The Study On The EEG Characteristic Of The Excessive Internet User

People's work and lives are changing deeply because of Internet development. But in recent years,more and more young people use Internet excessively which hurts their physical and mental health and affect society and family harmony.The diagnosis for the excessive Internet use only employs the psychological evaluation methods and the treatment for it also only employs the psychological leading and drug intervention approach.There is not an objective physical standard for diagnosing it.In this study we applied electroencephalogram (EEG) method to study the EEG characteristic of excessive Internet user.The purpose is to provide some objective physical standards and theoretical basis for diagnosing and treating excessive Internet use.The main work of the dissertation includes the following five parts.(1) Study on the effect of excessive Internet use on the N400 of ERP by the experimentation of single Chinese character with semantically matching or mismatching ending strokes.The result showed the N400 had the obvious difference between excessive Internet users and normal subjects when they were confronted with mismatching ending strokes of single simple Chinese character. The N400 amplitudes of excessive Internet users were lower than normal subjects (P<0.05) and the N400 latency were more early than normal subjects(P<0.05).Otherwise the distribution of the N400 in the brain was more widely in the control team than in the trial team.(2) Study on the effect of excessive Internet use on the short-term memory.First, we found the short-term memory of excessive Internet users is obvious lower than that of normal subjects by analyzing the difference of short-term memory between two kinds of subjects. Second, we found the ERP of excessive Internet users has a differential wave on prefrontal electrode by analyzing the difference of ERP between two kinds of subjects when they are remembering and judging in short-term memory experiment.(3) Study on the effect of excessive Internet use on the EEG complexity by using the wavelet entropy (WE) method and complexity method.The result shows that the EEG's wavelet entropy value and complexity value of excessive Internet users before using Internet were obvious lower than that of normal subjects,and the wavelet entropy value and complexity value of excessive Internet users rise obviously after they have used Internet for 40 minutes which gets the similar level of normal subjects. (4) Study on the effect of excessive Internet use on time-frequency characteristic of EEG.First, study on the effect of excessive Internet use on the P300 of ERP by using auditory oddball task.The results demonstrated that excessive Internet use decreased P300 amplitudes increased P300 latency in all electrodes.Further, the F-test statistic of ERSP of the two groups of subjects was decomposed into two components by non-negative matrix factorization (NMF).From the NMF results the major effect of excessive Internet use on gamma oscillation occurred at approximately 300 ms after stimuli at around 40 to 50 Hz on the parietal central region.(5) Study on the effect of excessive Internet use on the synchronization of gamma oscillation and ERP components. We analysed the time-frequency characteristic of ERP in auditory oddball task and single Chinese character experiment by using the short-time Fourier transform (STFT) method.The results show that the gamma oscillation of normal subjects is strongly phase-locked with the endogenous components of ERP in two experiments.But to excessive Internet users the gamma oscillation is obvious weaker than normal subjects and the synchronization of the activity of gamma oscillation is obvious later than normal subjects.