# Altered EEG microstate associated with anxiety and somatization symptoms in major depressive disorder

## TL;DR

This study finds that brain activity patterns measured by EEG differ in people with depression and are linked to anxiety and physical symptoms.

## Contribution

The study identifies specific EEG microstate dynamics in MDD patients associated with anxiety and somatization symptoms.

## Key findings

- MDD patients showed increased duration and coverage of microstate C and decreased occurrence of microstate B.
- Transition probabilities between microstates C and D were altered in MDD patients.
- Microstate B occurrence correlated with anxiety and somatization symptoms in MDD.

## Abstract

To examine abnormalities in EEG microstate dynamics in patients with major depressive disorder (MDD) and to explore their associations with anxiety and somatization symptoms.

We enrolled 30 patients with MDD and 40 healthy controls. Resting-state EEG was recorded and analyzed using microstate segmentation (classes A–D). Temporal parameters (mean duration, occurrence, time coverage, and transition probabilities) were compared between groups, and correlations with clinical symptoms (HAMD, HAMA, MADRS) were examined.

Compared with controls, patients with MDD exhibited a significantly longer duration, higher occurrence, and greater time coverage of microstate C, while microstate B showed reduced occurrence and coverage. Transition probability analyses revealed fewer transitions from A to B, A to D, B to A, B to D, and D to A, and more transitions between C and D. Symptom correlations indicated that microstate B occurrence was positively associated with HAMD anxiety/somatization scores, while transitions from C to D and from D to C were negatively correlated with anxiety/somatization scores.

MDD is characterized by alterations in microstate B and C dynamics and disrupted transitions between C and D, some of which relate to symptom dimensions, suggesting that EEG microstate features may serve as potential neurophysiological markers in major depressive disorder.