title: Hemispheric laterality and dimensional complexity in schizophrenia under sound and light stimulation.
abstract: The aim of the present study is to investigate the relationship between linear and non-linear activities in human electroencephalograms (EEGs) by examining the linear lateral asymmetry index and the correlation dimension as a non-linear measure of complexity and to typify the characteristics of EEGs between schizophrenic patients and normal controls. We recorded the EEG from 16 electrodes in 10 schizophrenics (6 males and 4 females) and 10 age-matched normal controls (10 males), and calculated their asymmetry indices. The asymmetry index shows which hemispheric activity is dominant through examination of interhemispheric pairs in the frequency domain with EEGs between two regions. We also estimated correlation dimension. Remarkably, lower dimensional complexities appeared on the brain regions, which had significantly lower brain activity, as determined by a lateral asymmetry analysis, in schizophrenics before sound and light (SL) stimulation. We may suggest the possibility of co-varying of both linear and non-linear properties. This co-varying phenomenon maintained after the SL stimulation. Furthermore, schizophrenic patients revealed opposite asymmetric patterns compared to normal controls, as well as reversal phenomena and abnormalities in the left frontal region when SL stimuli were applied.
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, 305-701, Daejeon, South Korea.
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Jin
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Na
authors.forename: Soo Yong
authors.initials: SY
authors.lastname: Kim
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Ham
authors.forename: Dong Hyung
authors.initials: DH
authors.lastname: Lee
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Hyoung
authors.initials: H
authors.lastname: Lee
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000328:Adult; D000704:Analysis of Variance; D004569:Electroencephalography / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D012559:Schizophrenia / Q000503:physiopathology*