ABSTRACT
OBJECTIVE: Schneiderian first-rank symptoms (FRS) and abnormal EEG gamma activity in schizophrenia have been reported independently to have a neurodevelopmental basis. We aimed to investigate spontaneous gamma power in two groups of first episode schizophrenia patients (those who experience FRS and those who do not). METHODS: A comparative hospital based study having 37neuroleptic naive male patients with schizophrenia divided into two groups-FRS(+) and FRS(-) groups based on the presence of FRS. Thirty age, sex, education and handedness matched individuals served as controls (N). All participants underwent a 192-channel resting Electroencephalography (EEG) recording. Gamma spectral power was calculated for low- (30-50 Hz) and high-gamma 1 & 2 (51-70 and 71-100 Hz) bands. Spectral power was compared between three groups using MANOVA and supplementary one-way ANOVA with Bonferroni test controlling for multiple comparisons. Linear regression was used to identifying predictor variables for FRS. Pearson correlation coefficient was computed between spectral power parameters and various clinical variables. RESULTS: Significantly higher high gamma band-1 power was observed over right frontal (p<0.05), parietal (p<0.05) and temporal (p<0.05) regions in FRS(+) than FRS(-) group and normal controls. Right parietal high gamma-1 power and paranoid cluster on PANSS significantly predicted number of FRS in total schizophrenia patients; paranoid cluster on PANSS showed significant correlation with number of FRS in FRS(+) group. CONCLUSION: Findings of our study add to the evidence that areas contained within the hetero modal association cortex are associated with FRS. The study findings also strengthen the neurodevelopmental basis of FRS in schizophrenia.
Subject(s)
Humans , Male , Education , Electroencephalography , Functional Laterality , Linear Models , Rabeprazole , SchizophreniaABSTRACT
BACKGROUNDS: Gamma band oscillatory activity is considered to be related to congnitive functions and illustrates that the concept of event-related oscillations bridges the gap between single neurons and neural assemblies. An event-related gamma oscillation is the time - locked responses of specific frequency, and can be identified by computing the amplitude frequency characteristics of the averaged event-related potentials(ERPs) after stimulation. OBJECTIVES: We purposed to present experimental paradigm to investigate @-band oscillation activities from the recording of ERPs by using auditory oddball paradigm and investigate the difference of @-band activity between schizophrenia and normal controls. METHODS: The ERPs resulting from auditory stimuli with oddball paradigm in a group of schizophrenics(n=11) and also a group of age-, sex- and handedness matched normal controls, were recorded by 128 channel EEG. The @-band oscillatory activities were calculated by using time-frequency wavelet decomposition of the signal between 20 and 80Hz. The @-band oscillatory activities of both groups were compared by t-test. RESULTS: The @-band oscillatory of the leads Fz,Gz and Pz of both groups were represented well in the time - frequency maps. Significant increases of the @-band activity in normal controls compared with schizophrenics were observed around 160 msec. 350msec. and 800 msec after stimulation. CONCLUSIONS: Our results suggested that the increment in @-band oscillatory activity during cognitive operations and decreased @-band activity in schizophrenics may be associated with the cognitive dysfunctions and the pathophyiology of the schizophrenia.