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Portable wireless and fibreless fNIRS headband compares favorably to a stationary headcap-based system. PLoS One 2022; 17:e0269654. [PMID: 35834524 PMCID: PMC9282617 DOI: 10.1371/journal.pone.0269654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/25/2022] [Indexed: 12/05/2022] Open
Abstract
This study’s purpose is to characterize the performance of a prototype functional near-infrared spectroscopy (fNIRS) headband meant to enable quick and easy measurements from the sensorimotor cortices. The fact that fNIRS is well-suited to ergonomic designs (i.e., their ability to be made wireless, their relative robustness to movement artifacts among other characteristics) has resulted in many recent examples of novel ergonomic fNIRS systems; however, the optical nature of fNIRS measurement presents an inherent challenge to measurement at areas of the brain underlying haired parts of the head. It is for this reason that the majority of ergonomic fNIRS systems that have been developed to date target the prefrontal cortex. In the present study we compared the performance of a novel, portable fNIRS headband compared with a stationary full headcap fNIRS system to measure sensorimotor activity during simple upper- and lower-extremity tasks, in healthy individuals >50 years of age. Both fNIRS systems demonstrated the expected pattern of hemodynamic activity in both upper- and lower-extremity tasks, and a comparison of the contrast-to-noise ratio between the two systems suggests the prototype fNIRS headband is non-inferior to a full head cap fNIRS system regarding the ability to detect a physiological response at the sensorimotor cortex during these tasks. These results suggest the use of a wireless and fibreless fNIRS design is feasible for measurement at the sensorimotor cortex.
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Zhao H, Frijia EM, Vidal Rosas E, Collins-Jones L, Smith G, Nixon-Hill R, Powell S, Everdell NL, Cooper RJ. Design and validation of a mechanically flexible and ultra-lightweight high-density diffuse optical tomography system for functional neuroimaging of newborns. NEUROPHOTONICS 2021; 8:015011. [PMID: 33778094 PMCID: PMC7995199 DOI: 10.1117/1.nph.8.1.015011] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/09/2021] [Indexed: 05/27/2023]
Abstract
Significance: Neonates are a highly vulnerable population. The risk of brain injury is greater during the first days and weeks after birth than at any other time of life. Functional neuroimaging that can be performed longitudinally and at the cot-side has the potential to improve our understanding of the evolution of multiple forms of neurological injury over the perinatal period. However, existing technologies make it very difficult to perform repeated and/or long-duration functional neuroimaging experiments at the cot-side. Aim: We aimed to create a modular, high-density diffuse optical tomography (HD-DOT) technology specifically for neonatal applications that is ultra-lightweight, low profile and provides high mechanical flexibility. We then sought to validate this technology using an anatomically accurate dynamic phantom. Approach: An advanced 10-layer rigid-flexible printed circuit board technology was adopted as the basis for the DOT modules, which allows for a compact module design that also provides the flexibility needed to conform to the curved infant scalp. Two module layouts were implemented: dual-hexagon and triple-hexagon. Using in-built board-to-board connectors, the system can be configured to provide a vast range of possible layouts. Using epoxy resin, thermochromic dyes, and MRI-derived 3D-printed moulds, we constructed an electrically switchable, anatomically accurate dynamic phantom. This phantom was used to quantify the imaging performance of our flexible, modular HD-DOT system. Results: Using one particular module configuration designed to cover the infant sensorimotor system, the device provided 36 source and 48 detector positions, and over 700 viable DOT channels per wavelength, ranging from 10 to ∼ 45 mm over an area of approximately 60 cm 2 . The total weight of this system is only 70 g. The signal changes from the dynamic phantom, while slow, closely simulated real hemodynamic response functions. Using difference images obtained from the phantom, the measured 3D localization error provided by the system at the depth of the cortex was in the of range 3 to 6 mm, and the lateral image resolution at the depth of the neonatal cortex is estimated to be as good as 10 to 12 mm. Conclusions: The HD-DOT system described is ultra-low weight, low profile, can conform to the infant scalp, and provides excellent imaging performance. It is expected that this device will make functional neuroimaging of the neonatal brain at the cot-side significantly more practical and effective.
