Background: Recently, several functional neuroimaging studies have been conducted in patients with persistent insomnia disorder, but these studies have yielded diverse findings. We aimed to identify convergence in function across the heterogeneity of patients, modalities, and methods for insomnia disorder by performing a quantitative coordinate-based meta-analysis.
Materials and methods: We performed a quantitative, voxel-wise meta-analysis of resting-state fMRI studies using seed-based d mapping to find convergence of functional alterations in persistent insomnia disorder.
Results: We included 28 studies comprising 287 peak foci involving 951 patients with insomnia disorder and 884 healthy controls. Patients with persistent insomnia disorder showed that increased activity was more frequently reported in right parahippocampal gyrus (p < 0.001) and left median cingulate/paracingulate gyri (p < 0.001); while decreased activity was more frequently reported in right cerebellum (p < 0.001) and left superior frontal gyrus/medial orbital (p < 0.001).
Conclusion: The altered functional networks in patients with persistent insomnia disorder converge in median cingulate/paracingulate gyri and right parahippocampal gyrus with increased activity, and cerebellum and superior frontal gyrus/medial orbital with reduced activity. As a potential target in future, the identification of these altered or unbalanced networks is very important because they may be noninvasively rebalanced to sleep homeostasis by noninvasive brain stimulation methods.
Keywords: Insomnia disorder; Resting-state functional magnetic resonance; Seed-based d mapping; fMRI.