Intracortical Inhibition In Schizophrenia:a Study Of Biomaker And Course Comparetion

Objective:At present,the diagnosis of schizophrenia depends on symptomatology and lacks specific biomarkers that are convenient and easy to measure.Through measurement and comparison of intracortical inhibition in schizophrenic different phase,we could know whether it could be the maker of schizophrenia and how they have changed in course.Methods:This study inclouds 76 cases,consisting of 19 first-episode schizophrenics,20 remission schizophrenics,17 shizophrenic first degree relative and 20 normal healthy people whose age and sex matchs others.Theirs diagnosis meets the DSM-IV criteria.We use TMS-EMG to evoke testers' intracortical inhibition and record it.Use 80%resting motor threshold(RMT)as the conditioning stimulus(CS)and 120%RMT as the testing stimulus(TS)to evoke short-interval cortical inhibition(SICI)while it shouled be limited at 2.5 msec interval.The percentage of decrease in the amplitude of TS induced emg signal by CS inhibition is the cortical inhibition parameter.We repeat for 5 times and take the average.Then use 120%RMT both as CS and TS to evoke long-interval cortical inhibition(LICI)while it shouled be limited at 150 msec interval and repeat for 5 times to take the average.To the general counting data such as age and sex,we take the descriptice statistical analysis.To the measurement data,we take the One-way analysis of variance(ANOVA).Results:SICI and LICI were positively correlated with age in the normal group(R=-0.614,P=0.004).R=-0.499,P=0.025).SICI was positively correlated with age in the first-degree relative of schizophrenia group(R=-0.488,P=0.047),and LICI was positively correlated with age in the first-episode schizophrenia group(R=0.557,P=0.013).SICI of the first episode,the relief group,the relative group and the control group were 0.1295,0.1225,0.1006 and 0.1366,respectively,and their LICI were 0.0958,0.0995,0.0647 and 0.1300,respectively.SICI levels were significantly lower in the first-episode group,the remission group and the relative group than in the control group(P=0.019,P=0.008,P=0.001).However,only the relative group had significantly lower LICI(P=0.01).Conclusions:l.The cortical inhibitory function of normal healthy people changed with age.2.In patients with first-episode schizophrenia,short-term inhibition function in the cortex is impaired,and it persists in the stable phase of the disease,and will not improve with the improvement of symptoms.3.Compared with normal healthy people,the first-degree relatives of schizophrenia patients have reduced cortical inhibition,including short-term and long-term cortical inhibition.4.The difference of inhibitory function in the cortex was limited in patients with schizophrenia and their first-degree relatives.In summary,cortical inhibition is not associated with schizophrenia symptoms and drug efficacy,but may be associated with cognitive impairment,the results need further study.