We present a frequency-domain optical method for real-time noninvasive measurement of absolute tissue and arterial saturation. This method is based on quantitative measurement of the tissue absorption spectrum (for tissue saturation) and of the amplitude of the arterial-pulsation-induced absorption oscillations (for arterial saturation) at eight wavelengths in the range 633-841 nm. We report re...

An analysis is presented for the transfer functions of a particular pulse-width modulator and power switch subsystem that has been widely used in practical switching-mode d-c regulator systems. The switch and filter are in a "buck" configuration, and the switch is driven by a con­ stant-frequency variable duty-ratio push-pull magnetic modulator employing square-loop cores. The two transfer func...

The advocated SphygmoCor procedure uses a radial-to-aorta transfer function with calibration on brachial instead of radial artery pressure to assess the central pulse pressure. We compared these values with carotid artery pulse pressures obtained from a validated calibration method, assuming mean minus diastolic blood pressure constant throughout the large artery tree. From 44 healthy subjects ...

1. Obstructive sleep apnoea and its variants often provoke hundreds of short arousals that lead to the most important symptom, disabling hypersomnolence. The measurement of sleep in these conditions requires the documentation of these short arousals and this is conventionally done by manual inspection of the sleeping EEG, a laborious procedure. 2. Other markers of 'arousal', that are easier to ...

© 2011 A. Maziar Zafari et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution 3.0 Unported License ( http://creativecommons.org/licenses/by/3.0/), which permits distribution of derivative works, distribution, public display, and publicly performance, making multiple copies, provided the original work is properly cited. This license requires copyri...

introduction: the primary somatosensory cortex has an important role in nociceptive sensory-discriminative processing. altered peripheral inputs produced by deafferentation or by long-term changes in levels of afferent stimulation can result in plasticity of cortex. capsaicin-induced depletion of c-fiber afferents results in plasticity of the somatosensory system. plasticity includes short-term...

Pressure wave reflection in the upper limb causes amplification of the arterial pulse so that radial systolic and pulse pressures are greater than in the ascending aorta. Wave transmission properties in the upper limbs (in contrast to the descending aorta and lower limbs) change little with age, disease, and drug therapy in adult humans. Such consistency has led to use of a generalized transfer...

This study investigated the effect of five speech processing parameters, currently employed in cochlear implant processors, on speech understanding. Experiment 1 examined speech recognition as a function of stimulation rate in six Med-E1/CIS-Link cochlear implant listeners. Results showed that higher stimulation rates (2100 pulses/s) produced a significantly higher performance on word and conso...

Background: Pulse Oximeter monitoring has become so common over previous decades that in some health care units, blood oxygen level is now considered as the fifth vital sign. However, it seems there is still some lack of knowledge and/or experience among medical staff operating pulse oximeter and interpreting its results. The aim of this study was to investigate and compare the knowledge on Pul...