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Abstract
In this comprehensive examination of EEG re-referencing techniques, I emphasize the critical role of referencing in EEG data analysis. The document underscores the paramountcy of selecting an ideally neutral reference, devoid of electrical activity, for accurate EEG measurements. It highlights the prevalent practices in EEG studies, such as employing single/double mastoid, Cz, or common average references, while cautioning against the potential distortions introduced by non-neutral references. The discussion extends to the BioSemi ActiveII system’s innovative open-loop feedback reference mechanism. Through a detailed discourse on whether to re-reference during data importing, the author reflects on EEGLAB’s recommendations for re-referencing to prevent significant data quality degradation, notably a 40dB signal-to-noise ratio loss with BioSemi data if not re-referenced. However, this practice does not come without drawbacks; specifically, it may eliminate a channel or affect the common average, influencing data analysis outcomes. The impact of re-referencing on Independent Component Analysis (ICA) is scrutinized, revealing potential reductions in common-mode signal amplitudes and the masking of less dominant non/cortical signals. Proposed solutions include foregoing re-referencing, post-ICA re-referencing, or adopting less aggressive methods. The document concludes by proposing the Reference Electrode Standardization Technique (REST) as an innovative alternative, marking a significant contribution to the discourse on EEG data processing methodologies.