title: Different forms of prefrontal theta burst stimulation for executive function of medication- resistant depression: Evidence from a randomized sham-controlled study.
abstract: BACKGROUND
  Even during symptomatic remission, many patients with medication resistant depression (MRD) still demonstrate impaired cognitive function, especially executive function (EF). Theta-burst transcranial magnetic stimulation (TBS) modulates cortical excitability and may treat MRD. Evidences from previous studies show that intermittent TBS (iTBS) produces cortical excitatory effects, while continuous TBS (cTBS) produces a reduction of cortical excitability. EF is highly dependent on prefrontal activity, but the effects of different forms of prefrontal TBS on EF remain unknown.
  
  
  METHODS
  60 MRD patients were recruited and randomly assigned to one of four groups. Treatment was determined by the group to which an individual was assigned; A: cTBS 1800pulses/session; B: iTBS 1800pulses/session; C: a combination of cTBS+iTBS, 1800pulses/session for each; and D: sham TBS. Wisconsin Card Sorting Test (WCST) for the performance of EF was evaluated before and after 10 daily treatment sessions
  
  
  RESULTS
  Repeated measures ANOVA, with each WCST index at baseline and 2weeks after TBS as within-subject factors, demonstrated that a statistically significant interaction of TBS groups (G) and antidepressant responses [(R), responses were defined as >50% reduction of depression scores after 2-weeks TBS treatment] on the before-versus-after changes of all WCST indexes (G×R, p<0.05). Responders in Group B, but not in the other groups, showed a significant improvement in WCST performance. Only nonresponders in Group A showed a trend for EF worsening.
  
  
  CONCLUSIONS
  Our findings showed that left prefrontal iTBS, not right prefrontal cTBS, improved EF, and this can be independent from its antidepressant effects.
authors.affiliation: Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Chih-Ming
authors.initials: CM
authors.lastname: Cheng
authors.affiliation: Institute of Cognitive Neuroscience, National Central University, Jhongli, Taiwan.
authors.forename: Chi-Hung
authors.initials: CH
authors.lastname: Juan
authors.affiliation: Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Mu-Hong
authors.initials: MH
authors.lastname: Chen
authors.affiliation: Institute of Cognitive Neuroscience, National Central University, Jhongli, Taiwan.
authors.forename: Chi-Fu
authors.initials: CF
authors.lastname: Chang
authors.affiliation: Institute of Cognitive Neuroscience, National Central University, Jhongli, Taiwan.
authors.forename: Hsin Jie
authors.initials: HJ
authors.lastname: Lu
authors.affiliation: Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Tung-Ping
authors.initials: TP
authors.lastname: Su
authors.affiliation: Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Ying-Chiao
authors.initials: YC
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Division of Psychiatry, Faculty of Medicine, National Yang-Ming University, Taipei, Taiwan. Electronic address: ctil2@vghtpe.gov.tw.
authors.forename: Cheng-Ta
authors.initials: CT
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D003071:Cognition / Q000502:physiology; D061218:Depressive Disorder, Treatment-Resistant / Q000503:physiopathology / Q000628:therapy*; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult
keywords: Brain stimulation; Cognitive function; Executive function; Medication-resistant depression; Theta-burst stimulation