title: Differentiating cortical patterns of cognitive dysfunction in schizophrenia and posttraumatic stress disorder.
abstract: Comparative studies are needed to determine whether the cognitive impairments found in various psychiatric disorders are specific to those disorders, or are a more universal consequence of mental illness. This study compares the patterns of cognitive dysfunction in two conditions characterized by working memory dysfunction, schizophrenia and posttraumatic stress disorder (PTSD). Three matched groups (Schizophrenia, PTSD, Control) of 16 subjects had event related potentials recorded, using a 27 electrode array, while they performed a working memory auditory target detection task. Both disorders were associated with impaired task performance, with greater impairment in schizophrenia. Reduction in N1 amplitude was found only in schizophrenia, and an increase in target N2 amplitude and latency was found only in PTSD. Both patient groups showed a reduction in the amplitude of the non-target and target P3, but the groups were distinguished by a reduction in non-target parietal P3 amplitude in the schizophrenia group and a reduction in target P3 amplitude over the left posterior parietal region in the PTSD Group. This study demonstrates that there are specific patterns of cognitive dysfunction associated with schizophrenia and with PTSD.
authors.affiliation: Discipline of Psychiatry, School of Medicine, University of Adelaide, Elanor Harrald Building, Frome Rd, Adelaide 5000, South Australia, Australia. cherrie.galletly@adelaide.edu.au
authors.forename: Cherrie A
authors.initials: CA
authors.lastname: Galletly
authors.forename: Alexander C
authors.initials: AC
authors.lastname: McFarlane
authors.forename: Richard
authors.initials: R
authors.lastname: Clark
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001288:Attention / Q000502:physiology; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000503:physiopathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology*; D035061:Control Groups; D004569:Electroencephalography / Q000706:statistics & numerical data; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005625:Frontal Lobe / Q000503:physiopathology; D006801:Humans; D008568:Memory / Q000502:physiology*; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010296:Parietal Lobe / Q000503:physiopathology; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012559:Schizophrenia / Q000175:diagnosis / Q000503:physiopathology*; D012565:Schizophrenic Psychology; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology