title: The effect of fontanel on scalp EEG potentials in the neonate.
abstract: OBJECTIVE
  To define how fontanels affect scalp EEG potentials in neonates.
  
  
  METHODS
  Realistic finite element method head models were generated with and without fontanels. The electrical activity of the whole cortex was simulated using distributed 54,620 concurrently active cortical dipoles with a uniform random distribution of current densities (0-40 μA/cm2). The overall effects of fontanels on scalp potentials were calculated from finite element forward solution in the vicinity the fontanel region by relative difference measure (RDM*) and magnification factor (MAG), and the skull conductivity was systematically varied from 0.003 to 0.3S/m.
  
  
  RESULTS
  The neonatal scalp EEG topographies are comparable in models with and without fontanels, with highest amplitudes directly above the anterior fontanel. Quantitatively, comparison of these models elicits negligible differences (RDM*) ∼2% and MAG ∼1.0). However, fontanel contribution to scalp potential was shown to increase sharply with decreases in skull conductivity.
  
  
  CONCLUSIONS
  These results suggest that fontanels may affect neonatal scalp EEG much less than traditionally assumed, and the effect is strongly dependent on skull conductivity.
  
  
  CONCLUSIONS
  Most neonatal EEG studies can be adequately performed without assuming distortions by fontanels.
authors.affiliation: Institute of Biomedical and Neural Engineering, Reykjavik University, Iceland; Department of Science, Landspitali University Hospital, Reykjavik, Iceland.
authors.forename: P
authors.initials: P
authors.lastname: Gargiulo
authors.affiliation: Department of Biomedical, Electronic and Telecommunication Engineering, University Federico II of Naples, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Belfiore
authors.affiliation: Department of Development CE and IT, Landspitali University Hospital, Reykjavik, Iceland.
authors.forename: E A
authors.initials: EA
authors.lastname: Friðgeirsson
authors.affiliation: Department of Children's Clinical Neurophysiology, HUS Medical Imaging Center and Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland. Electronic address: sampsa.vanhatalo@helsinki.fi.
authors.forename: S
authors.initials: S
authors.lastname: Vanhatalo
authors.affiliation: Institute of Biomedical and Neural Engineering, Reykjavik University, Iceland; Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA.
authors.forename: C
authors.initials: C
authors.lastname: Ramon
mesh_terms: D001931:Brain Mapping / Q000379:methods; D055762:Cranial Fontanelles / Q000033:anatomy & histology* / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D012535:Scalp / Q000033:anatomy & histology* / Q000502:physiology*
keywords: Head model; High density EEG; Neonatal EEG; Source localization