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First-episode psychosis and direction of wave propagation at 1 Hz in the EEG

Published online by Cambridge University Press:  24 June 2014

D Alexander ,
P Boord ,
K Brown ,
P Das ,
G Flynn ,
C Galletly ,
E Gordon ,
A Harris ,
L Williams  and
W Wong
D Alexander
Affiliation:
Brain Resource Company, Sydney, Australia
P Boord
Affiliation:
Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney, Australia
K Brown
Affiliation:
Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney, Australia
P Das
Affiliation:
Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney, Australia Neuroscience Institute of Schizophrenia and Allied Disorders, Sydney, Australia
G Flynn
Affiliation:
Early Psychosis Intervention Program, Liverpool Hospital, NSW, Australia
C Galletly
Affiliation:
Department of Psychiatry, University of Adelaide, SA, Australia
E Gordon
Affiliation:
Brain Resource Company, Sydney, Australia
A Harris
Affiliation:
The University of Sydney, Sydney, Australia
L Williams
Affiliation:
Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney, Australia
W Wong
Affiliation:
Early Psychosis Intervention Program, Liverpool Hospital, NSW, Australia
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Abstract

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Type
Abstracts from ‘Brainwaves’— The Australasian Society for Psychiatric Research Annual Meeting 2006, 6–8 December, Sydney, Australia
Information
Acta Neuropsychiatrica , Volume 18 , Issue 6 , December 2006 , pp. 240
Copyright
Copyright © 2006 Blackwell Munksgaard

Background:

EEG measures of power and phase synchrony are related to symptom factors in subjects with first-episode psychosis (FEP). This study uses a new dynamical measure that detects event-related episodes of long-wavelength activity in the EEG.

Methods:

Data were acquired from 56 subjects with FEP and 112 matched controls. Positive and Negative Syndrome Scale was used to calculate three-factor scores for reality distortion (RD), psychomotor poverty (PP) and disorganization (Dis). EEG was measured during an auditory oddball task at 26 electrodes. The spatial patterns of phase gradients across the scalp were assessed using three orthonormal basis functions: anterior-posterior, peripheral-central and right-left. Correlations of the relative phases with each of the basis functions are denoted rAP, rPC and rRL, respectively.

Results:

The FEP group had greater values of rAP at ∼1 Hz than the controls, and rAP at ∼1 Hz correlated with PP, r = −0.57. The FEP group had greater values of rRL at ∼1 Hz than the controls, and rRL at ∼1 Hz correlated with RD, r = 0.55 and Dis, r = 0.53.

Conclusions:

In the approximately 1-Hz range, the FEP group showed directional differences in wave propagation, compared with controls. The greater tendency of the subjects with FEP to engage in right to left wave propagation was indicative of higher scores for RD and Dis. The lesser tendency of the subjects with FEP to engage in posterior to anterior wave propagation was, however, related to lower scores for PP. Differences for FEP in the global coordination of cortical inactivation are directly related to symptom clusters.