Preservation of EEG spectral power features during simultaneous EEG-fMRI

Area of Science:

• Neuroimaging
• Biomedical Engineering
• Signal Processing

Background:

• Simultaneous electroencephalography (EEG) and magnetic resonance imaging (fMRI) offer complementary insights into brain function.
• However, EEG data quality is compromised by artifacts, notably the ballistocardiographic (BCG) artifact from the MRI scanner.
• Effective BCG artifact correction is essential for reliable EEG-fMRI analysis.

Purpose of the Study:

• To characterize the impact of BCG artifacts on resting-state EEG spectral properties.
• To compare the effectiveness of seven common BCG correction methods in preserving EEG spectral features.
• To assess the retention of posterior alpha power reactivity and its utility in EEG-informed fMRI.

Main Methods:

• EEG data were recorded from 20 healthy adults inside and outside an MRI environment.
• Seven BCG correction methods were applied: AAS, OBS, ICA, and combinations thereof.
• Signal preservation was evaluated by comparing spectral power and alpha power reactivity to an eyes-closed/open task.

Main Results:

• BCG artifacts significantly distorted EEG spectral power across all frequency bands.
• All tested correction methods left residual artifacts or signal loss.
• ICA-based correction methods, especially with ICA feature extraction, best preserved EEG reactivity and alpha power fluctuations.
• This preservation enabled accurate prediction of hemodynamic signals in EEG-informed fMRI.

Conclusions:

• Current BCG correction software has limited efficiency for preserving EEG spectral properties in this setup.
• Advanced methods should be combined with hardware solutions for optimal EEG signal preservation during simultaneous EEG-fMRI.
• Validation of BCG correction methods must include assessment of both event-related potentials (ERPs) and spontaneous EEG spectral power.