title: Non-linear EEG analyses predict non-response to rTMS treatment in major depressive disorder.
abstract: OBJECTIVE
  Several linear electroencephalographic (EEG) measures at baseline have been demonstrated to be associated with treatment outcome after antidepressant treatment. In this study we investigated the added value of non-linear EEG metrics in the alpha band in predicting treatment outcome to repetitive transcranial magnetic stimulation (rTMS).
  
  
  METHODS
  Subjects were 90 patients with major depressive disorder (MDD) and a group of 17 healthy controls (HC). MDD patients were treated with rTMS and psychotherapy for on average 21 sessions. Three non-linear EEG metrics (Lempel-Ziv Complexity (LZC); False Nearest Neighbors and Largest Lyapunov Exponent) were applied to the alpha band (7-13 Hz) for two 1-min epochs EEG and the association with treatment outcome was investigated.
  
  
  RESULTS
  No differences were found between a subgroup of unmedicated MDD patients and the HC. Non-responders showed a significant decrease in LZC from minute 1 to minute 2, whereas the responders and HC showed an increase in LZC.
  
  
  CONCLUSIONS
  There is no difference in EEG complexity between MDD and HC and the change in LZC across time demonstrated value in predicting outcome to rTMS.
  
  
  CONCLUSIONS
  This is the first study demonstrating utility of non-linear EEG metrics in predicting treatment outcome in MDD.
authors.affiliation: Research Institute Brainclinics, 6524AD Nijmegen, The Netherlands; Utrecht University, Department of Experimental Psychology, Utrecht, The Netherlands. Electronic address: martijn@brainclinics.com.
authors.forename: Martijn
authors.initials: M
authors.lastname: Arns
authors.affiliation: Research Group Complex Systems, Antonio Nariño University, Bogota, Colombia; Faculty of Electronic and Biomedical Engineering, Antonio Nariño University, Bogota, Colombia.
authors.forename: Alexander
authors.initials: A
authors.lastname: Cerquera
authors.affiliation: Research Group Complex Systems, Antonio Nariño University, Bogota, Colombia.
authors.forename: Rafael M
authors.initials: RM
authors.lastname: Gutiérrez
authors.affiliation: School of Pedagogical and Educational Science, Radboud University, Nijmegen, The Netherlands; Behavioural Science Institute: Learning & Plasticity, Radboud University Nijmegen, The Netherlands.
authors.forename: Fred
authors.initials: F
authors.lastname: Hasselman
authors.affiliation: Research Group Theoretical Physics and Complex Systems, ICBM, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg, Germany; Research Center Neurosensory Science, Carl von Ossietzky Universität Oldenburg, D-26111 Oldenburg, Germany.
authors.forename: Jan A
authors.initials: JA
authors.lastname: Freund
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D003865:Major Depressive Disorder / Q000175:diagnosis* / Q000628:therapy*; D016002:Discriminant Analysis; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D011379:Prognosis; D011613:Psychotherapy; D012372:ROC Curve; D012815:Signal Processing, Computer-Assisted; D050781:Transcranial Magnetic Stimulation; D016896:Treatment Outcome; D055815:Young Adult
keywords: Depression; EEG; Lempel–Ziv complexity; Non-linear analysis; Personalized medicine; Signal processing; rTMS