Practicality of wavelength selection to improve signal-to-noise ratio in near-infrared spectroscopy

Sato, Hiroki; Kiguchi, Masashi; Kawaguchi, Fumio; Maki, Atsushi

doi:10.1016/j.neuroimage.2003.12.017

Cited by 124 publications

(97 citation statements)

References 33 publications

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“…The system measures simultaneously at two wavelengths, 695 and 830 nm, to allow for the separate measurement of changes in oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (HbR) concentrations. This specific choice of wavelengths has been shown to minimize cross-talk error between the two chromophores (29).…”

Section: Methodsmentioning

confidence: 99%

Adaptive benefit of cross-modal plasticity following cochlear implantation in deaf adults

Anderson

Wiggins

Kitterick

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

114

134

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It has been suggested that visual language is maladaptive for hearing restoration with a cochlear implant (CI) due to cross-modal recruitment of auditory brain regions. Rehabilitative guidelines therefore discourage the use of visual language. However, neuroscientific understanding of cross-modal plasticity following cochlear implantation has been restricted due to incompatibility between established neuroimaging techniques and the surgically implanted electronic and magnetic components of the CI. As a solution to this problem, here we used functional near-infrared spectroscopy (fNIRS), a noninvasive optical neuroimaging method that is fully compatible with a CI and safe for repeated testing. The aim of this study was to examine cross-modal activation of auditory brain regions by visual speech from before to after implantation and its relation to CI success. Using fNIRS, we examined activation of superior temporal cortex to visual speech in the same profoundly deaf adults both before and 6 mo after implantation. Patients' ability to understand auditory speech with their CI was also measured following 6 mo of CI use. Contrary to existing theory, the results demonstrate that increased cross-modal activation of auditory brain regions by visual speech from before to after implantation is associated with better speech understanding with a CI. Furthermore, activation of auditory cortex by visual and auditory speech developed in synchrony after implantation. Together these findings suggest that cross-modal plasticity by visual speech does not exert previously assumed maladaptive effects on CI success, but instead provides adaptive benefits to the restoration of hearing after implantation through an audiovisual mechanism. cochlear implantation | cross-modal plasticity | functional near-infrared spectroscopy | superior temporal cortex | visual speech

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Section: Methodsmentioning

confidence: 99%

Adaptive benefit of cross-modal plasticity following cochlear implantation in deaf adults

Anderson

Wiggins

Kitterick

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

114

134

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“…Sato et al have suggested that noise levels in hemoglobin (Hb) changes decreased when using wavelengths shorter than 782 nm paired with 830 nm, although the detected power appears to be weaker at the shorter wavelength [21]. …”

Section: Methodsmentioning

confidence: 99%

Night duty and decreased brain activity of medical residents: a wearable optical topography study

Nishida

Kikuchi

Miwakeichi

et al. 2017

Medical Education Online

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Background: Overwork, fatigue, and sleep deprivation due to night duty are likely to be detrimental to the performance of medical residents and can consequently affect patient safety. Objective: The aim of this study was to determine the possibility of deterioration of cerebral function of sleep-deprived, fatigued residents using neuroimaging techniques. Design: Six medical residents were instructed to draw blood from artificial vessels installed on the arm of a normal cooperator. Blood was drawn at a similar time of the day, before and after night duty. To assess sleep conditions during night duty, the participants wore actigraphy units throughout the period of night duty. Changes in cerebral hemodynamics, during the course of drawing blood, were measured using a wearable optical topography system. Results: The visual analogue scale scores after night duty correlated negatively with sleep efficiency during the night duty (ρ = −0.812, p = 0.050). The right prefrontal cortex activity was significantly decreased in the second trial after night duty compared with the first (p = 0.028). The extent of [oxy-Hb] decrease, indicating decreased activity, in the right dorsolateral prefrontal cortex correlated negatively with the Epworth sleepiness score after night duty (ρ = −0.841, p = 0.036). Conclusions: Sleep deprivation and fatigue after night duty, caused a decrease in the activity of the right dorsolateral prefrontal cortex of the residents, even with a relatively easy routine. This result implies that the brain activity of medical residents exposed to stress on night duty, although not substantially sleep-deprived, was impaired after the night duty, even though they apparently performed a simple medical technique appropriately. Reconsideration of the shift assignments of medical residents is strongly advised. Abbreviations: DLPFC: Dorsolateral prefrontal cortex; ESS: Epworth sleepiness scale; PSQI: Pittsburgh sleep quality index; ROI: Regions of interest; VAS: Visual analogue scale; WOT: Wearable optical topography

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“…They showed that (i) 830 nm should be paired with 690 or 760, as well as that (ii) the wavelength range 770-800 nm provides only poor oxygenation information. Sato et al (2004) tested empirically (on four subjects performing different cognitive and motor tasks) which of the four wavelengths 678, 692, 750 and 782 nm is the best combination with 830 nm to obtain an optimal SNR for both [O 2 Hb] and [HHb]. 692 nm and 830 nm provided the highest SNR.…”

Section: Two Wavelengthsmentioning

confidence: 99%

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,481

1,394

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This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. Contents

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Practicality of wavelength selection to improve signal-to-noise ratio in near-infrared spectroscopy

Cited by 124 publications

References 33 publications

Adaptive benefit of cross-modal plasticity following cochlear implantation in deaf adults

Adaptive benefit of cross-modal plasticity following cochlear implantation in deaf adults

Night duty and decreased brain activity of medical residents: a wearable optical topography study

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

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