title: Nocebo as headache trigger: evidence from a sham-controlled provocation study with RF fields.
abstract: BACKGROUND
  A large proportion of the population in Norway has experienced headache in connection with mobile phone use, but several double-blind provocation studies with radiofrequency (RF) and sham exposures have shown no relation between headache and mobile phone RF fields.
  
  
  OBJECTIVE
  To investigate the type and location of headache experienced by participants in one provocation study in order to gain insight into possible causes and mechanisms of the headaches.
  
  
  METHODS
  Questionnaire about headache, indication on figure of location of headache after exposure, interview with neurologist about headache features to make headache diagnoses.
  
  
  RESULTS
  The 17 participants went through 130 trials (sham or RF exposure). No significant difference existed in headache type, laterality or location between the headaches experienced with the two exposures types. In most participants, the headache was compatible with tension-type headache.
  
  
  CONCLUSIONS
  As participants experienced their typical 'mobile phone headache' both with and without RF exposure, and since the experiment did not involve the stress or the arm/head position of mobile phone use, the most likely explanation is that the headache in this situation is caused by negative expectations (nocebo).
  
  
  CONCLUSIONS
  This and other similar studies indicate that headache occurring in connection with mobile phone use is not related to RF fields, and that a nocebo effect is important for this and possibly other headache triggers.
authors.affiliation: St. Olav's Hospital, Norwegian National Headache Centre, Trondheim and Norwegian University of Science and Technology (NTNU), Department of Neuroscience, Trondheim, Norway. lars.stovner@ntnu.no
authors.forename: L J
authors.initials: LJ
authors.lastname: Stovner
authors.forename: G
authors.initials: G
authors.lastname: Oftedal
authors.forename: A
authors.initials: A
authors.lastname: Straume
authors.forename: A
authors.initials: A
authors.lastname: Johnsson
mesh_terms: D000328:Adult; D040421:Cell Phone; D004311:Double-Blind Method; D005260:Female; D020773:Headache Disorders / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway; D010147:Pain Measurement; D015990:Placebo Effect; D011846:Radio Waves / Q000009:adverse effects*; D012307:Risk Factors; D012718:Set, Psychology