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Affiliation(s)
- Hubin Zhao
- University College London, DOT-HUB, Department of Medical Physics and Biomedical Engineering, Biomedical Optics Research Laboratory, London, United Kingdom
- University of Glasgow, James Watt School of Engineering, Glasgow, United Kingdom
| | - Elisabetta M. Frijia
- University College London, DOT-HUB, Department of Medical Physics and Biomedical Engineering, Biomedical Optics Research Laboratory, London, United Kingdom
| | - Ernesto Vidal Rosas
- University College London, DOT-HUB, Department of Medical Physics and Biomedical Engineering, Biomedical Optics Research Laboratory, London, United Kingdom
| | - Liam Collins-Jones
- University College London, DOT-HUB, Department of Medical Physics and Biomedical Engineering, Biomedical Optics Research Laboratory, London, United Kingdom
| | | | - Reuben Nixon-Hill
- Gowerlabs Ltd., London, United Kingdom
- Imperial College London, Department of Mathematics, London, United Kingdom
| | - Samuel Powell
- Gowerlabs Ltd., London, United Kingdom
- Nottingham University, Department of Electrical and Electronic Engineering, Nottingham, United Kingdom
| | | | - Robert J. Cooper
- University College London, DOT-HUB, Department of Medical Physics and Biomedical Engineering, Biomedical Optics Research Laboratory, London, United Kingdom
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Li H, Liu W, Kan R. A compact low-noise photodiode detection system for chemiluminescence nitric oxide analyzer. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:046103. [PMID: 31043039 DOI: 10.1063/1.5082400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
A compact, low noise, and high gain photon detector with the size of 50 mm × 50 mm × 48 mm has been developed for a nitric oxide (NO) chemiluminescence analyzer based on a temperature-stabilized photodiode (PD). A deviation of 0.01 °C was realized based on the design of a highly precise temperature control system to avoid signal fluctuation and baseline drift caused by environmental temperature fluctuation. At an optimized temperature of 23 °C, the noise level of 0.088 mV of the PD detector with a gain of 1011 V/A was obtained. The limit of quantitative detection for NO achieved was 25 ppb (S/N = 10), and the coefficient of determination R2 was 0.999 in the range of 0.1-20 ppm.
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Affiliation(s)
- Hang Li
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Wenqing Liu
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Ruifeng Kan
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
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Zhao H, Cooper RJ. Review of recent progress toward a fiberless, whole-scalp diffuse optical tomography system. NEUROPHOTONICS 2018; 5:011012. [PMID: 28983490 PMCID: PMC5613216 DOI: 10.1117/1.nph.5.1.011012] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 08/28/2017] [Indexed: 05/23/2023]
Abstract
The development of a whole-scalp, high sampling-density diffuse optical tomography (DOT) system is a critical next step in the evolution of the field of diffuse optics. To achieve this with optical fiber bundles is extremely challenging, simply because of the sheer number of bundles required, and the associated challenges of weight and ergonomics. Dispensing with optical fiber bundles and moving to head-mounted optoelectronics can potentially facilitate the advent of a new generation of wearable, whole-scalp technologies that will open up a range of new experimental and clinical applications for diffuse optical measurements. Here, we present a concise review of the significant progress that has been made toward achieving a wearable, fiberless, high-density, whole-scalp DOT system. We identify the key limitations of current technologies and discuss the possible opportunities for future development.
