Effect Of Brain Dysfunction In Temporal Lobe Epilepsy On Depression

Objective: To study the effect of epileptic brain dysfunction on depression by analysing the brain electrical activity along with brain structure and functional imaging data of patients with temporal lobe epilepsy(TLE) with depression and without depression which do facilitate the early clinical identification and prevention to us.Methods : A total of 36 patients with TLE,male 19, female 17, average age 33.9 ± 9.4 years old,were selected from March 2015 to December 2015 in the Department of epilepsy, General Hospital Affiliated to Tianjin Medical University and functional department of neurosurgery. According to Beck depression self rating scale(BDI) and Hamilton Depression Rating Scale(HAMD-17)score, we divided them into TLE with and without depression group which have 18 patients respectively. All patients underwent video-electroencephalogram( VEEG) and 3.0T Magnetic resonance imaging( MRI) and Resting-State functional Magnetic resonance imaging( RS-f MRI) and magnetic resonance spectroscopy(MRS) examination, and the normal control group underwent 3.0T MRI, RS-f MRI examination and then analyzing examination data of the two groups.Results :There were no significant differences in sex, age, seizure frequency of the two groups(P>0.05). There were statistically significant differences between the two groups of patients with epilepsy duration(P<0.05). There were statistically significant differences of interictal epileptiform discharges which is restrict to temporal lobe or spreading to other brain lobe including temporal lobe between the two groups in VEEG examination,and the advantage side of discharge either(P <0.05), we also found patients in depression group whose IEDs with left side advantage were more than non depression group. Single sample t test based on whole brain level from local consistency, low frequency amplitude and low frequency amplitude fraction(three kinds of RS-f MRI analysis methods) showed that the brain activation area of patients with temporal lobe epilepsy(TLE) was more than the normal control group and the brain activation area of the depression group was more than that of the non depression group, and the middle line structure of the depression group was activated apparently. Compared with the non-depression group by two sample t test showed that the more strong activate brain regions of depression group were including the frontal area, the precuneus,the anterior cingulate cortex and the hippocampus which are belong to default mode network and the midline stuctures of the thalamus and caudate nucleus;Compared with the normal control group by two sample t test showed that the more strong activate brain regions of non depression group were including orbital frontal gyrus, prefrontal cortex, superior temporal gyrus, inferior temporal gyrus knee hypodermal layer, anterior cingulate gyrus, cerebellum, occipital lobe and the genu of the corpus callosum.We found the NAA and NAA/Cho+Cr in the hippocampus of the ipsilateral dominant side of discharge were decreased in five of the eighteen patients in depression group in MRS and three of that five patients had hippocampal atrophy in MRI, while the non depression group had no obvious abnormalities like that.Conclusion:1. Depression of patients with TLE group was longer than that non depression group of patients with TLE group. Compared with two group,the advantage side of temporal lobe IEDs showed that the left(dominant hemisphere) involved more in depression group.Compared the range of IEDs discharge, patients of depression group wider than non depression group.All that showed the patients who had a wide range of IEDs and involved the dominant side of the brain were more vulnerable to developed depression.2. Midline structures and functional impairment of DMN play an important role in the formation of depression in patients with TLE.3. Brain areas involved in TLE network: regard the limbic system as the center of enhanced activation brain regions including the midbrain, subcortical cortex, anterior cingulate gyrus and genu of corpus callosum; neocortical brain regions including orbitofrontal gyrus, prefrontal cortex, superior temporal gyrus and inferior temporal gyrus and other brain regions. Temporal lobe epileptic discharge of brain areas is not limited in the hippocampus and the amygdala, which impact on the frontal lobe of other brain regions and therefore the functions were impaired, it helped us to understand and further research in patients with TLEwho had advanced neural function activities impared included damage to the emotional and cognitive activities and provide a new research direction.4. The loss of integrity of hippocampal structure and the hippocampus of the epileptogenic focus hyperexcitability which effect on the the functions of limbic system and neocortical, it may be the Pathophysiology of TLE associated with depression. Hippocampal atrophy may be one of the pathophysiological mechanisms of TLE with depression. TLE and depression may have a common neuroanatomical basis and they interrelated to each other in the disease process.