Short separation channel location impacts the performance of short channel regression in NIRS

By Louis Gagnon, Robert J. Cooper, Meryem A. Yücel, Katherine L. Perdue, Douglas N. Greve, David A. Boas. NeuroImage, 2011

316 citations recorded by the source corpus.

Near-Infrared Spectroscopy (NIRS) allows the recovery of cortical oxy-and deoxyhemoglobin changes associated with evoked brain activity. NIRS is a back-reflection measurement making it very sensitive to the superficial layers of the head, i.e. the skin and the skull, where systemic interference occurs. As a result, the NIRS signal is strongly contaminated with systemic interference of superficial origin. A recent approach to overcome this problem has been the use of additional short source-detector separation optodes as regressors. Since these additional measurements are mainly sensitive to superficial layers in adult humans, they can be used to remove the systemic interference present in longer separation measurements, improving the recovery of the cortical hemodynamic response function (HRF). One question that remains to answer is whether or not a short separation measurement is required in close proximity to each long separation NIRS channel. Here, we show that the systemic interference occurring in the superficial layers of the human head is inhomogeneous across the surface of the scalp. As a result, the improvement obtained by using a short separation optode decreases as the relative distance between the short and the long measurement is increased. NIRS data was acquired on 6 human subjects both at rest and during a motor task consisting of finger tapping. The effect of distance between the short and the long channel was first quantified by recovering a synthetic hemodynamic response added over the resting-state data. The effect was also observed in the functional data collected during the finger tapping task. Together, these results suggest that the short separation measurement must be located as close as 1.5 cm from the standard NIRS channel in order to provide an improvement which is of practical use. In this case, the improvement in Contrast-to-Noise Ratio (CNR) compared to a standard General Linear Model (GLM) procedure without using any small separation optode reached 50 % for HbO and 100 % for HbR. Using small separations located farther than 2 cm away resulted in mild or negligible improvements only.

Subfields: Biomedical Engineering, Radiology, Nuclear Medicine and Imaging, Surgery

View Paper: https://www.semanticscholar.org/paper/b14ceec8e1db089eea148f810fdb16b9c1a6a5e3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biomedical Engineering

In Radiology, Nuclear Medicine and Imaging

In Surgery

Citations in the corpus

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology (2014, background): “Gagnon et al. (2011, 2012) investigated how the position of the short SD channel relative to the long SD channel impacts the performance of the method.”
A Systematic Comparison of Motion Artifact Correction Techniques for Functional Near-Infrared Spectroscopy (2012, methodology): “Such amplitudes are consistent with those observed in real NIRS studies and have also been used in previous functional NIRS simulations (Gagnon et al., 2011, 2012).”
Current Status and Issues Regarding Pre-processing of fNIRS Neuroimaging Data: An Investigation of Diverse Signal Filtering Methods Within a General Linear Model Framework (2019, methodology): “We used different amplitudes for the HbO2 and HbR task-related components, with the HbR one being ∼-1/3 of the HbO2 component, as HbR has smaller changes than HbO2 (Gagnon et al., 2012).”
Statistical analysis of fNIRS data: A comprehensive review (2014, unknown): “Exploiting the short source–detector separation channels, numerous noise removal approaches have been developed (Gagnon et al., 2011, 2012, 2013; Saager and Berger, 2005, 2008; Saager et al., 2011; Umeyama and Yamada, 2009; Yamada et al., 2009; Zhang et al., 2007, 2009).”
The physiological origin of task-evoked systemic artefacts in functional near infrared spectroscopy (2012, background): “This assumption may be justified for haemodynamic fluctuations in capillaries or small vessels, but may be less accurate for the contribution of big arteries and veins supplying the scalp (Gagnon et al., 2012).”