title: Localized potentiation of sleep slow-wave activity induced by prefrontal repetitive transcranial magnetic stimulation in patients with a major depressive episode.
abstract: BACKGROUND
  The effects of repetitive transcranial magnetic stimulation (rTMS) on sleep structure in major depression are currently unknown.
  
  
  OBJECTIVE
  To determine the effects of prefrontal rTMS on sleep electroencephalography (EEG) in major depression.
  
  
  METHODS
  In this open-label pilot study, twelve male patients with relatively mild depression, who had been medication-resistant, underwent 10 daily rTMS sessions over the left dorsolateral prefrontal cortex (DLPFC). Polysomnographic (PSG) data were recorded over four nights: Adaptation, Baseline, Post-1 (after the fifth rTMS session), and Post-2 (after the tenth rTMS session). Discrete Fourier Transform (DFT) band power analyses were performed to quantify delta and sigma band activities during Stages II-IV, and determine time courses of these activities between Baseline and Post-1 (first five sessions) and between Post-1 and Post-2 (last five sessions).
  
  
  RESULTS
  Post-hoc tests based on a three-way ANOVA model indicated significant delta power increase at F3 (t11 = -2.762, P = 0.018) during the first five sessions; however, sigma power was unchanged. No significant band power changes were observed during the second half. Stages II-IV (percent total sleep time) increased significantly during the first half (t12 = -2.43, P = 0.033). No other significant changes in sleep parameters or clinical correlations were observed.
  
  
  CONCLUSIONS
  The first five sessions of high frequency rTMS to the left DLPFC increase slow-wave activity (SWA) at F3, possibly reflecting locally enhanced synaptic plasticity induced by rTMS. This increased activity was not observed during the last half, possibly due to a homeostatic regulation mechanism intrinsic to SWA.
authors.affiliation: Laboratory of Neuromodulation, Kinkou Hospital, Kanagawa Psychiatric Center, Yokohama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Saeki
authors.forename: Motoaki
authors.initials: M
authors.lastname: Nakamura
authors.forename: Nobuhide
authors.initials: N
authors.lastname: Hirai
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Noda
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Hayasaka
authors.forename: Hideo
authors.initials: H
authors.lastname: Iwanari
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Hirayasu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D058256:Brain Waves / Q000502:physiology*; D003865:Major Depressive Disorder / Q000150:complications / Q000628:therapy*; D004569:Electroencephalography; D004576:Electromyography; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D017286:Polysomnography; D017397:Prefrontal Cortex / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000209:etiology / Q000628:therapy*; D050781:Transcranial Magnetic Stimulation