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Affiliation(s)
- Hubin Zhao
- University College London, Biomedical Optics Research Laboratory, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
| | - Robert J. Cooper
- University College London, Biomedical Optics Research Laboratory, Department of Medical Physics and Biomedical Engineering, London, United Kingdom
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Funane T, Numata T, Sato H, Hiraizumi S, Hasegawa Y, Kuwabara H, Hasegawa K, Kiguchi M. Rearrangeable and exchangeable optical module with system-on-chip for wearable functional near-infrared spectroscopy system. NEUROPHOTONICS 2018; 5:011007. [PMID: 28924567 PMCID: PMC5591581 DOI: 10.1117/1.nph.5.1.011007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 08/14/2017] [Indexed: 05/04/2023]
Abstract
We developed a system-on-chip (SoC)-incorporated light-emitting diode (LED) and avalanche photodiode (APD) modules to improve the usability and flexibility of a fiberless wearable functional near-infrared spectroscopy (fNIRS) system. The SoC has a microprocessing unit and programmable circuits. The time division method and the lock-in method were used for separately detecting signals from different positions and signals of different wavelengths, respectively. Each module autonomously works for this time-divided-lock-in measurement with a high sensitivity for haired regions. By supplying [Formula: see text] of power and base and data clocks, the LED module emits both 730- and 855-nm wavelengths of light, amplitudes of which are modulated in each lock-in frequency generated from the base clock, and the APD module provides the lock-in detected signals synchronizing with the data clock. The SoC provided many functions, including automatic-power-control of the LED, automatic judgment of detected power level, and automatic-gain-control of the programmable gain amplifier. The number and the arrangement of modules can be adaptively changed by connecting this exchangeable modules in a daisy chain and setting the parameters dependent on the probing position. Therefore, users can configure a variety of arrangements (single- or multidistance combinations) of them with this module-based system.
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Affiliation(s)
- Tsukasa Funane
- Hitachi, Ltd., Research & Development Group, Center for Exploratory Research, Hatoyama, Saitama, Japan
- Address all correspondence to: Tsukasa Funane, E-mail:
| | - Takashi Numata
- Hitachi, Ltd., Research & Development Group, Center for Exploratory Research, Hatoyama, Saitama, Japan
| | - Hiroki Sato
- Hitachi, Ltd., Research & Development Group, Center for Exploratory Research, Hatoyama, Saitama, Japan
| | | | | | | | | | - Masashi Kiguchi
- Hitachi, Ltd., Research & Development Group, Center for Exploratory Research, Hatoyama, Saitama, Japan
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Yücel MA, Selb JJ, Huppert TJ, Franceschini MA, Boas DA. Functional Near Infrared Spectroscopy: Enabling Routine Functional Brain Imaging. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2017; 4:78-86. [PMID: 29457144 PMCID: PMC5810962 DOI: 10.1016/j.cobme.2017.09.011] [Citation(s) in RCA: 115] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Functional Near-Infrared Spectroscopy (fNIRS) maps human brain function by measuring and imaging local changes in hemoglobin concentrations in the brain that arise from the modulation of cerebral blood flow and oxygen metabolism by neural activity. Since its advent over 20 years ago, researchers have exploited and continuously advanced the ability of near infrared light to penetrate through the scalp and skull in order to non-invasively monitor changes in cerebral hemoglobin concentrations that reflect brain activity. We review recent advances in signal processing and hardware that significantly improve the capabilities of fNIRS by reducing the impact of confounding signals to improve statistical robustness of the brain signals and by enhancing the density, spatial coverage, and wearability of measuring devices respectively. We then summarize the application areas that are experiencing rapid growth as fNIRS begins to enable routine functional brain imaging.
