Concurrent fNIRS and EEG for Brain Function Investigation: A Systematic, Methodology-Focused Review.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) are leading non-invasive neuroimaging techniques.
• EEG offers high temporal resolution but poor spatial resolution; fNIRS provides better spatial resolution with lower temporal resolution.
• The portability of both EEG and fNIRS facilitates multimodal integration for enhanced brain activity analysis.

Purpose of the Study:

• To critically review and summarize current analysis methods for concurrent fNIRS-EEG studies.
• To provide an up-to-date overview and guideline for future multimodal neuroimaging research.
• To address the unclear methodological references in existing concurrent fNIRS-EEG studies.

Main Methods:

• A comprehensive literature search was conducted on PubMed and Web of Science up to August 31, 2021.
• 92 studies involving concurrent fNIRS-EEG data recording and analysis were selected for methodological review.
• Analysis methods were categorized into EEG-informed fNIRS, fNIRS-informed EEG, and parallel fNIRS-EEG analyses.

Main Results:

• Identified and described three primary categories of concurrent fNIRS-EEG data analysis methodologies.
• Detailed explanations were provided for each analysis approach: EEG-informed fNIRS, fNIRS-informed EEG, and parallel fNIRS-EEG.
• The review highlighted the current challenges and potential future research directions in this field.

Conclusions:

• Concurrent fNIRS-EEG analysis methods are diverse, with three main categories identified.
• This review serves as a crucial guideline for researchers conducting multimodal fNIRS-EEG studies.
• Further research is needed to address existing challenges and explore new directions in concurrent fNIRS-EEG data analysis.