ASPOFAFF :: Journal - Volume 1 :: Issue 2 :: Vol 1 - Iss 2 - Short Communication - P300 Event related coherence analysis (P3ERCOH), showed abnormal responses in schizophrenic and psychotic patients but not in bipolar ones


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ASPOFAFF :: Journal - Volume 1 :: Issue 2 :: Vol 1 - Iss 2 - Short Communication - P300 Event related coherence analysis (P3ERCOH), showed abnormal responses in schizophrenic and psychotic patients but not in bipolar ones

Vol 1 - Iss 2 - Short Communication - P300 Event related coherence analysis (P3ERCOH), showed abnormal responses in schizophrenic and psychotic patients but not in bipolar ones #46

P300 Event related coherence analysis (P3ERCOH), showed abnormal responses in schizophrenic and psychotic patients but not in bipolar ones Aguilar L.C., Diaz M.F., Aguilar-Venegas L.C., Boom M: Instituto De Invesrigaciones En Neuroplasticidad Y Desorrollo Celular. Guadalajara, Japisco, México. lcac@prodigy.net.mx Clinical features of mania and psychotic behavior (mood-congruent grandiose delusions and hallucinations (not present in all cases) can occur, psychoses are related with multiple etiologies that usually affect limbic regions, frontal and temporal cortex, on the other hand, some psychoses may manifest schizophrenia – like illness with paranoid delusions and auditory hallucinations indistinguishable from those occurring in idiopathic schizophrenia. Event related coherence is a tool that can provide information regarding the dynamic interaction of spatially separated brain regions. Previous studies of EEG coherence demonstrate. reduced coupling between the frontal and temporal regions during talking in schizophrenic patients compared with healthy controls, while other studies detect a significant lower amount of inhibitory (gabaergic) neurons in postmortem schizophrenic patients. To understand the temporal relationships between averaged ERPs during auditory p300, we calculated event-related coherence phase locked over frontal, central, parietal occipital and temporal areas. Methods and Materials: In this study we analyzed 14 patients with diagnosis of bipolar I affective disorder (DSM-IV), 10 patients with schizophrenia (DSM-IV), 10 patients with psychoses and 26 healthy control subjects (CON) both sexes, between 20 to 40 years, similar years of education. The subjects were stimulated with typical auditory oddball task, using stim and the electroencephalographic activity was acquired and processed with Synamp 1 equipments and Neuroscan 4.3 software (Neuroscan co.) using 22 electrodes according with 10-20 international system, the event related coherence(ERcoh) (0.1-52.1 hz), face locked, was analyzed, quantified and compared between groups in 0-1000 ms segments after the stimulus, using t-test for comparing groups and z- transform for comparing individual patients with respect to controls, the difference between higher coherence (maximum coupling on) and lower coherence (maximum coupling off) was quantified every 200 ms for obtaining the differential between coupling on-off between regions. Results: All schizophrenic patients showed a significant reduction (p>0.0001) in differential coupling on-off with respect to healthy controls in all regions. Also, the levels of coherence were significantly (p<0.01) higher with respect to the control group, suggesting high coupling on and poor disconnection. A reduced coherence in fronto temporal right regions was detected in psychotic patient, suggesting a disconnection in all cases, but no abnormalities in the differential between coupling on-off in the other regions, suggesting adequate control in the connection disconnection mechanism between regions. No significant deviations in bipolar patients were observed with respect to healthy controls. Conclusions: The previous results suggest that the mechanism of disconnection is severely affected in schizophrenia in all regions, probably related with the reduction of gabaergic neurons, whereas in psychoses this mechanism is adequate, only the fronto-temporal right lobe showed abnormal disconnection, probably related to poor development or damage, thus findings in both pathologies were very different to bipolar patients where the level of coherence and the differential coupling on-off were normal, suggesting an intact mechanism for dynamic interaction between regions.

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