Measurement of Cranial Optical Path Length as a Function of Age Using Phase Resolved Near Infrared Spectroscopy

Duncan, A. R.; Meek, Judith; Clemence, M; Elwell, Clare E.; Fallon, Penny; Tyszczuk, L; Cope, M; Delpy, David T.

doi:10.1203/00006450-199605000-00025

Cited by 403 publications

(315 citation statements)

References 34 publications

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“…Duncan et al, 1995;Matcher et al, 1995a). The DPF was found to be age, gender and wavelength dependent and varies between subjects (Duncan et al, 1996;Essenpreis et al, 1993) and different tissues (Duncan et al, 1995). For example the average DPF for the adult head for 100 subjects given by Duncan et al is 6.53 ± 0.99, i.e.…”

Section: Modified Beer-lambert Law (Mbll)mentioning

confidence: 96%

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

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,531

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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Section: Modified Beer-lambert Law (Mbll)mentioning

confidence: 96%

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

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,531

1,394

View full text Add to dashboard Cite

show abstract

“…Changes in absorption at the discrete wavelengths were converted into concentration changes of O 2 Hb and HH using the modified Lambert-Beer law (Livera et al 1991), and incorporating a differential path-length factor of 4.0 to correct for scattering of photons within the tissue (Ferrari et al 1992;Duncan et al 1996). tHb was derived from the sum of O 2 Hb and HHb, where changes in tHb reflect changes in blood volume.…”

Section: Test Protocols and Measurementsmentioning

confidence: 99%

The physiological responses to repeated upper-body sprint exercise in highly trained athletes

et al. 2015

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sprint decrement of 11.7 ± 4.1 %. Cycle rate remained unchanged, whereas work per cycle progressively decreased (P < 0.05). m. triceps brachii and m. latissimus dorsi were highly desaturated already after the first sprint (all P < 0.05), whereas the response was delayed for m. biceps brachii and m. vastus lateralis. Correspondingly, increases in VO 2 mainly occurred over the first two sprints (P < 0.05) and plateaued at approximately 75 % of VO 2peak . 1RM correlated with power during the first four sprints and with average sprint power (r = 0.71-0.80, all P < 0.05), whereas VO 2peak correlated with power in the last three sprints (r = 0.60-0.71, all P < 0.05). Conclusions The main decrement in upper-body sprint performance was evident in the first five sprints, followed by highly desaturated muscles and a plateau in pulmonary oxygen uptake already after the first 2-3 sprints. While high maximal strength seems important for producing power, aerobic capacity correlates with power in the last sprints.Keywords Cross-country · Skiers · Cycle rate · Maximum strength · Oxygen saturation · Oxygen uptake · Power output Methods Twelve male elite cross-country skiers performed eight 8-s maximal poling sprints with a 22-s recovery while sitting on a modified SkiErg poling ergometer. Force, movement velocity, cycle rate, work per cycle, oxygen saturation in working muscles and pulmonary oxygen uptake were measured continuously. A 3-min all-out ergometer poling test determined VO 2peak , and 1 repetition maximum (1RM) strength was determined in a movementspecific pull-down. Results Average sprint power was 281 ± 48 W, with the highest power on the first sprint, a progressive decline in power output over the following four sprints, and a Abbreviations ATTCommunicated by Jean-René Lacour.

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“…Within brain tissue, light absorption at the abovementioned wavelengths is predominantly modulated by changes in the blood hemoglobin concentration. For the optical path-length corrections, we used values from the published literature of 5.92, 5.76, and 5.39 for the differential path-length factors at 780, 805, and 830 nm, respectively (Duncan et al, 1996).…”

Section: Data Processingmentioning

confidence: 99%

Water-Diffusion Slowdown in the Human Visual Cortex on Visual Stimulation Precedes Vascular Responses

Kohno

Sawamoto

Urayama

et al. 2009

J Cereb Blood Flow Metab

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We used magnetic resonance imaging (MRI) to investigate the temporal dynamics of changes in water diffusion and blood oxygenation level-dependent (BOLD) responses in the brain cortex of eight subjects undergoing visual stimulation, and compared them with changes of the vascular hemoglobin content (oxygenated, deoxygenated, and total hemoglobin) acquired simultaneously from intrinsic optical recordings (near infrared spectroscopy). The group average rise time for the diffusion MRI signal was statistically significantly shorter than those of the BOLD signal and total hemoglobin content optical signal, which is assumed to be the fastest observable vascular signal. In addition, the group average decay time for the diffusion MRI also was shortest. The overall time courses of the BOLD and optical signals were strongly correlated, but the covariance was weaker with the diffusion MRI response. These results suggest that the observed decrease in water diffusion reflects early events that precede the vascular responses, which could originate from changes in the extravascular tissue.

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Measurement of Cranial Optical Path Length as a Function of Age Using Phase Resolved Near Infrared Spectroscopy

Cited by 403 publications

References 34 publications

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

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

The physiological responses to repeated upper-body sprint exercise in highly trained athletes

Water-Diffusion Slowdown in the Human Visual Cortex on Visual Stimulation Precedes Vascular Responses

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