Virtual MEG Helmet: Computer Simulation of an Approach to Neuromagnetic Field Sampling

Mordekhay Medvedovsky, Jukka Nenonen, Alexandra Koptelova, Anna Butorina, Ritva Paetau, Jyrki P. Mäkelä, Antti Ahonen, Juha Simola, Tomer Gazit, Samu Taulu

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Head movements during an MEG recording are commonly considered an obstacle. In this computer simulation study, we introduce an approach, the virtual MEG helmet (VMH), which employs the head movements for data quality improvement. With a VMH, a denser MEG helmet is constructed by adding new sensors corresponding to different head positions. Based on the Shannon's theory of communication, we calculated the total information as a figure of merit for comparing the actual 306-sensor Elekta Neuromag helmet to several types of the VMH. As source models, we used simulated randomly distributed source current (RDSC), simulated auditory and somatosensory evoked fields. Using the RDSC model with the simulation of 360 recorded events, the total information (bits/sample) was 989 for the most informative single head position and up to 1272 for the VMH (addition of 28.6%). Using simulated AEFs, the additional contribution of a VMH was 12.6% and using simulated SEF only 1.1%. For the distributed and bilateral sources, a VMH can provide a more informative sampling of the neuromagnetic field during the same recording time than measuring the MEG from one head position. VMH can, in some situations, improve source localization of the neuromagnetic fields related to the normal and pathological brain activity. This should be investigated further employing real MEG recordings.

Original languageEnglish
Article number7014222
Pages (from-to)539-548
Number of pages10
JournalIEEE Journal of Biomedical and Health Informatics
Issue number2
Publication statusPublished - Mar 2016
Externally publishedYes


  • Internal magnetostatic multipole moments
  • magnetoencephalography
  • total information
  • virtual MEG helmet (VMH)


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