Electroencephalogram microstate analysis in temporal lobe epilepsy: A comparative study with and without anxiety

Anxiety is a prevalent psychiatric comorbidity in temporal lobe epilepsy (TLE), however, limited attention has been given to the dynamic characteristics of TLE coexisting with anxiety.The aim of this study was to examine abnormal resting-state Electroencephalography (EEG) microstate dynamics in TLE patients with anxiety disorders compared with TLE patients without anxiety disorders and healthy controls.

Ninety participants in this study: 30 healthy controls (HC), 30 TLE patients with anxiety (PAS), and 30 TLE patients without anxiety (nPAS). The dynamic changes in the entire brain were detected using a 21-channel EEG for microstate analysis. This study comprehensively compared the mean duration, frequency of occurrence, time coverage, and transition probability of each microstate(A, B, C, D) among the three groups. Rigorous statistical methods were employed to ensure the robustness and validity of the research findings.

The results of EEG microstate analysis revealed that the occurrence frequency and time coverage of microstate B (visual network) in the PAS were significantly reduced compared to the nPAS. Compared to HC and nPAS groups, patients with PAS exhibited alterations in the probability of EEG microstate transitions: an increase in transitions from the microstate C (salience network) to the microstate A (auditory network), a decrease in transitions from the dorsal microstate C (salience network) and microstate D (attention network) to the microstate B (visual network). These changes suggest heightened overall network alertness, impaired attention-visual pathway function, and decreased stability of the attention network.

Our research reveals that anxiety disorders in individuals with temporal lobe epilepsy are characterized by heightened alertness, impaired attention-visual integration, and instability of the dorsal attention network. This highlights the significant impact of anxiety on brain network remodeling and cognitive control deficits. Changes in EEG microstate dynamics may serve as a novel biomarker for psychiatric complications associated with epilepsy.