The Analysis Of Insular Lobe Function And Threshold Stimulation Intensities Based On The Stereo-electroencephalograph

Objective This study aimed to explore the function and analyze its electrophysiological characteristics of the insular lobe based on the stereoelectroencephalograph(SEEG).Methods To analyze the clinical and electrophysiological data of patients with refractory epilepsy.To study the localization of insular function by stimulating the stereotactic electrode contact with micro current,and analyze the results of each electrode contact corresponding to the insular sensory function characteristics and stimulation threshold.16 drug-refractory epilepsy patients implanted with SEEG electrodes were analyzed retrospectively.In total 34 electrodes(257 contacts)located in insular lobe.Micro current stimulation was performed every adjacent two contacts to get the sensory mapping and the stimulus threshold of the insular lobe.Results A total of 16 patients were enrolled in the study,and the 34 electrodes were located on the insula,with a total of 257 electrodes.Of all the 257 contacts,160 presented clinical symptoms(positive contacts),including somatic sensation,visceral sensation and aphasia and so on.The main clinical manifestations obtained by the stimulation were somatic sensation and visceral sensation abnormalities,etc.While somatosensory symptoms are located in the posterior insula,visceral sensory symptoms distribute relatively in the anterior insula.There were 149 contacts with sensory manifestations,of which 72 on the left side and 77 on the right.The threshold of somatosensory was 4.9 ± 2.9mA,and the threshold of visceral sensation was 6.0 ± 2.9mA.There was no significant difference between the two groups(P> 0.05).Values did not change either when the left insula sensory(6.2±3.1mA)compared to the right sensory(5.7±2.8mA)(P>0.05).The sensory function distributed almost parallel with the insular gyrus from the middle short gyrus to posterior long gurus,as laryngeal-lingual-facial(nasal and lips)-limb sensation,and the thresholds of the five insular gurus were 6.0 ± 3.1 mA,4.7 ± 1.5 mA,8.0 ± 2.9 mA,5.1 ± 2.4 mA and 4.5 ± 2.6 mA,respectively.The statistical analysis showed a statistically significant difference(P<0.01).Conclusions The symptoms of the insula present mainly according to the anatomy,but some of them are mixed.In addition,the manifestations of the insula are usually complex and individually.The sensitivity of somatic sensation and visceral sensation of the insula monitored by SEEG was similar as well as the left and right side.The sensory threshold and the sensory fan-shaped distribution play an important role in making insular symptoms and location more clearly for clinician.