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Affiliation(s)
- Meryem A. Yücel
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Juliette J. Selb
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Neurophotonics Center, Biomedical Engineering, Boston University, Boston, MA, USA
| | - Theodore J. Huppert
- Department of Radiology and Bioengineering, University of Pittsburg, Pittsburg, PA, USA
| | - Maria Angela Franceschini
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - David A. Boas
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
- Neurophotonics Center, Biomedical Engineering, Boston University, Boston, MA, USA
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Kassab A, Le Lan J, Tremblay J, Vannasing P, Dehbozorgi M, Pouliot P, Gallagher A, Lesage F, Sawan M, Nguyen DK. Multichannel wearable fNIRS-EEG system for long-term clinical monitoring. Hum Brain Mapp 2017; 39:7-23. [PMID: 29058341 DOI: 10.1002/hbm.23849] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 10/02/2017] [Accepted: 10/08/2017] [Indexed: 01/27/2023] Open
Abstract
Continuous brain imaging techniques can be beneficial for the monitoring of neurological pathologies (such as epilepsy or stroke) and neuroimaging protocols involving movement. Among existing ones, functional near-infrared spectroscopy (fNIRS) and electroencephalography (EEG) have the advantage of being noninvasive, nonobstructive, inexpensive, yield portable solutions, and offer complementary monitoring of electrical and local hemodynamic activities. This article presents a novel system with 128 fNIRS channels and 32 EEG channels with the potential to cover a larger fraction of the adult superficial cortex than earlier works, is integrated with 32 EEG channels, is light and battery-powered to improve portability, and can transmit data wirelessly to an interface for real-time display of electrical and hemodynamic activities. A novel fNIRS-EEG stretchable cap, two analog channels for auxiliary data (e.g., electrocardiogram), eight digital triggers for event-related protocols and an internal accelerometer for movement artifacts removal contribute to improve data acquisition quality. The system can run continuously for 24 h. Following instrumentation validation and reliability on a solid phantom, performance was evaluated on (1) 12 healthy participants during either a visual (checkerboard) task at rest or while pedalling on a stationary bicycle or a cognitive (language) task and (2) 4 patients admitted either to the epilepsy (n = 3) or stroke (n = 1) units. Data analysis confirmed expected hemodynamic variations during validation recordings and useful clinical information during in-hospital testing. To the best of our knowledge, this is the first demonstration of a wearable wireless multichannel fNIRS-EEG monitoring system in patients with neurological conditions. Hum Brain Mapp 39:7-23, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Ali Kassab
- Research Center, Centre Hospitalier Universitaire de Montréal, Université de Montréal, Montréal, Québec, H2X 0A9, Canada
| | - Jérôme Le Lan
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Julie Tremblay
- Research Center, Hôpital Sainte-Justine, Université de Montréal, Montréal, Québec, H3T 1C4, Canada
| | - Phetsamone Vannasing
- Research Center, Hôpital Sainte-Justine, Université de Montréal, Montréal, Québec, H3T 1C4, Canada
| | - Mahya Dehbozorgi
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Philippe Pouliot
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Québec, H3T 1J4, Canada.,Research Center, Montreal Heart Institute, Montréal, Québec, H1T 1C8, Canada
| | - Anne Gallagher
- Research Center, Hôpital Sainte-Justine, Université de Montréal, Montréal, Québec, H3T 1C4, Canada
| | - Frédéric Lesage
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Mohamad Sawan
- Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Québec, H3T 1J4, Canada
| | - Dang Khoa Nguyen
- Research Center, Centre Hospitalier Universitaire de Montréal, Université de Montréal, Montréal, Québec, H2X 0A9, Canada.,Department of Neurology, Hôpital Notre-Dame (Centre Hospitalier de l'Université de Montréal), Montréal, Québec, H2L 4M1, Canada
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8
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Kiguchi M, Funane T, Sato H. A novel measurand independent of the distance between the source and detector for continuous wave near-infrared spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:064301. [PMID: 28668007 DOI: 10.1063/1.4989791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A new measurand is proposed for use in continuous wave near-infrared spectroscopy (cw-NIRS). The conventional measurand of cw-NIRS is l△c, which is the product of the change in the hemoglobin concentration (△c) and the partial path lengh (l), which depends on the source-detector (SD) distance (d). The SD distance must remain constant during cw-NIRS measurements, and we cannot compare the l△c value with that obtained using a different SD distance. In addition, the conventional measurand obtained using the standard measurement style sometimes includes a contribution from the human scalp. The SD distance independent (SID) measurand obtained using multi-SD distances is proportional to the product of the change in hemoglobin concentration and the derivative of the partial path length for the deep region with no scalp contribution under the assumption of a layer model. The principle of SID was validated by the layered phantom study. In order to check the limitation of assumption, a human study was conducted. The value of the SID measurand for the left side of the forehead during working memory task was approximately independent of the SD distance between 16 and 32 mm. The SID measurand and the standardized optode arrangement using flexible SD distances in a head coordinate system must be helpful for comparing the data in a population study.
