An rs-fMRI based neural marker for MRI-negative temporal lobe epilepsy with depression

Abstract

Objective: Depression is the most common comorbidity in epilepsy. Currently, the diagnosis of comorbid depression in epilepsy primarily relies on medical history and scales. However, this approach is highly subjective and heavily dependent on the physician's experience, and prone to missed or misdiagnosis. The primary objective of this study was to evaluate the effectiveness of network homogeneity (NH) measurements analyzed via support vector machine (SVM) in diagnosing MRI-negative temporal lobe epilepsy with depression (MRI-negative TLED).

Methods: The study included a total of 217 participants, comprising 90 healthy controls, 45 patients with MRI-negative temporal lobe epilepsy (MRI-negative TLE) and 82 patients with MRI-negative TLED. All subjects underwent resting-state fMRI scans for data collection. For analytical purposes, NH were computed and combined with SVM techniques for comprehensive data analysis.

Results: Compared to healthy control individuals, MRI-negative TLED patients demonstrated significantly increased NH values in the right mid-cingulum, right precuneus and right supramarginal, accompanied by decreased NH in the bilateral inferior temporal gyrus, left parahippocampal gyrus (PHG) and the right medial superior frontal gyrus (mSFG). Compared to MRI-negative TLE patients, MRI-negative TLED patients demonstrated significantly decreased NH values in the left parahippocampal gyrus (PHG) and the left mid temporalpole (MTP). SVM was used to differentiate patients with MRI-negative TLED from healthy control individuals based on rs-fMRI data, and the decreased NH in the left PHG showed highe diagnostic accuracy (71.56%).

Significance: According to the results, decreased NH values in the left PHG could serve as neuroimaging marker for MRI-negative TLED, offering objective guidance for its diagnosis.

Keywords: Depression; Network homogeneity; Resting-state fMRI; Support vector machine; Temporal lobe epilepsy.