Comparing the Safety and Data Quality between Multiband and Single Band Simultaneous EEG/fMRI

Abstract

Introduction: Simultaneously recorded electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) using single band (SB) echo planar imaging is an established in vivo neuroimaging technique capable of providing unique insights into neural activity. The recent development of multiband fMRI (MB-fMRI) allows for faster sampling of neural activity with comparatively few drawbacks. However, simultaneous EEG/MB-fMRI has yet to be extensively validated for safety and potential data quality improvements. By using benchmark analysis methods, this study aimed to determine whether simultaneous EEG/MBfMRI is a safe and useful improvement over SB-fMRI. Methods: Initial pilot studies were first conducted to establish thermal safety and establish multiband factor choice. Following this, a main study simultaneously acquired EEG/fMRI on 16 participants (7 male, ages 20-39) who completed two sets of 16-minute resting-state and then two sets of 9-minute n-back task scans. Each set consisted of one MB and one SB pulse sequence with sequence type randomised within a set. Results: Thermometer measurements at the EEG electrode-skin interface showed similar heating profiles between the SB and MB scans. EEG analysis of both resting-state and task-based data showed similar data quality with no systematic differences in either EEG channel variances or spectral power. fMRI analysis showed few differences between MB and SB when analysing n-back data. However, MB showed large increases in statistical and spatial sensitivity in both fMRI resting-state and EEG/fMRI integration analyses. Discussion: Using EEG/MB-fMRI for certain tasks (e.g. n-back task) provides no particular advantages nor disadvantages. However, for studying the resting-state, MB-fMRI potentially allows for reduced scanning durations for equivalent statistical significance to be obtained or alternatively, improved significance for the same scanning duration. As such, simultaneous EEG/MB-fMRI is an attractive and viable alternative to SB-fMRI.