title: Cognition and sensation in very high static magnetic fields: a randomized case-crossover study with different field strengths.
abstract: OBJECTIVE
  To establish the extent to which representative cognitive functions in subjects undergoing magnetic resonance (MR) imaging are acutely impaired by static magnetic fields of varying field strengths.
  
  
  METHODS
  This study was approved by the local ethics committee, and informed consent was obtained from all subjects. In this single-blind case-crossover study, 41 healthy subjects underwent an extensive neuropsychologic examination while in MR units of differing field strengths (1.5, 3.0, and 7.0 T), including a mock imager with no magnetic field as a control condition. Subjects were blinded to field strength. Tests were performed while subjects were lying still in the MR unit and while the examination table was moved. The tests covered a representative set of cognitive functions, such as memory, eye-hand coordination, attention, reaction time, and visual discrimination. Subjective sensory perceptions were also assessed. Effects were analyzed with a repeated-measures analysis of variance; the within-subject factors were field strength (0, 1.5, 3.0, and 7.0 T) and state (static, dynamic).
  
  
  RESULTS
  Static magnetic fields were not found to have a significant effect on cognitive function at any field strength. However, sensory perceptions did vary according to field strength. Dizziness, nystagmus, phosphenes, and head ringing were related to the strength of the static magnetic field.
  
  
  CONCLUSIONS
  Static magnetic fields as high as 7.0 T did not have a significant effect on cognition.
authors.affiliation: Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Square J5, D-68159 Mannheim, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Heinrich
authors.forename: Anne
authors.initials: A
authors.lastname: Szostek
authors.forename: Patric
authors.initials: P
authors.lastname: Meyer
authors.forename: Frauke
authors.initials: F
authors.lastname: Nees
authors.forename: Jaane
authors.initials: J
authors.lastname: Rauschenberg
authors.forename: Jens
authors.initials: J
authors.lastname: Gröbner
authors.forename: Maria
authors.initials: M
authors.lastname: Gilles
authors.forename: Georgios
authors.initials: G
authors.lastname: Paslakis
authors.forename: Michael
authors.initials: M
authors.lastname: Deuschle
authors.forename: Wolfhard
authors.initials: W
authors.lastname: Semmler
authors.forename: Herta
authors.initials: H
authors.lastname: Flor
mesh_terms: D000293:Adolescent; D000328:Adult; D003071:Cognition / Q000528:radiation effects*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D018592:Cross-Over Studies; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D060526:Magnetic Fields / Q000009:adverse effects*; D008279:Magnetic Resonance Imaging / Q000009:adverse effects*; D008297:Male; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D012677:Sensation / Q000528:radiation effects*; D012678:Sensation Disorders / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D055815:Young Adult