Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging modality that uses low-levels of light to measure evoked hemodynamic changes in the brain. This technique has been growing in popularity over the last several decades due its versatility and portability and the applicability of this technique in unique experimental situations and subject populations, such as studies on children, infants, or using ecologically valid experimental designs (walking, social interaction, etc). As the number of end-users in this field grows, it is important to establish scientifically rigorous best practices for analysis and interpretation of these studies. A fallacy of the fNIRS field has been the direct import of methods and interpretations from other modalities (e.g. functional MRI) without proper adaptation and generalization for the fNIRS-specific noise and signal properties of the data. Furthermore, to date, the development of many fNIRS methods has been based on ad-hoc observations of these algorithms under specific datasets. As a result, end-users often use methods designed for statistical assumptions that do not match their own data. Failure to use proper statistical models or unmet assumptions often results in high false-positive rates and poor scientific rigor and this has been the case in many prior fNIRS studies. The goal of this Biomedical Research Group (BRG-R01) project is to establish current best practices for fNIRS analysis and an infrastructure for future development based on quantitative comparisons of methodologies via receiver operator characteristics analysis, quantification of bias, etc. This project will also establish an open-source fNIRS database to allow characterization and classification of the various properties of fNIRS signals and to quantify their effect on statistical models. Our group has a long history of fNIRS analysis and open-source software development over the last 15 years and is considered one of the top labs in fNIRS analysis.
The specific aims of this project are:
Aim 1. Development of an open fNIRS database and benchmarking platform for testing and characterizing the development of new algorithms and statistical methods.
Aim 2. Determination of best practices for fNIRS analysis under general and categorized noise models.
Aim 3. Continued development and improvement of fNIRS-specific analysis models with focus on end-user needs and feedback.
Aim4. Dissemination and training of methods.
Functional near-infrared spectroscopy is a novel neuroimaging method with a growing number and diversity of end-users. While numerous analysis and statistical methods have been proposed in this field, there has been little attempt to quantify the performance, limitations, and generalizability of these methods. This has lead to a generally low scientific rigor in much of the fNIRS field as end-users are forced to wade through the library of analysis methods; many of which make statistical assumptions that do not match the fNIRS data (e.g. spherical, uncorrelated noise). This BRG project will provide quantitative infrastructure including the first open fNIRS database to compare current and future best practices for fNIRS analysis.
