Search results for "ear-infrared spectroscopy"

En-Face differential absorption optical coherence tomography with gold nanorods as the contrast agent

2008

A new variety of nanoparticles showing unique and characteristic optical properties, appeals for its use as contrast agents in medical imaging. Gold nanospheres, nanorods and nanoshells with a silica core are new forms of promising contrast agents which can be tuned to specific absorption or scattering characteristics within the near-infrared (NIR) spectrum ranging from 650 - 1300 nm. They have the ability to be used for both image enhancement and as photosensitive markers due to their well designable scattering and absorption properties. Furthermore, their strong optical absorption permits treatment of malignant cells by photoablation processes, induced when heating them with a matched lig…

Comparison of a near-infrared reflectance spectroscopy system and skin conductance measurements for in vivo estimation of skin hydration: a clinical …

2017

Diffuse reflectance spectroscopy system was developed for estimation of skin hydration in the near-infrared spectral range of 900-1700 nm. Experimental setup consisted of a near-infrared spectrometer, Y-type fiber optics probe with 1 detection and 6 illumination fibers, halogen-tungsten light source and a PC. By analyzing diffuse reflectance spectrum, a parameter representing skin hydration by performing baseline correction and calculating the area under the 1450 nm water absorption maximum is proposed. A clinical study was performed acquiring data of skin hydration of 39 patients' forearm skin. Results of the developed system are compared to results obtained by a commercial device based on…

Motor Cortex Function in Fibromyalgia: A Study by Functional Near-Infrared Spectroscopy

2019

Previous studies indicated changes of motor cortex excitability in fibromyalgia (FM) patients and the positive results of transcranial stimulation techniques. The present study aimed to explore the metabolism of motor cortex in FM patients, in resting state and during slow and fast finger tapping, using functional Near-Infrared Spectroscopy (fNIRS), an optical method which detects in real time the metabolism changes in the cortical tissue. We studied 24 FM patients and 24 healthy subjects. We found a significant slowness of motor speed in FM patients compared to controls. During resting state and slow movement conditions, the metabolism of the motor areas was similar between groups. The oxy…

Challenges in the use of Near Infrared Spectroscopy for improving wood quality: A review

2018

Aims of study: Forestry-related companies require quality monitoring methods capable to pass a large number of samples. This review paper is dealing with the utilization of near infrared (NIR) technique for wood analysis.Area of study: We have a global point of view for NIR applications and characterization of different kind of wood species is considered.Material and methods: NIR spectroscopy is a fast, non-destructive technique, applicable to any biological material, demanding little or no sample preparation. NIR spectroscopy and multivariate analysis serve well in laboratories where the conditions are controlled. The main challenges to NIR spectroscopy technique in field conditions are mo…

Functional Near Infrared Spectroscopy System Validation for Simultaneous EEG-FNIRS Measurements

2019

Functional near-infrared spectroscopy (fNIRS) applied to brain monitoring has been gaining increasing relevance in the last years due to its not invasive nature and the capability to work in combination with other well–known techniques such as the EEG. The possible use cases span from neural-rehabilitation to early diagnosis of some neural diseases. In this work a wireline FPGA–based fNIRS system, that use SiPM sensors and dual-wavelength LED sources, has been designed and validated to work with a commercial EEG machine without reciprocal interference.

Muscle Oxygen Delivery in the Forearm and in the Vastus Lateralis Muscles in Response to Resistance Exercise: A Comparison Between Nepalese Porters a…

2020

Altitude ascending represents an intriguing experimental model reproducing physiological and pathophysiological conditions sharing hypoxemia as the denominator. The aim of the present study was to investigate fractional oxygen extraction and blood dynamics in response to hypobaric hypoxia and to acute resistance exercises, taking into account several factors including different ethnic origin and muscle groups. As part of the “Kanchenjunga Exploration & Physiology” project, six Italian trekkers and six Nepalese porters took part in a high altitude trek in the Himalayas. The measurements were carried out at low (1,450 m) and high altitude (HA; 4,780 m). Near-infrared spectroscopy (NIRS)-d…

Water detection in skin by dual-band photodiodes

2013

Purpose of this study was to develop a simple model for possibilities to detect water in skin by diffuse reflectance spectra. The model is based on comparison of diffuse reflectance spectra when illuminating water sample with LEDs of different wavelengths (1200 nm, and 1450 nm). The illumination LEDs were chosen due to water absorption differences in near-infrared spectral range. For detection, dual-band photodiode DSD2 by Thorlabs was used. Due to differences of water absorption at different wavelengths in the near-infrared spectral region, this correlation could be used for mapping of water content in skin or, in other words, determine relative moisture level in skin. Simple experimental …

<title>Near-infrared spectroscopy (NIRS) as a diagnostic tool in patients with suspected stroke or traumatic brain injury</title>

2001

Near-Infrared Spectroscopy (NIRS) as a diagnostic tool in patients with suspected stroke or brain injury S. Goldberg, C. Lott, M. Ostermeyer, H.-J. Hennes Absorption of Near-Infrared (NIR) light in the brain is mainly caused by hemoglobin. Superficial intracranial hematoma with a higher concentration of hemoglobin causes a higher absorption in NIRS. The existence of hemorrhage can be demonstrated by the difference of optical density, comparing identical measuring points at both hemispheres of the brain: absorption of NIR light is greater at the side of the hemorrhage, causing less reflection in NIRS. In a prospective, blinded study, 100 patients who were scheduled for CCT-scan for brain inj…

<title>Follow-up in patients with subdural haematomas using near-infrared spectroscopy (NIRS)</title>

1998

Secondary haemorrhage is an important cause of brain injury following initial therapy of subdural haematoma (SDH). Early identification and treatment of secondary haemorrhage improves neurologic outcome. Near infrared light at a wavelength of 760 nm shows a high absorption for haemoglobin. The difference in absorbance of light ((Delta) OD) at the wavelength of 760 nm between both hemispheres is measured to detect SDH. We have prospectively studied 20 patients with the CT diagnosis of SDH using near infrared spectroscopy (NIRS). Unilateral subdural haematomas were detected by NIRS in 15 out of 16 patients. Bilateral SDH were detected in 2 out of 3 patients. The median of (Delta) OD was reduc…

2019

Gait and balance impairments are frequently considered as the most significant concerns among individuals suffering from neurological diseases. Robot-assisted gait training (RAGT) has shown to be a promising neurorehabilitation intervention to improve gait recovery in patients following stroke or brain injury by potentially initiating neuroplastic changes. However, the neurophysiological processes underlying gait recovery through RAGT remain poorly understood. As non-invasive, portable neuroimaging techniques, electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) provide new insights regarding the neurophysiological processes occurring during RAGT by measuring diffe…