Influence of isotropic skull models on EEG source localization

Area of Science:

• Medical Imaging and Neuroscience
• Biomedical Engineering

Background:

• Accurate electroencephalogram (EEG) source localization is crucial for understanding brain activity.
• The conductivity of the human skull significantly influences EEG signal propagation.
• Simplified head models are often used to reduce computational complexity in EEG analysis.

Purpose of the Study:

• To evaluate the impact of simplified skull geometries on the accuracy of EEG source localization.
• To compare the performance of heterogeneous and homogeneous conductivity models for simplified skulls.
• To quantify localization errors introduced by skull simplification.

Main Methods:

• Generation of four simplified head models from CT and MR images.
• Modeling skull conductivity as both heterogeneous and homogeneous.
• Comparison against a reference model with a CT-segmented, accurate skull.
• Analysis of EEG source localization errors in different brain regions.

Main Results:

• Simplified skull geometries led to localization errors of approximately 1 cm.
• Errors were most pronounced for sources in the central and temporal brain regions.
• The degree of simplification in skull geometry directly influenced the magnitude of localization errors.

Conclusions:

• The use of simplified skull models in EEG analysis can compromise source localization accuracy.
• Careful consideration of skull geometry is necessary for reliable EEG source imaging.
• Further research is needed to develop optimized simplified models that balance accuracy and computational efficiency.