The Potential of Functional Near-Infrared Spectroscopy-Based Neurofeedback—A Systematic Review and Recommendations for Best Practice

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Background: The effects of electroencephalography (EEG) and functional magnetic
resonance imaging (fMRI)-neurofeedback on brain activation and behaviors have
been studied extensively in the past. More recently, researchers have begun to
investigate the effects of functional near-infrared spectroscopy-based neurofeedback
(fNIRS-neurofeedback). FNIRS is a functional neuroimaging technique based on brain
hemodynamics, which is easy to use, portable, inexpensive, and has reduced sensitivity
to movement artifacts.
Method: We provide the first systematic review and database of fNIRS-neurofeedback
studies, synthesizing findings from 22 peer-reviewed studies (including a total of N = 441
participants; 337 healthy, 104 patients). We (1) give a comprehensive overview of
how fNIRS-neurofeedback training protocols were implemented, (2) review the online
signal-processing methods used, (3) evaluate the quality of studies using pre-set
methodological and reporting quality criteria and also present statistical sensitivity/power
analyses, (4) investigate the effectiveness of fNIRS-neurofeedback in modulating
brain activation, and (5) review its effectiveness in changing behavior in healthy and
pathological populations.