Hypofrontality in drug-free schizophrenic patients revealed by EEG coherence analysis

Abstracts

532. BEG RESONANT RESPONSES TO PHOTIC STIMULATION FOLLOWING SDZ MAR-327 TREATMENT Y. Jin, S.O. Potkin, & C. eezar Department of Psychiatry and Human Behavior. UC ]rvine Medical Center, 101 City Drive South, Omnge. CA 92668 Ten mnlc patients Wilh schizophrenia were treated with SOZ MAR-327. a dopamine D2 receplor partial agonist, in a double-blind crossover design. EEG photic driving and clinicalllsscssmllnts with PANSS, CGI llnd ESRS were perfonned utthe end of a six -week period of lreatmenl. EEQ photic driving was measured as responses to all the hannonic components of a I·Hz narrow pulsed (0.05 msec) photic stimulation which was provided through a Nehon Kohden strobe light. Data of photic driving WaS analyzed using nonlint:ur curvc fitting to reflect the chaf'.1cteristics of the EEQ resonance for each subject. Paired t·tests revealed that patients' clinical symptoms were significantly improved following Ihe MAR·327 treatment (PO.OS). Compared wilh the plncebo, MAR-327 significantly decreased lhe peak frequency nnd increased the selectivily (Q faclor) of the EEG resonOnl response, while the peak amplilude of the resonance remained unch3llged (P>O. 1). Posilive correlations were observed between the EEG resonant peak frequency and the scores of lolal PANSS. positive PANSS and global PANSS, i.e., the lower the frequency, the less Severe the symptoms, panicularly the positive symptoms. Q fllctor also was found to be signilicantly correlated with the change of total PANSS and positive PANSS, but not negative PANSS, i.e.• the higher the EEG resonant selectivity. the grealer the clinical improvement, especially in the posilive symptoms. These findings sussestthat the EEG resonance lo the photic stimulation may be used 3S lln objeclive measure in psychophnnnacologieul sludies.

533. THE EFFECTS OF CLOZAPINE ON SLEEP EEG IN BIPOLAR ILLNESS R. Armitage, T. Suppes, D. Cole, & A.J. Rush

DlOL PSYCHIATRY 1996;39:500-666

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#MH46886, & HK21; Launer Foundation: Mental HC:llth Connections; Sarah M, and Chnrlcs E, Scay Cenler for Bmin :mu Applicd Research in Psychiatric Illness.

534. HYPOFRONTALITY IN DRUG-FREE SCHIZOPHRENIC PATIENTS REVEALED BY BEG COHERENCE ANALYSIS J. Tauscher 1.2 , p, Rappelsberger, A. Neumeister', & S. Kasper' 'Department of Gcncml Psychiatry. University of Vienml, A- 1090 Vienna, Austria. Wachringer Guenel 18-20~ ~Institute of Neurophysiology, University of Vienna, A-I090 Vienna, Austria, Waehringcrstr. ]7 Dysfunction of cortical areas may contribule to infonnnlion·proccssing deficits in schizophrenia, Reduced blood now in the dorsohlleral prefrontal cortex during cognitive lIctivation requiring "working memory" lead to Ihe concept of "hypofrontalily". The objective of our study was 10 investigate whether EEG coherence analysis can be usetl to depict infonnation.processing deficits in scldzophrenic patients. EEG of J5 medication-free schizophrenic ra~icnts and 16 healthy controls were recorded. Avcmgcd power spectra and cross-power spcctl'll between selected elcctrode p3irs were computed for si" standard frequency bands, as wetl as coherence and mean amplitudes per frequency band. During the recordings the subjects hllll to perform a shape recognition task and menIal arithmetic. The obtained spcctrnl·parametcrs were compared with baseline 3ctivity with open eyes at rest. Differences were presented in spcctral,pllrnmctcr maps and results of statistical eVllluations (paired Wilcoxon tests) in probability maps. Only healthy controls showed an increase of della· nnd a decrease of alpha.amplitudes under cognitive load. During the shape recognition task. tlO increusc of cohercnce in lhe theta-band pariettltly WIlS seen in bOlh groups. Howevcr, significant (p
The University of Texns Southweslern Medielll Center, Dallas, TX Previous work in our labormory ha.Ii shown thai sleep BEG characteristics may be biological markers in unipolar depression. The prescnl study wns undertaken to describc sleep macro llnd microarchhceture in 15 symptomatic but medicated Bipolar I or schizoaffeclivc pUlients :It baseline and following six: months of treatment on Clolllpine. Sleep m::lcroarchi· tecture was evaluated with slandard visual stnge·scoring of sleep EEG recorded over 2 con~ccuti'Ve nights at each phase of study. Sleep microarchitecture was evaluated using period amplitude tlnlllysis to quantify SEQ frequencies. followed by crossspectral time series nnalysis to determine the periodicily and coherence of EEG rhythms between lind within the two cerebral hemispheres. Sleep latency, number of arousals, undtotal sleep period showed significant treatment effects all increasing clozapinc (p < .01). No sleep BEG coherence mc.'Ilsurcs showed significant treatment .:ffccts, although Ihe periodicity of EEO rhythms was about 40 minutes longer on c1ozapinc. Clozapine had n moocrllic effect on !\lcep macro vnrinblcs. but docs not ;lffcet sleep microarchitecture in bipolur patients. These findings nrc consistent with our previous work. that some sleep EEG abnonnalitics may show trait chamclcristics in affcctive disorders. Supported by NARSAD; NIMH IIMH41 IIS,

535, BRAIN EEG ABNORMALITIES IN 300 HOSPITALIZED PREADOLESCENTS N.K. Gehm & H.A, Nasrallah The Ohio Stale University, Department of Psychiatry. Columbus, OU 43210 In an era of mantlged health care, the cO~l·effcctiveness of eyery laboratory procedure must be ~lablishcd. All electroencephalograph (EEO) is on expensive but pOh:ntially useful diagnostic 1001 in psychiatric bmin disorders. We conducled a study to examine the yield of brain abnonnalitics detected by EEG in a population of hospilnlilcd prcudolesecnl pllticnls. The records of ull conscculive admissions to our preadolescent psychiatric unit over II period of 5 years (n=300) were