P300 asymmetry in schizophrenia: a meta-analysis

P300 event-related brain potential (ERP) amplitude is smaller in patients w ith schizophrenia compared to unaffected controls, but whether left tempora l component amplitude is also smaller is debated. The present study employe d meta-analytical methods to quantitatively assess previous P300 schizophre nia asymmetry findings. All P300 articles on schizophrenia using an auditor y oddball paradigm published before January 2000 were obtained by comprehen sive literature searches and cross-referencing for related articles. A tota l of 19 original articles reporting complete midline electrode data and 11 articles reporting lateral asymmetry electrode data were reviewed, which in cluded different independent conditions that yielded 50 independent data se ts. P300 amplitude differences between patients with schizophrenia and cont rol subjects from the midline electrodes yielded effect sizes that differed among recording sites, such that Fz was significantly smaller than Pz, wit h Cz effect sizes smaller than Pz but larger than Fz. Comparison of P300 am plitude from the lateral data for the T3 and T4 electrodes found no reliabl e effect size difference when these electrodes were analyzed separately. Ho wever, comparison of P300 amplitude effect sizes from the TCP1 was signific antly larger than that from the TCP2 when these electrodes were analyzed se parately. P300 amplitude is smaller overall in patients with schizophrenia compared to control subjects and differs in its effect size topography acro ss the midline and temporal electrode sites, with the strongest effect size s obtained for the Pz midline and TCP1 lateral electrodes. (C) 2001 Elsevie r Science Ireland Ltd. All rights reserved.