title: Time perception in patients with major depressive disorder during vagus nerve stimulation.
abstract: BACKGROUND
  Affective disorders may affect patients' time perception. Several studies have described time as a function of the frontal lobe. The activating eff ects of vagus nerve stimulation on the frontal lobe might also modulate time perception in patients with major depressive disorder (MDD).
  
  
  METHODS
  Time perception was investigated in 30 patients with MDD and in 7 patients with therapy-resistant MDD. In these 7 patients, a VNS system was implanted and time perception was assessed before and during stimulation. A time estimation task in which patients were asked "How many seconds have passed?" tested time perception at 4 defined time points (34 s, 77 s, 192 s and 230 s). The differences between the estimated and actual durations were calculated and used for subsequent analysis.
  
  
  RESULTS
  Patients with MDD and healthy controls estimated the set time points relatively accurately. A general linear model revealed a significant main eff ect of group but not of age or sex. The passing of time was perceived as significantly slower in patients undergoing VNS compared to patients with MDD at all time points (T34: t = − 4.2; df = 35; p < 0.001; T77: t = − 4.8; df = 35; p < 0.001; T192: t = − 2.0; df = 35; p = 0.059; T230 t = −2.2; df = 35; p = 0.039) as well as compared to healthy controls (at only T77: t = 4.1; df = 35; p < 0.001). There were no differences in time perception with regard to age, sex or polarity of depression (uni- or bipolar).
  
  
  CONCLUSIONS
  VNS is capable of changing the perception of time. This discovery furthers the basic research on circadian rhythms in patients with psychiatric disorders.
authors.affiliation: Department of Psychiatry and Psychotherapy, University Hospital of Erlangen , Friedrich Alexander University of Erlangen , Erlangen , Germany. teresa.biermann@uk-erlangen.de
authors.forename: T
authors.initials: T
authors.lastname: Biermann
authors.forename: S
authors.initials: S
authors.lastname: Kreil
authors.forename: T W
authors.initials: TW
authors.lastname: Groemer
authors.forename: C
authors.initials: C
authors.lastname: Maihöfner
authors.forename: T
authors.initials: T
authors.lastname: Richter-Schmiedinger
authors.forename: J
authors.initials: J
authors.lastname: Kornhuber
authors.forename: W
authors.initials: W
authors.lastname: Sperling
mesh_terms: D000328:Adult; D000928:Antidepressive Agents / Q000627:therapeutic use; D003131:Combined Modality Therapy; D003865:Major Depressive Disorder / Q000188:drug therapy / Q000523:psychology* / Q000628:therapy*; D061218:Depressive Disorder, Treatment-Resistant / Q000188:drug therapy / Q000523:psychology* / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D013998:Time Perception / Q000187:drug effects*; D055536:Vagus Nerve Stimulation / Q000379:methods / Q000523:psychology*
chemical_list: D000928:Antidepressive Agents