Using preregistration as a tool for transparent fNIRS study design

Abstract

Significance: The expansion of functional near-infrared spectroscopy (fNIRS) methodology and analysis tools gives rise to various design and analytical decisions that researchers have to make. Several recent efforts have developed guidelines for preprocessing, analyzing, and reporting practices. For the planning stage of fNIRS studies, similar guidance is desirable. Study preregistration helps researchers to transparently document study protocols before conducting the study, including materials, methods, and analyses, and thus, others to verify, understand, and reproduce a study. Preregistration can thus serve as a useful tool for transparent, careful, and comprehensive fNIRS study design.Aim: We aim to create a guide on the design and analysis steps involved in fNIRS studies and to provide a preregistration template specified for fNIRS studies.Approach: The presented preregistration guide has a strong focus on fNIRS specific requirements, and the associated template provides examples based on continuous-wave (CW) fNIRS studies conducted in humans. These can, however, be extended to other types of fNIRS studies.Results: On a step-by-step basis, we walk the fNIRS user through key methodological and analysis-related aspects central to a comprehensive fNIRS study design. These include items specific to the design of CW, task-based fNIRS studies, but also sections that are of general importance, including an in-depth elaboration on sample size planning.Conclusions: Our guide introduces these open science tools to the fNIRS community, providing researchers with an overview of key design aspects and specification recommendations for comprehensive study planning. As such it can be used as a template to preregister fNIRS studies or merely as a tool for transparent fNIRS study design.

Validating the reproducibility of a low-cost single-channel fNIRS device across hierarchical cognitive tasks

“…Acknowledging the intricacies presented by this pilot study, we advocate for the adoption of preregistration in subsequent research endeavors. This approach, as championed by Schroeder et al (2023) , will enhance the clarity and reproducibility of our scientific inquiry, allowing the researcher to systematically address biases and substantiate the reliability of our results.…”

Successful Modulation of Temporoparietal Junction Activity and Stimulus-Driven Attention by fNIRS-based Neurofeedback – a Randomized Controlled Proof-of-Concept Study

“…However, we took care to keep the contribution of systemic physiological changes in our design to a minimum and assessed the robustness of the online analysis through an additional offline analysis using more stringent preprocessing methods. More state-of-the art online artifact control measures and signal processing methods (Klein and Kranczioch, 2019; Lühmann et al, 2020; Klein et al, 2022; Schroeder et al, 2023) are now available and can be used in future studies to sufficiently rule out the contributions of systemic physiology.…”

Mobile fNIRS for exploring inter-brain synchrony across generations and time

“…The missing values may be estimated using multiple imputation for small amounts of missing data, and interested researchers should take into account the multidimensionality of the missing data before doing so (Molenberghs et al, 2014 ). To maximize the generalizability of the findings and the benefit of participants' efforts, researchers must plan protocols for addressing missing data, and where possible, include these in the preregistration protocol (Schroeder et al, 2023 ).…”

“…Finally, we would like to urge that these processes be embedded in open science practices (Ayaz et al, 2022 ; Kelsey et al, 2023 ), beginning with preregistration where explicit intentions are established for the research prior to collecting data (for recommendations see: Schroeder et al, 2023 ). Following analysis, datasets should be publicly archived to promote transparency and re-use of data.…”