Study On The Mechanism Of RTMS In The Treatment Of Persistent Somatoform Pain Disorder Based On Brain Sensory Gating Theory

Objective:To explore the mechanism of repetitive Ttranscranial Magnetic Stimulation (rTMS) treating the persistent somatoform pain disorder (PSPD). Study the mechanism of brain sensory gating function in the pathogenesis of PSPD, then explore the mechanism and confirm the effectiveness of rTMS in the treatment of PSPD.Methods:1. Choose 30 cases of PSPD patients meeting the inclusion criteria and another 30 cases of healthy participants as the normal control group, test and analyze the P50 and PREP of both groups, then observe the differences.2. Thirty cases of PSPD patients were treated with 15 rTMS, evaluate and compare the VAS, P50 and PREP of rTMS groups before and after the treatment, and observe the differences of P50 and PREP of rTMS and normal control group after the treatment.Results:1. The function of brain sensory gating of PSPD patients were broken. Compared with the control group, the inhibit ratio of P50 of PSPD patients was higher (P<0.05); the amplitude of S1-P50 of PSPD patients was no significant change(P>0.05), while the amplitude of S2-P50 and the value of S2/S1 were significantly higher, and the S1-S2 value (the difference value of S1-P50 and S2-P50 amplitude) was lower(P<0.05). Excluding P6 wave, each one of PREP of drug group and drug combined rTMS group was shorter than the control group (P<0.05).2. Each wave of PREP had the negative correlation with S2/S1 and positive correlation with the amplitude of S1-P50 and difference value of S1-S2 amplitude(both P<0.05); and have no line correlation with the amplitude of S2-P50 (both P>0.05).3. After 3 weeks of treatment, the inhibit ratio of P50 of PSPD patients was reduced, the amplitude of S2-P50 and the S2/S1 value were also reduced(P<0.05), while the S1-S2 value was ascended but with no statistical significance (P>0.05). the latent period of P1、N1、 P2、N2、P4、N4、P5 waves of PSPD patients were significantly prolonged compared with the pre-treatment (P<0.05); the score of VAS were significant lower than the pre-treatment (P<0.05)4. Compared with healthy people, there were no significant difference with each waves of PREP and P50 of PSPD patients after treatment of rTMS (both P>0.05)Conclusion:1. The transmission speed of PSPD patients’nociceptive information was accelerated. PREP could response the mental reflect and information processing procedure of pain stimulation of PSPD patients, and may be applied to the evaluation of painful diseases.2. The broken function of brain sensory gating of PSPD patients was closely tied with the painful symptoms. So it may be the pathogenosis and etiotogy of PSPD.3. rTMS may through the nerve plastic effect to adjust the brain information processing, and then improve the sensory gating, cognitive process and pain symptoms of PSPD patients.