Functional Near Infrared Spectroscopy (fNIRS): An Emerging Neuroimaging Technology with Important Applications for the Study of Brain Disorders

Abstract

Functional near-infrared spectroscopy (fNIRS) is an emerging functional neuroimaging technology offering a relatively non-invasive, safe, portable, and low-cost method of indirect and direct monitoring of brain activity. Most exciting is its potential to allow more ecologically valid investigations that can translate laboratory work into more realistic everyday settings and clinical environments. Our aim is to acquaint clinicians and researchers with the unique and beneficial characteristics of fNIRS by reviewing its relative merits and limitations vis-à-vis other brain-imaging technologies such as functional magnetic resonance imaging (fMRI). We review cross-validation work between fMRI and fNIRS, and discuss possible reservations about its deployment in clinical research and practice. Finally, because there is no comprehensive review of applications of fNIRS to brain disorders, we also review findings from the few studies utilizing fNIRS to investigate neurocognitive processes associated with neurological (Alzheimer's disease, Parkinson's disease, epilepsy, traumatic brain injury) and psychiatric disorders (schizophrenia, mood disorders, anxiety disorders).

ACKNOWLEDGMENTS

The authors would like to thank members of Drexel University's Department of Psychology and School of Biomedical Engineering, Science and Health Systems for their continual support. The authors also acknowledge the University of Pennsylvania Department of Biomedical Engineering and Department of Neuropsychiatry, in particular the laboratory of Dr. Britton Chance, Dr. Ruben, and Raquel Gur, and that of Dr. Banu Onaral at Drexel. The authors would also like to thank Kambiz Pourezzei, Maulik Oza, Roberta Kresky, Sarah Levin, Ivan Panyavin, Jennifer Gallo, Tom Myers, and Ludivine Fonteyn for helpful discussion concerning this line of investigation. We would also like to acknowledge the Canadian Institutes of Health Research and the Natural Sciences and Engineering Research Council of Canada for support to the first and fourth authors, respectively.