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Affiliation(s)
- Masashi Kiguchi
- Center for Exploratory Research, Hitachi, Ltd., Hatoyama, Saitama 350-0395, Japan
| | - Tsukasa Funane
- Center for Exploratory Research, Hitachi, Ltd., Hatoyama, Saitama 350-0395, Japan
| | - Hiroki Sato
- Center for Exploratory Research, Hitachi, Ltd., Hatoyama, Saitama 350-0395, Japan
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Chitnis D, Cooper RJ, Dempsey L, Powell S, Quaggia S, Highton D, Elwell C, Hebden JC, Everdell NL. Functional imaging of the human brain using a modular, fibre-less, high-density diffuse optical tomography system. BIOMEDICAL OPTICS EXPRESS 2016; 7:4275-4288. [PMID: 27867731 PMCID: PMC5102535 DOI: 10.1364/boe.7.004275] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/25/2016] [Accepted: 09/06/2016] [Indexed: 05/21/2023]
Abstract
We present the first three-dimensional, functional images of the human brain to be obtained using a fibre-less, high-density diffuse optical tomography system. Our technology consists of independent, miniaturized, silicone-encapsulated DOT modules that can be placed directly on the scalp. Four of these modules were arranged to provide up to 128, dual-wavelength measurement channels over a scalp area of approximately 60 × 65 mm2. Using a series of motor-cortex stimulation experiments, we demonstrate that this system can obtain high-quality, continuous-wave measurements at source-detector separations ranging from 14 to 55 mm in adults, in the presence of hair. We identify robust haemodynamic response functions in 5 out of 5 subjects, and present diffuse optical tomography images that depict functional haemodynamic responses that are well-localized in all three dimensions at both the individual and group levels. This prototype modular system paves the way for a new generation of wearable, wireless, high-density optical neuroimaging technologies.
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Chitnis D, Airantzis D, Highton D, Williams R, Phan P, Giagka V, Powell S, Cooper RJ, Tachtsidis I, Smith M, Elwell CE, Hebden JC, Everdell N. Towards a wearable near infrared spectroscopic probe for monitoring concentrations of multiple chromophores in biological tissue in vivo. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:065112. [PMID: 27370501 PMCID: PMC4957669 DOI: 10.1063/1.4954722] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The first wearable multi-wavelength technology for functional near-infrared spectroscopy has been developed, based on a custom-built 8-wavelength light emitting diode (LED) source. A lightweight fibreless probe is designed to monitor changes in the concentrations of multiple absorbers (chromophores) in biological tissue, the most dominant of which at near-infrared wavelengths are oxyhemoglobin and deoxyhemoglobin. The use of multiple wavelengths enables signals due to the less dominant chromophores to be more easily distinguished from those due to hemoglobin and thus provides more complete and accurate information about tissue oxygenation, hemodynamics, and metabolism. The spectroscopic probe employs four photodiode detectors coupled to a four-channel charge-to-digital converter which includes a charge integration amplifier and an analogue-to-digital converter (ADC). Use of two parallel charge integrators per detector enables one to accumulate charge while the other is being read out by the ADC, thus facilitating continuous operation without dead time. The detector system has a dynamic range of about 80 dB. The customized source consists of eight LED dies attached to a 2 mm × 2 mm substrate and encapsulated in UV-cured epoxy resin. Switching between dies is performed every 20 ms, synchronized to the detector integration period to within 100 ns. The spectroscopic probe has been designed to be fully compatible with simultaneous electroencephalography measurements. Results are presented from measurements on a phantom and a functional brain activation study on an adult volunteer, and the performance of the spectroscopic probe is shown to be very similar to that of a benchtop broadband spectroscopy system. The multi-wavelength capabilities and portability of this spectroscopic probe will create significant opportunities for in vivo studies in a range of clinical and life science applications.
