P Gargiulo1, P Belfiore2, E A Friðgeirsson3, S Vanhatalo4, C Ramon5. 1. Institute of Biomedical and Neural Engineering, Reykjavik University, Iceland; Department of Science, Landspitali University Hospital, Reykjavik, Iceland. 2. Department of Biomedical, Electronic and Telecommunication Engineering, University Federico II of Naples, Italy. 3. Department of Development CE and IT, Landspitali University Hospital, Reykjavik, Iceland. 4. 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. 5. Institute of Biomedical and Neural Engineering, Reykjavik University, Iceland; Department of Electrical Engineering, University of Washington, Seattle, WA 98195, USA.
Abstract
OBJECTIVE: To define how fontanels affect scalp EEG potentials in neonates. METHOD: 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. SIGNIFICANCE: Most neonatal EEG studies can be adequately performed without assuming distortions by fontanels.
OBJECTIVE: To define how fontanels affect scalp EEG potentials in neonates. METHOD: 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. SIGNIFICANCE: Most neonatal EEG studies can be adequately performed without assuming distortions by fontanels.
Authors: L Routier; M Mahmoudzadeh; M Panzani; H Azizollahi; S Goudjil; G Kongolo; F Wallois Journal: Hum Brain Mapp Date: 2017-01-23 Impact factor: 5.038