Abstract :
Keywords Inter-trial variability; P300; Electroencephalography; Opiate; Posturography; Balance Highlights * Previous studies of patients with opiate abuse histories have not reliably detected neural or cognitive dysfunction. * Inter-trial variability in brain activation and postural control may be a more sensitive indicator than the mean level. * Analyses of variability revealed evidence of central nervous system (CNS) dysfunction. * Chronic opiate abuse may alter the temporal stability of the CNSresponse to external and internal stimuli. Abstract There is an abundant literature demonstrating the superiority of inter-trial variability (ITV) of reaction time over mean reaction time in the early identification of subtle cognitive processing decrements. The present study extends these ideas by examining brain activation and postural control ITV among participants with versus without a history of chronic opiate abuse. Participants enrolled in opiate abuse (n = 82) and control (n = 112) groups completed tasks that challenged selective attention and balance. During the respective tasks, the inter-trial variabilities in frontal P300a electroencephalographic responses and sway strategy scores outperformed their mean levels in differentiating the groups. The relevance of several potential alternative explanations for the differences, including premorbid conduct disorder and comorbid alcohol abuse, depression, and methadone use, was discounted via simultaneous or post hoc analyses. It appears that chronic opiate abuse has adverse CNS effects that persist into the protracted abstinence period. These effects alter the temporal stability of its response to external and internal stimuli. Author Affiliation: (a) Department of Psychiatry, University of Connecticut School of Medicine, Farmington, CT, USA * Correspondence to: Department of Psychiatry, Alcohol Research Center, University of Connecticut School of Medicine, 263 Farmington Avenue, Farmington, CT 06030-1410, United States. Article History: Received 18 April 2022; Revised 26 August 2022; Accepted 3 September 2022 Byline: Lance O. Bauer [lbauer@uchc.edu] (a,*)