Looking for fNIRS Signature in Autism Spectrum: A Systematic Review Starting From Preschoolers

Accumulating evidence suggests that functional Near-Infrared Spectroscopy (fNIRS) can provide an essential bridge between our current understanding of neural circuit organization and cortical activity in the developing brain. Indeed, fNIRS allows studying brain functions through the measurement of neurovascular coupling that links neural activity to subsequent changes in cerebral blood flow and hemoglobin oxygenation levels. While the literature offers a multitude of fNIRS applications to typical development, only recently this tool has been extended to the study of neurodevelopmental disorders (NDDs). The exponential rise of scientific publications on this topic during the last years reflects the interest to identify a fNIRS signature as a biomarker of high translational value to support both early clinical diagnosis and treatment outcome. The purpose of this systematic review is to describe the updating clinical applications of fNIRS in NDDs, with a specific focus on preschool population. Starting from this rationale, a systematic search was conducted for relevant studies in different scientific databases (Pubmed, Scopus, and Web of Science) resulting in 13 published articles. In these studies, fNIRS was applied in individuals with Autism Spectrum Disorder (ASD) or infants at high risk of developing ASD. Both functional connectivity in resting-state conditions and task-evoked brain activation using multiple experimental paradigms were used in the selected investigations, suggesting that fNIRS might be considered a promising method for identifying early quantitative biomarkers in the autism field.

Automated summary

Accumulating evidence suggests that functional Near-Infrared Spectroscopy (fNIRS) can provide insights into neural circuit organization and cortical activity in the developing brain. fNIRS measures neurovascular coupling to study brain functions through changes in cerebral blood flow and oxygenation levels. The interest in identifying fNIRS as a potential biomarker for early diagnosis and treatment outcome in neurodevelopmental disorders (NDDs) is reflected in the increasing number of scientific publications on this topic. This systematic review focuses on the clinical applications of fNIRS in NDDs, particularly in preschool children. The selected studies indicate that fNIRS shows promise in identifying early quantitative biomarkers for Autism Spectrum Disorder (ASD) through resting-state functional connectivity and task-evoked brain activation.