title: Assessing cerebral dysfunction with probe-evoked potentials in a CNV task -- a study in alcoholics.
abstract: OBJECTIVE
  Contrary to event-related potential (ERP) components N1, N2 and P3, slow ERPs have rarely been used in assessing cerebral dysfunction in mental disorders. Focussing on slow waves (SWs) and on patients with mild cerebral dysfunction, we recorded ERPs in alcoholics using a dual task design.
  
  
  METHODS
  ERPs to auditory probes presented either 1s before the warning or 1s before the imperative stimulus of a visual contingent negative variation (CNV) paradigm were recorded from 33 scalp electrodes in 27 alcoholics following detoxification and 12 healthy controls. Independent component analysis (ICA) was used to separate potentially overlapping spatial components.
  
  
  RESULTS
  In alcoholics compared to controls, probe ERPs showed increased N2, decreased P3 and increased negative SWs of two types appearing pre- and post-P3, respectively. Both negative SWs significantly correlated with neuropsychological indices reflecting verbal intelligence and memory functions. The increase in probe-evoked N1 and P3 potentials during CNV, putatively associated with enhanced cortical excitability, significantly correlated with clinical features of protracted alcohol withdrawal syndrome in alcoholics.
  
  
  CONCLUSIONS
  Our experimental approach revealed two types of negative SWs which strongly correlated with neuropsychological deficits of mildly impaired patients. It is suggested that our methods might enhance diagnostic efficiency of ERPs. An electrophysiological measure of protracted alcohol withdrawal might be useful for managing central nervous system dysfunction in alcoholics.
authors.affiliation: Department of Psychiatry and Psychotherapy, Albert-Ludwigs-University Freiburg, Hauptstrasse 5, 79104 Freiburg, Germany. hans_olbrich@psyallg.ukl.uni-freiburg.de
authors.forename: Hans M
authors.initials: HM
authors.lastname: Olbrich
authors.forename: Helga
authors.initials: H
authors.lastname: Maes
authors.forename: Gabriele
authors.initials: G
authors.lastname: Valerius
authors.forename: Jens M
authors.initials: JM
authors.lastname: Langosch
authors.forename: Horst
authors.initials: H
authors.lastname: Gann
authors.forename: Bernd
authors.initials: B
authors.lastname: Feige
mesh_terms: D000328:Adult; D000430:Alcohol Withdrawal Delirium / Q000503:physiopathology; D000437:Alcoholism / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000503:physiopathology; D003072:Cognition Disorders / Q000503:physiopathology*; D003265:Contingent Negative Variation; D006801:Humans; D008875:Middle Aged; D009483:Neuropsychological Tests