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Affiliation(s)
- Danial Chitnis
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Dimitrios Airantzis
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - David Highton
- Neurocritical Care Unit, National Hospital for Neurology and Neurosurgery, University College London Hospitals, London WC1N 3BG, United Kingdom
| | - Rhys Williams
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Phong Phan
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Vasiliki Giagka
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Samuel Powell
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Robert J Cooper
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Martin Smith
- Neurocritical Care Unit, National Hospital for Neurology and Neurosurgery, University College London Hospitals, London WC1N 3BG, United Kingdom
| | - Clare E Elwell
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Jeremy C Hebden
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Nicholas Everdell
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
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von Lühmann A, Herff C, Heger D, Schultz T. Toward a Wireless Open Source Instrument: Functional Near-infrared Spectroscopy in Mobile Neuroergonomics and BCI Applications. Front Hum Neurosci 2015; 9:617. [PMID: 26617510 PMCID: PMC4641917 DOI: 10.3389/fnhum.2015.00617] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 10/26/2015] [Indexed: 11/13/2022] Open
Abstract
Brain-Computer Interfaces (BCIs) and neuroergonomics research have high requirements regarding robustness and mobility. Additionally, fast applicability and customization are desired. Functional Near-Infrared Spectroscopy (fNIRS) is an increasingly established technology with a potential to satisfy these conditions. EEG acquisition technology, currently one of the main modalities used for mobile brain activity assessment, is widely spread and open for access and thus easily customizable. fNIRS technology on the other hand has either to be bought as a predefined commercial solution or developed from scratch using published literature. To help reducing time and effort of future custom designs for research purposes, we present our approach toward an open source multichannel stand-alone fNIRS instrument for mobile NIRS-based neuroimaging, neuroergonomics and BCI/BMI applications. The instrument is low-cost, miniaturized, wireless and modular and openly documented on www.opennirs.org. It provides features such as scalable channel number, configurable regulated light intensities, programmable gain and lock-in amplification. In this paper, the system concept, hardware, software and mechanical implementation of the lightweight stand-alone instrument are presented and the evaluation and verification results of the instrument's hardware and physiological fNIRS functionality are described. Its capability to measure brain activity is demonstrated by qualitative signal assessments and a quantitative mental arithmetic based BCI study with 12 subjects.
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Affiliation(s)
- Alexander von Lühmann
- Machine Learning Department, Computer Science, Technische Universität Berlin Berlin, Germany ; Institute of Biomedical Engineering, Karlsruhe Institute of Technology Karlsruhe, Germany
| | - Christian Herff
- Cognitive Systems Lab, Karlsruhe Institute of Technology Karlsruhe, Germany
| | - Dominic Heger
- Cognitive Systems Lab, Karlsruhe Institute of Technology Karlsruhe, Germany
| | - Tanja Schultz
- Cognitive Systems Lab, Karlsruhe Institute of Technology Karlsruhe, Germany
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Ono Y, Noah JA, Zhang X, Nomoto Y, Suzuki T, Shimada S, Tachibana A, Bronner S, Hirsch J. Motor learning and modulation of prefrontal cortex: an fNIRS assessment. J Neural Eng 2015; 12:066004. [DOI: 10.1088/1741-2560/12/6/066004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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13
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Funane T. Wearable near-infrared spectroscopy neuroimaging and its applications. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2015:4025-8. [PMID: 26737177 DOI: 10.1109/embc.2015.7319277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Wearable near-infrared spectroscopy (NIRS) systems are expected to be applied in various fields such as health care (medical use), education (teaching), and biofeedback. An investigation on hyperscanning by using NIRS is discussed first, where multiple brains were simultaneously measured for investigating and evaluating important social interactions, such as communication. The relationship between interacting brain activities and performance in cooperation has been demonstrated. An investigation on mood-state measurements in a return-to-work program is next discussed. It has been reported that a specified index calculated using NIRS signals obtained during performance of a working memory task correlated with a mood score. Using this index, the mood states of volunteers who participated in a return-to-work program after psychiatric clinical treatment were monitored. It has been suggested that the relationship between brain activities and subjective assessment of depression mood will be useful for evaluating the recovery stage for return-to-work programs. These techniques open new applications of wearable NIRS systems in mental health care.
