title: Prefrontal cortical blood flow predicts response of depression to rTMS.
abstract: BACKGROUND
  Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for resistant major depressive disorder. The response rate of rTMS for depression is modest, motivating the search for biomarkers predictive of treatment response.
  
  
  METHODS
  Thirteen patients (mean age 45 years, three males) with current major depression resistant to at least one antidepressant trial in the current episode were treated with a 25 day course of rTMS over the left dorsolateral prefrontal cortex (DLPFC). Resting state cerebral perfusion was measured prior to the first day of treatment and after the final day of treatment. Treatment response was measured using the Hamilton Depression Rating Scale-24 Item (Ham-D). Baseline cerebral perfusion was compared in responders to non-responders. In addition, post-treatment cerebral perfusion was compared to pre-treatment in responders as well as in non-responders.
  
  
  RESULTS
  Six individuals responded to rTMS. Responders had greater resting state blood flow in the left DLPFC (the target site) at baseline compared to non-responders. Non-responders showed greater baseline activity in the left medial frontal cortex. Neither group exhibited changes during treatment, nor did the combined group.
  
  
  CONCLUSIONS
  This study suffers from low sample size and resulting small responder and non-responder subgroups. The sample was not balanced to gender. A normal control group was not included.
  
  
  CONCLUSIONS
  We believe this is the first study to compare pre-treatment brain perfusion patterns of depressed individuals who responded to rTMS to those who did not. Our results suggest stronger left DLPFC perfusion in responders and stronger medial prefrontal perfusion in non-responders both at baseline and post-treatment. These results await confirmation in a larger, prospective, placebo-controlled study.
authors.affiliation: Department of Radiology, Weill Cornell Medical College, New York, NY, United States.
authors.forename: Nora
authors.initials: N
authors.lastname: Weiduschat
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Dubin
mesh_terms: D000328:Adult; D003865:Major Depressive Disorder / Q000628:therapy*; D061218:Depressive Disorder, Treatment-Resistant / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D017397:Prefrontal Cortex / Q000098:blood supply* / Q000503:physiopathology; D011446:Prospective Studies; D050781:Transcranial Magnetic Stimulation; D016896:Treatment Outcome
keywords: Arterial spin labeling imaging; Biomarkers; Major depression; Prefrontal cortex; Regional cerebral blood flow; Transcranial magnetic stimulation