The Effect of Different High-Pass Filter Settings On Peak Latencies in the Event-Related Potentials of Schizophrenics, Patients With Parkinsons-Disease and Controls

K. P. Ebmeier, M. Glabus, D. D. Potter, E. A. Salzen

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    Eighteen schizophrenic patients. 16 patients with idiopathic Parkinson's disease, and the same numbers of age, sex and education matched controls were examined with oddball experiments for the generation of P3. Individual averages were high-pass filtered at different cut-off frequencies with single-pole digital filters with equivalent analogue Butterworth filter profiles. The purpose of this procedure was to simulate analogue high-pass filters used in clinical studies from different centres and to examine their potential effect on group differences. Increasing high-pass filters resulted in a phase lead for all peaks examined (N1. P2, N2, P3). The only group differences were found for P3, which showed a greater phase lead in controls than in the patient groups, usually resulting in a more pronounced group difference. Similar wave forms and filter properties could be modelled by synthetic wave forms consisting of sine waves of different frequencies.
    Original languageEnglish
    Pages (from-to)280-287
    Number of pages8
    JournalElectroencephalography and Clinical Neurophysiology
    Issue number3
    Publication statusPublished - 1992



    • Event-related potentials; schizophrenia; idiopathic parkinsons disease; high-pass filter; bandpass filter P300; depression; time

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