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Zhang Q, Ivkovic V, Hu G, Strangman GE. Twenty-four-hour ambulatory recording of cerebral hemodynamics, systemic hemodynamics, electrocardiography, and actigraphy during people's daily activities. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:47003. [PMID: 24781591 DOI: 10.1117/1.jbo.19.4.047003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 03/05/2014] [Indexed: 06/03/2023]
Abstract
The feasibility and utility of wearable 24-h multimodality neuromonitoring during daily activities are demonstrated. We have developed a fourth-generation ambulatory near infrared spectroscopy device, namely NINscan 4. NINscan 4 enables recording of brain function (via cerebral hemodynamics), systemic hemodynamics, electrocardiography, and actigraphy simultaneously and continuously for up to 24 h at 250-Hz sampling rate, during (and with minor restriction to) daily activities. We present initial 24-h human subject test results, with example analysis including (1) comparison of cerebral perfusion and oxygenation changes during wakefulness and sleep over a 24-h period and (2) capturing of hemodynamic changes prior, during and after sudden waken up in the night during sleep. These results demonstrate the first ambulatory 24-h cerebral and systemic hemodynamics monitoring, and its unique advantages including long-term data collection and analysis capability, ability to catch unpredictable transient events during activities of daily living, as well as coregistered multimodality analysis capabilities. These results also demonstrate that NINscan 4's motion artifact at 1-g head movement is smaller than physiological hemodynamic fluctuations during motionless sleep. The broader potential of this technology is also discussed.
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Affiliation(s)
- Quan Zhang
- Massachusetts General Hospital, Harvard Medical School Neural Systems Group, 13th Street, Building 149, Room 2651, Charlestown, Massachusetts 02129bCenter for Space Medicine, Baylor College of Medicine, Houston, Texas
| | - Vladimir Ivkovic
- Massachusetts General Hospital, Harvard Medical School Neural Systems Group, 13th Street, Building 149, Room 2651, Charlestown, Massachusetts 02129
| | - Gang Hu
- Massachusetts General Hospital, Harvard Medical School Neural Systems Group, 13th Street, Building 149, Room 2651, Charlestown, Massachusetts 02129
| | - Gary E Strangman
- Massachusetts General Hospital, Harvard Medical School Neural Systems Group, 13th Street, Building 149, Room 2651, Charlestown, Massachusetts 02129bCenter for Space Medicine, Baylor College of Medicine, Houston, Texas
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Bhutta MR, Hong KS, Kim BM, Hong MJ, Kim YH, Lee SH. Note: three wavelengths near-infrared spectroscopy system for compensating the light absorbance by water. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:026111. [PMID: 24593411 DOI: 10.1063/1.4865124] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Given that approximately 80% of blood is water, we develop a wireless functional near-infrared spectroscopy system that detects not only the concentration changes of oxy- and deoxy-hemoglobin (HbO and HbR) during mental activity but also that of water (H2O). Additionally, it implements a water-absorption correction algorithm that improves the HbO and HbR signal strengths during an arithmetic task. The system comprises a microcontroller, an optical probe, tri-wavelength light emitting diodes, photodiodes, a WiFi communication module, and a battery. System functionality was tested by means of arithmetic-task experiments performed by healthy male subjects.
