Quantitative evaluation of deep and shallow tissue layers' contribution to fNIRS signal using multi-distance optodes and independent component analysis

Funane, Tsukasa; Atsumori, Hirokazu; Katura, Takusige; Obata, Akiko; Sato, Hiroki; Tanikawa, Yukari; Okada, Eiji; Kiguchi, Masashi

doi:10.1016/j.neuroimage.2013.02.026

Cited by 141 publications

(153 citation statements)

References 96 publications

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“…To remove or isolate this global artifact, most methods have used temporal information, and often the temporal values of the short-distance measurement channel as a reference of superficial hemodynamic fluctuations for regression [9][10][11][12][13][14][15]. However, the inhomogeneity of the temporal patterns in the hemodynamic change of the superficial layers [16,17] or the temporal correlation between the hemodynamic responses in the scalp and in the cortex [7,8,18] negatively impacts such artifact-removal methods based on temporal information. In this study, by contrast, the spatial information of the optical paths of all observation channels, which are not affected by temporal inhomogeneity or correlation, is fully exploited for removing the scalp signals.…”

Section: Introductionmentioning

confidence: 99%

Extended hierarchical Bayesian diffuse optical tomography for removing scalp artifact

Shimokawa¹,

Kubo²,

Yamashita³

et al. 2013

Biomed. Opt. Express

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Abstract:Functional near-infrared spectroscopy (fNIRS) can noninvasively measure hemodynamic responses in the cerebral cortex with a portable apparatus. However, the observation signal in fNIRS measurements is contaminated by the artifact signal from the hemodynamic response in the scalp. In this paper, we propose a method to separate the signals from the cortex and the scalp by estimating both hemodynamic changes by diffuse optical tomography (DOT). In the inverse problem of DOT, we introduce smooth regularization to the hemodynamic change in the scalp and sparse regularization to that in the cortex based on the nature of the hemodynamic responses. These appropriate regularization models, with the spatial information of optical paths of many measurement channels, allow three-dimensional reconstruction of both hemodynamic changes. We validate our proposed method through two-layer phantom experiments and MRI-based head-model simulations. In both experiments, the proposed method simultaneously estimates the superficial smooth activity in the scalp area and the deep localized activity in the cortical area.

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Section: Introductionmentioning

confidence: 99%

Extended hierarchical Bayesian diffuse optical tomography for removing scalp artifact

Shimokawa¹,

Kubo²,

Yamashita³

et al. 2013

Biomed. Opt. Express

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show abstract

“…Another useful approach is to use ICA in combination with MD measurements as recently shown. [39][40][41][42] Combining the ICA approach with systemic measurements is promising. 43 In a recent study, Kirilina et al 30 proposed a denoising algorithm that uses regressors derived from the time dependency between the fNIRS and systemic signals.…”

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confidence: 99%

False positives and false negatives in functional near-infrared spectroscopy: issues, challenges, and the way forward

2016

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“…(6), can be ideally canceled out when k = 1 and The k, however, depends on the optical characteristics of the observed object. Several studies have reported a k value of approximately 1 for a human head [3,4]. In the experiment using the proposed method and phantom, k values of 1.34 ± 0.28 and 1.30 ± 0.33 were obtained at wavelengths of 770 nm and 840 nm, respectively; thus, these did not necessarily indicate the ideal value for removal of motion artifacts.…”

Section: Discussionmentioning

confidence: 85%

“…The extraneous baseline changes, referred to as motion artifacts, have troubled users ever since systems became commercially available. Although some useful methods for removing the scalp blood effect from fNIRS signal have been developed in recent years, including multidistance optode arrangement techniques [1][2][3][4] and diffusion optical imaging [5,6], the problem of motion artifacts has been left essentially unsolved. A study using optodes attached on the forehead area reported that multidistance NIRS methods are generally better in reducing movement artifacts than the conventional single distance NIRS [7].…”

Section: Introductionmentioning

confidence: 99%

Removal of motion artifacts originating from optode fluctuations during functional near-infrared spectroscopy measurements

Yamada

Umeyama

Ohashi³

2015

Biomed. Opt. Express

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Functional near-infrared spectroscopy (fNIRS) has been increasingly utilized for detecting human cerebral activity in many disciplines because of the potential for less-restraining conditions. However, users often suffer from motion artifacts originating from optode fluctuation during task execution when the task includes motion. In such cases, the optode fluctuation induces changes both in the reflection by hair and in the transmission between the optode and scalp. If part of the reflected light is directly received by the detector optode (short-circuited light), it will contaminate the fNIRS signal. The transmittance change at the optode-scalp gap will also contaminate the signal. In this study, we proposed an optical model on the influence of optode fluctuation on the fNIRS signal and a method for removing the influence. The model revealed the following: (1) the received short-circuited light and the gap transmittance change generated a baseline change in the detected light intensity, and (2) the signal from the tissues was downscaled with increases in the receiving intensity of short-circuited light. To avoid erroneous detection of short-circuited light, we developed a method that optically eliminated hair-reflected light from the detection using linearly polarized light sources and an orthogonally polarized analyzer. The method was validated with an optical phantom possessing a haired surface. The optical absorbance change of a close source-detector (S-D) pair equipped with polarizers was very similar to that of distant S-D pairs, even though these optodes were artificially fluctuated. By combining the multidistance optode arrangement technique with the short-circuited light elimination method, the measurement could effectively eliminate motion artifacts originating from optode fluctuation.

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Quantitative evaluation of deep and shallow tissue layers' contribution to fNIRS signal using multi-distance optodes and independent component analysis

Cited by 141 publications

References 96 publications

Extended hierarchical Bayesian diffuse optical tomography for removing scalp artifact

Extended hierarchical Bayesian diffuse optical tomography for removing scalp artifact

False positives and false negatives in functional near-infrared spectroscopy: issues, challenges, and the way forward

Removal of motion artifacts originating from optode fluctuations during functional near-infrared spectroscopy measurements

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