Short-channel regression in functional near-infrared spectroscopy is more effective when considering heterogeneous scalp hemodynamics.

Wyser, Dominik; Mattille, Michelle; Wolf, Martin; Lambercy, Olivier; Scholkmann, Felix; Gassert, Roger (2020). Short-channel regression in functional near-infrared spectroscopy is more effective when considering heterogeneous scalp hemodynamics. Neurophotonics, 7(3), 035011. SPIE 10.1117/1.NPh.7.3.035011

[img]
Preview
Text
035011_1.pdf - Published Version
Available under License Creative Commons: Attribution (CC-BY).

Download (2MB) | Preview

Significance: The reliability of functional near-infrared spectroscopy (fNIRS) measurements is reduced by systemic physiology. Short-channel regression algorithms aim at removing systemic "noise" by subtracting the signal measured at a short source-detector separation (mainly scalp hemodynamics) from the one of a long separation (brain and scalp hemodynamics). In literature, incongruent approaches on the selection of the optimal regressor signal are reported based on different assumptions on scalp hemodynamics properties. Aim: We investigated the spatial and temporal distribution of scalp hemodynamics over the sensorimotor cortex and evaluated its influence on the effectiveness of short-channel regressions. Approach: We performed hand-grasping and resting-state experiments with five subjects, measuring with 16 optodes over sensorimotor areas, including eight 8-mm channels. We performed detailed correlation analyses of scalp hemodynamics and evaluated 180 hand-grasping and 270 simulated (overlaid on resting-state measurements) trials. Five short-channel regressor combinations were implemented with general linear models. Three were chosen according to literature, and two were proposed based on additional physiological assumptions [considering multiple short channels and their Mayer wave (MW) oscillations]. Results: We found heterogeneous hemodynamics in the scalp, coming on top of a global close-to-homogeneous behavior (correlation 0.69 to 0.92). The results further demonstrate that short-channel regression always improves brain activity estimates but that better results are obtained when heterogeneity is assumed. In particular, we highlight that short-channel regression is more effective when combining multiple scalp regressors and when MWs are additionally included. Conclusion: We shed light on the selection of optimal regressor signals for improving the removal of systemic physiological artifacts in fNIRS. We conclude that short-channel regression is most effective when assuming heterogeneous hemodynamics, in particular when combining spatial- and frequency-specific information. A better understanding of scalp hemodynamics and more effective short-channel regression will promote more accurate assessments of functional brain activity in clinical and research settings.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Medical Education > Institute of Complementary and Integrative Medicine (IKIM)

UniBE Contributor:

Scholkmann, Felix Vishnu

Subjects:

600 Technology > 610 Medicine & health

ISSN:

2329-423X

Publisher:

SPIE

Language:

English

Submitter:

Andrea Stettler

Date Deposited:

26 Nov 2020 11:46

Last Modified:

02 Mar 2023 23:34

Publisher DOI:

10.1117/1.NPh.7.3.035011

PubMed ID:

33029548

Uncontrolled Keywords:

brain–computer interface functional near-infrared spectroscopy general linear model physiological systemic artifacts scalp hemodynamics short-channel regression

BORIS DOI:

10.7892/boris.148530

URI:

https://boris.unibe.ch/id/eprint/148530

Actions (login required)

Edit item Edit item
Provide Feedback