10/20, 10/10, and 10/5 systems revisited: their validity as relative head-surface-based positioning systems

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• The international 10/20 system for electroencephalography (EEG) electrode placement has been extended to higher densities (10/10 and 10/5 systems) for improved spatial resolution.
• The effectiveness of these higher-density systems as relative head-surface-based positioning systems requires examination.

Purpose of the Study:

• To extend a virtual measurement algorithm to analyze the 10/10 and 10/5 EEG electrode positioning systems.
• To assess the spatial variability and effective spatial resolution of these systems across multiple subjects.

Main Methods:

• Developed virtual 10/10 and 10/5 measurement algorithms based on a previously established virtual 10/20 algorithm.
• Analyzed structural MR head and brain images from 17 healthy subjects.
• Normalized acquired scalp positions to Montreal Neurological Institute (MNI) stereotactic coordinates and assessed spatial variability.

Main Results:

• Precise landmark positions on the scalp were achieved when detailed rules for each system were provided.
• For the 10/5 system, 241 non-overlapping scalp positions were effectively set for multi-subject studies.
• The 10/10 system positions demonstrated good separation on the scalp without overlap.

Conclusions:

• Established a referential framework for determining the effective spatial resolutions of 10/20, 10/10, and 10/5 systems.
• Demonstrated the feasibility of using virtual algorithms for precise and reliable electrode positioning in higher-density EEG systems.
• Highlighted the importance of standardized rules for landmark placement to ensure accuracy and consistency in multi-subject EEG research.