Hellmuth Obrig
Humboldt State University
25 Papers
203 Citations
Hellmuth Obrig is an academic researcher from Humboldt State University. The author has contributed to research in topics: Cerebral blood flow & Cerebral perfusion pressure. The author has an hindex of 8, co-authored 25 publications.
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Papers
Towards a standard analysis for functional near-infrared imaging.
Matthias L. Schroeter,Markus M. Bücheler,Karsten Müller,Kâmil Uludağ,Kâmil Uludağ,Hellmuth Obrig,Gabriele Lohmann,Marc Tittgemeyer,Arno Villringer,D. Yves von Cramon +9 more
TL;DR: The present study suggests that the general linear model and spatially resolved spectral analysis can be used as standard statistical approaches for optical imaging data, particularly because they are almost independent of the assumed differential path length factors.
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Bed-side assessment of cerebral perfusion in stroke patients based on optical monitoring of a dye bolus by time-resolved diffuse reflectance.
Adam Liebert,Heidrun Wabnitz,Jens Steinbrink,M. Möller,Rainer Macdonald,Herbert Rinneberg,Arno Villringer,Hellmuth Obrig +7 more
TL;DR: The study demonstrates the necessity of a technique with sub-nanosecond time resolution to allow for depth discrimination if clinical perfusion monitoring of cerebrovascular diseases is addressed by optical methods.
156
Cross talk in the Lambert-Beer calculation for near-infrared wavelengths estimated by Monte Carlo simulations.
TL;DR: Using the modified Lambert-Beer law to analyze attenuation changes measured noninvasively during functional activation of the brain might result in an insufficient separation of chromophore changes ("cross talk") due to the wavelength dependence of the partial path length of photons in the activated volume of the head.
137
Noninvasive monitoring of cerebral blood flow by a dye bolus method: Separation of brain from skin and skull signals
Matthias Kohl-Bareis,Hellmuth Obrig,Jens Steinbrink,Jasmin Malak,Kamil Uludag,Arno Villringer +5 more
TL;DR: This work studies optical absorption changes induced by a bolus of the dye indocyanine-green with near infrared spectroscopy in healthy volunteers to assess the latency and shape of the change in absorption.
97
Near-infrared spectroscopy in functional activation studies: Can NIRS demonstrate cortical activation?
Hellmuth Obrig,Arno Villringer +1 more
TL;DR: In this paper, a description of the typical NIRS response pattern over an activated cortical area is attempted, based on the reported findings and results from two studies by our own group.
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