title: Quantitative EEG and Low-Resolution Electromagnetic Tomography (LORETA) Imaging of Patients Undergoing Methadone Treatment for Opiate Addiction.
abstract: Methadone maintenance treatment (MMT) has been used as a treatment for opiate dependence since the mid-1960s. Evidence suggests that methadone binds to mu opiate receptors as do other opiates and induces changes in neurophysiological function. However, little is known, about how neural activity within the higher frequency gamma band (>30 Hz) while at rest changes in those stabilized on MMT despite its association with the excitation-inhibition balance within pyramidal-interneuron networks. Our study investigated differences in resting gamma power (37-41 Hz) between patients undergoing MMT for opiate dependence, illicit opiate users, and healthy controls subjects. Electroencephalographic data were recorded from 26 sites according to the international 10-20 system. Compared with the healthy controls subjects, people either undergoing MMT (mean difference [MD] = 0.32, 95% CI = 0.09-0.55, P < .01) or currently using illicit opiates (MD = 0.31, 95% CI = 0.06-0.56, P = .01) exhibited significant increased gamma power. The sLORETA (standardized low-resolution electromagnetic tomography) between-group comparison revealed dysfunctional neuronal activity in the occipital, parietal, and frontal lobes in the patients undergoing MMT. A more severe profile of dysfunction was observed in those using illicit opiates. Our findings suggest that long-term exposure to opioids is associated with disrupted resting state network, which may be reduced after MMT.
authors.affiliation: Department of Psychology, Auckland University of Technology, Auckland, New Zealand gwang@aut.ac.nz.
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Wang
authors.affiliation: Centre for Brain Research, University of Auckland, Auckland, New Zealand Department of Psychological Medicine, University of Auckland, Auckland, New Zealand.
authors.forename: Robert R
authors.initials: RR
authors.lastname: Kydd
authors.affiliation: Centre for Brain Research, University of Auckland, Auckland, New Zealand School of Pharmacy, University of Auckland, Auckland, New Zealand.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Russell
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000627:therapeutic use; D001931:Brain Mapping / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004569:Electroencephalography / Q000187:drug effects / Q000379:methods; D005260:Female; D065818:Gamma Rhythm / Q000187:drug effects*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D058850:Opiate Substitution Treatment / Q000379:methods; D009293:Opioid-Related Disorders / Q000503:physiopathology* / Q000517:prevention & control*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014054:Tomography / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D000701:Analgesics, Opioid; D008691:Methadone
keywords: EEG gamma; LORETA; methadone treatment; opiate addiction