Effects of magnetic stray fields from a 7 Tesla MRI scanner on neurocognition: a double-blind randomised crossover study

Occup Environ Med doi:10.1136/oemed-2011-100468

• Practice

• Original article

Effects of magnetic stray fields from a 7 Tesla MRI scanner on neurocognition: a double-blind randomised crossover study

1. Lotte E van Nierop1, 
2. Pauline Slottje1, 
3. Martine J E van Zandvoort2, 
4. Frank de Vocht3,
5. Hans Kromhout1

+Author Affiliations

1. ¹Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
2. ²Helmholz Institute, Utrecht University, Utrecht, The Netherlands
3. ³Centre for Occupational and Environmental Health, School of Community Based Medicine, University of Manchester, Manchester, UK

1. Correspondence toProfessor Dr Hans Kromhout, Institute for Risk Assessment Sciences, Utrecht University, PO Box 80178, Utrecht 3508 TD, The Netherlands; h.kromhout@uu.nl

1. Contributors HK and FV conceived the study. LEvN designed the original protocol supervised by PS, MJEvanZ and HK. All authors were involved in amending the protocol. LEvN coordinated the data collection. Data entry and analysis was carried out by LEvN under the supervision of PS and HK. LEvN wrote the first draft of the manuscript and all authors contributed to subsequent and final drafts.

• Accepted 3 May 2012
• Published Online First 27 August 2012

Abstract

Objective This study characterises neurocognitive domains that are affected by movement-induced time-varying magnetic fields (TVMF) within a static magnetic stray field (SMF) of a 7 Tesla (T) MRI scanner.

Methods Using a double-blind randomised crossover design, 31 healthy volunteers were tested in a sham (0 T), low (0.5 T) and high (1.0 T) SMF exposure condition. Standardised head movements were made before every neurocognitive task to induce TVMF.

Results Of the six tested neurocognitive domains, we demonstrated that attention and concentration were negatively affected when exposed to TVMF within an SMF (varying from 5.0% to 21.1% per Tesla exposure, p<0 .05=".05" addition="addition" affected="affected" after="after" exposure="exposure" high="high" in="in" memory="memory" orientation="orientation" p="0.05).</font" particular="particular" per="per" performance="performance" required.="required." situations="situations" tesla="tesla" visuospatial="visuospatial" was="was" were="were" working="working">

Conclusion Neurocognitive functioning is modulated when exposed to movement-induced TVMF within an SMF of a 7 T MRI scanner. Domains that were affected include attention/concentration and visuospatial orientation. Further studies are needed to better understand the mechanisms and possible practical safety and health implications of these acute neurocognitive effects.

http://oem.bmj.com/content/early/2012/07/26/oemed-2011-100468.abstract?papetoc