwoo Jeong; Hyewon Yeo; Kyung Hwa Lee; Nambeom Kim; Jiyoon Shin; Min Cheol Seo; Sehyun Jeon; Yu Jin Lee; Seog Ju Kim
• Keywords: 0301 basic medicine; 03 medical and health sciences; neuroimaging; motor cortex; insomnia; brain imaging; Neurosciences. Biological psychiatry. Neuropsychiatry; shift worker; sleepiness; RC321-571; Neuroscience

BackgroundStudies on the brain structures of shift workers are limited; thus, this cross-sectional study aimed to compare the brain structures and the brain structural correlates of subjective sleepiness and insomnia symptoms between shift workers and non-shift workers.MethodsShift workers (n = 63) and non-shift workers (n = 58) completed questionnaires assessing subjective sleepiness and insomnia symptoms. Cortical thickness, cortical surface area, and subcortical volumes were measured by magnetic resonance imaging. The brain morphometric measures were compared between the groups, and interaction analyses using the brain morphometric measures as the dependent variable were performed to test the interactions between the study group and measures of sleep disturbance (i.e., subjective sleepiness and insomnia symptoms).ResultsNo differences in cortical thickness, cortical surface area, or subcortical volumes were detected between shift workers and non-shift workers. A single cluster in the left motor cortex showed a significant interaction between the study group and subjective sleepiness in the cortical surface area. The correlation between the left motor cortex surface area and the subjective sleepiness level was negative in shift workers and positive in non-shift workers. Significant interaction between the study group and insomnia symptoms was present for the left/right putamen volumes. The correlation between the left/right putamen volumes and insomnia symptom levels was positive in shift workers and negative in non-shift workers.ConclusionLeft motor cortex surface area and bilateral putamen volumes were unique structural correlates of subjective sleepiness and insomnia symptoms in shift workers, respectively.