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Affiliation(s)
- M Raheel Bhutta
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735, South Korea
| | - Keum-Shik Hong
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735, South Korea
| | - Beop-Min Kim
- Department of Biomedical Engineering, Korea University, Seoul 136-703, South Korea
| | - Melissa Jiyoun Hong
- Department of Education Policy and Social Analysis, Columbia University, New York, New York 10027, USA
| | - Yun-Hee Kim
- Department of Physical and Rehabilitation Medicine, Sungkyunkwan University School of Medicine, Seoul 135-710, South Korea
| | - Se-Ho Lee
- Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735, South Korea
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16
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A wearable multi-channel fNIRS system for brain imaging in freely moving subjects. Neuroimage 2013; 85 Pt 1:64-71. [PMID: 23810973 DOI: 10.1016/j.neuroimage.2013.06.062] [Citation(s) in RCA: 235] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 11/21/2022] Open
Abstract
Functional near infrared spectroscopy (fNIRS) is a versatile neuroimaging tool with an increasing acceptance in the neuroimaging community. While often lauded for its portability, most of the fNIRS setups employed in neuroscientific research still impose usage in a laboratory environment. We present a wearable, multi-channel fNIRS imaging system for functional brain imaging in unrestrained settings. The system operates without optical fiber bundles, using eight dual wavelength light emitting diodes and eight electro-optical sensors, which can be placed freely on the subject's head for direct illumination and detection. Its performance is tested on N=8 subjects in a motor execution paradigm performed under three different exercising conditions: (i) during outdoor bicycle riding, (ii) while pedaling on a stationary training bicycle, and (iii) sitting still on the training bicycle. Following left hand gripping, we observe a significant decrease in the deoxyhemoglobin concentration over the contralateral motor cortex in all three conditions. A significant task-related ΔHbO2 increase was seen for the non-pedaling condition. Although the gross movements involved in pedaling and steering a bike induced more motion artifacts than carrying out the same task while sitting still, we found no significant differences in the shape or amplitude of the HbR time courses for outdoor or indoor cycling and sitting still. We demonstrate the general feasibility of using wearable multi-channel NIRS during strenuous exercise in natural, unrestrained settings and discuss the origins and effects of data artifacts. We provide quantitative guidelines for taking condition-dependent signal quality into account to allow the comparison of data across various levels of physical exercise. To the best of our knowledge, this is the first demonstration of functional NIRS brain imaging during an outdoor activity in a real life situation in humans.
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Everdell NL, Airantzis D, Kolvya C, Suzuki T, Elwell CE. A portable wireless near-infrared spatially resolved spectroscopy system for use on brain and muscle. Med Eng Phys 2013; 35:1692-7. [PMID: 23706504 DOI: 10.1016/j.medengphy.2013.04.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 10/26/2022]
Abstract
We have designed, built and successfully tested a prototype portable and wireless near-infrared spectroscopy system. It takes forward the well-established series of NIRO spectroscopy instruments made by Hamamatsu Photonics (Hamamatsu City, Japan). It uses an identical optical probe, and has a data acquisition rate of 10 Hz. It illuminates the tissue with laser diode sources at 3 wavelengths of 775, 810 and 850 nm, and detects the reflected light with 2 silicon photodiode detectors at 2 different separations, enabling spatially resolved spectroscopy to be performed. We have tested it with both in vitro and in vivo experiments to establish its basic functionality for use in studies of both brain and muscle.
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Affiliation(s)
- N L Everdell
- Department of Medical Physics and Bioengineering, University College London, Gower Street, London, WC1E 6BT, UK.
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