Regional homogeneity changes in patients with primary insomnia

Purpose: The study aimed to explore the regional spontaneous activity changes in primary insomnia (PI) patients.

Materials and methods: Based on the resting-state fMRI datasets acquired from 59 PI patients and 47 healthy controls, a two-sample t-test was performed on individual normalized regional homogeneity (ReHo) maps. Relationships between abnormal ReHo values and the Pittsburgh Sleep Quality Index (PSQI), the self-rating anxiety scale (SAS) and the self-rating depression scale (SDS) were investigated with Pearson correlation analysis.

Results: In PI patients, we found increased ReHo in the left insula, right anterior cingulate gyrus, bilateral precentral gyrus and left cuneus, as well as decreased ReHo in the right middle cingulate cortex and left fusiform (p < 0.05, AlphaSim-corrected). We also found a significant positive correlation between increased ReHo in the left insula and SAS scores, decreased ReHo in the right middle cingulated cortex and SDS, SAS scores as well as a negative correlation between increased ReHo in the right precentral gyrus and SDS scores (p < 0.05).

Conclusions: Our study found abnormal spontaneous activities in multiple brain regions, especially in emotion-related areas in PI patients. Alterative activities in these regions might contribute to an understanding the intrinsic functional architecture of insomnia and its clinical features.

Key points: • Regional spontaneous activity changes were detected in PI patients. • Decreased or increased ReHo of some regions was identified in PI patients. • Significant correlations between mean ReHo and SDS scores were found.