title: Cordance derived from REM sleep EEG as a biomarker for treatment response in depression--a naturalistic study after antidepressant medication.
abstract: OBJECTIVE
  To evaluate whether prefrontal cordance in theta frequency band derived from REM sleep EEG after the first week of antidepressant medication could characterize the treatment response after 4 weeks of therapy in depressed patients.
  
  
  METHODS
  20 in-patients (15 females, 5 males) with a depressive episode and 20 healthy matched controls were recruited into 4-week, open label, case-control study. Patients were treated with various antidepressants. No significant differences in age (responders (mean ± SD): 45 ± 22) years; non-responders: 49 ± 12 years), medication or Hamilton Depression Rating Scale (HAM-D) score (responders: 23.8 ± 4.5; non-responders 24.5 ± 7.6) at inclusion into the study were found between responders and non-responders. Response to treatment was defined as a ≥50% reduction of HAM-D score at the end of four weeks of active medication. Sleep EEG of patients was recorded after the first and the fourth week of medication. Cordance was computed for prefrontal EEG channels in theta frequency band during tonic REM sleep.
  
  
  RESULTS
  The group of 8 responders had significantly higher prefrontal theta cordance in relation to the group of 12 non-responders after the first week of antidepressant medication. This finding was significant also when controlling for age, gender and number of previous depressive episodes (F1,15 = 6.025, P = .027). Furthermore, prefrontal cordance of all patients showed significant positive correlation (r = 0.52; P = .019) with the improvement of HAM-D score between the inclusion week and fourth week of medication.
  
  
  CONCLUSIONS
  The results suggest that prefrontal cordance derived from REM sleep EEG could provide a biomarker for the response to antidepressant treatment in depressed patients.
authors.affiliation: Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Marek
authors.initials: M
authors.lastname: Adamczyk
authors.affiliation: Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Mary
authors.initials: M
authors.lastname: Gazea
authors.affiliation: Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Wollweber
authors.affiliation: Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Holsboer
authors.affiliation: Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Dresler
authors.affiliation: Max Planck Institute of Psychiatry, Munich, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Steiger
authors.affiliation: Max Planck Institute of Psychiatry, Munich, Germany. Electronic address: pawlowski@psych.mpg.de.
authors.forename: Marcel
authors.initials: M
authors.lastname: Pawlowski
mesh_terms: D000328:Adult; D000465:Algorithms; D000704:Analysis of Variance; D000928:Antidepressive Agents / Q000494:pharmacology*; D016022:Case-Control Studies; D003863:Depression / Q000188:drug therapy*; D004569:Electroencephalography; D004585:Electrooculography / Q000379:methods; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000503:physiopathology*; D011569:Psychiatric Status Rating Scales; D012895:Sleep, REM / Q000502:physiology*; D013826:Theta Rhythm; D016896:Treatment Outcome
chemical_list: D000928:Antidepressive Agents
keywords: Antidepressants; Biomarker; Cordance; Depression; EEG; REM sleep