Abstract:Objective To investigate the altered functional connectivity of the default mode network in patients with MRI-negative
temporal lobe epilepsy using resting-state functional MRI based independent component analysis method. Methods In this study,
a total of 16 patients with left temporal lobe epilepsy and 26 patients with left temporal lobe epilepsy with hippocampal sclerosis
and 24 healthy controls were included. The Montreal cognitive assessment (MoCA) was used to perform cognitive testing on the
three groups. A resting-state functional MRI scan was first performed, and the data were pre-processed using DPABI software
based on MATLAB 2012b platform. Then the SPM12 software and independent component analysis method were used for default
mode network analysis and three groups of different brain regions were extracted. Single-sample t test and analysis of variance
were used to compare the changes of functional connectivity in related brain regions and the differences between the three
groups. Results MRI-negative epilepsy patients with or without hippocampal sclerosis had lower MoCA score than the control
group. The MRI-negative temporal lobe epilepsy group had decreased functional connectivity in the left precuneus, right precuneus,
and posterior cingulate gyrus (t=-3.1527, P<0.05, AlpaSim correction). Bilateral precuneus/posterior cingulate gyrus connectivity
was reduced in the group with hippocampal sclerosis (t=-3.6605, P<0.05, AlpaSim correction). Compared with the MRI-negative
temporal lobe epilepsy group, the group with hippocampal sclerosis had reduced connectivity in the left prefrontal lobe and anterior
cingulate gyrus (t=-3.4775, P<0.05, AlpaSim correction). Conclusion Patients with MRI-negative epilepsy with or without
hippocampal sclerosis have mild cognitive dysfunction, and MRI-TLE patients have a higher degree of impairment in the default
mode network than patients with hippocampal sclerosis. MRI-negative temporal lobe epilepsy brain functional abnormalities can
explore the intrinsic pathophysiological mechanisms of the disease, functional changes in the brain caused by epileptic discharges
and the process of micro structural changes, which can help clinical understanding of the changes in brain areas caused by seizures
and guide the use of medication and rehabilitation treatment.