Background: Schizophrenia is nowadays viewed as a general cognitive disorder characterized by relatively stable cognitive impairments. Event-related potentials offer an approach for eliciting neurophysiological correlates of cognitive functioning. The P300 event-related brain potential (ERP) is an index of endogenous cognitive processes. Objective: This study sought to determine whether P300 can indicate the change in cognitive functions in schizophrenic patients and to evaluate its value in predicting remission. Methods: We studied 93 schizophrenic patients and 30 controls over 2 years. The age, gender, marital status, level of education and occupation were analyzed. Patients were assessed by the following scales: scales for assessment of positive and negative symptoms (SAPS and SANS) of schizophrenia and Wechsler Memory scale (WMS). Neurophysiological assessment with Event-related potentials (P300) was done for patients and control groups. Patients were maintained on antipsychotics whether typical or atypical, followed regularly twice per month over 6 months and they were reassessed with the same tools of assessment. Results: A total of 93 patients were studied; they were 60 males and 33 females with a mean age of 22.56±7.07 years. There was a significant difference between patients and control as regard all P300 variables. Treatment with antipsychotics led to variable degree of improvement in most cognitive scales. P300 amplitude was the only P300 variable which showed improvement with antipsychotics. On doing regression analysis, significant correlation (R²=0.599, F=55.05) was found between P300 amplitude and positive symptoms (SAPS). Conclusion: P300 is a useful tool for assessing cognitive functions and predicting remission in schizophrenic patients. [Egypt J Neurol Psychiat Neurosurg. 2011; 48(3): 241-246]
Key Words: Schizophrenia, Event related potential, P300, Cognition.
Correspondence to Ashraf Ahmed Zaher, Lecturer of neurology, Faculty of medicine, University of Mansoura, Egypt.
Tel.: +20122816432 E-mail ashrafdr2000@yahoo.com