Search results for " sensitivity"
showing 10 items of 947 documents
Reliability in perimetric multichannel contrast sensitivity measurements
2014
Background: In this study, the reliability of perimetric contrast sensitivity measurements favouring the achromatic, the red-green and the blue-yellow post-receptorial mechanisms was analysed. Methods: A new technique, multichannel ATD perimetry, provides spatial and temporal stimuli favouring the detection by an achromatic mechanism (A), from a magno or parvocellular origin or by a red-green (RG) chromatic mechanism, with a parvocellular origin or a blue-yellow (BY) mechanism, with a koniocellular origin. The repeatability and reproducibility of contrast sensitivity measurements with these stimuli were studied in a group of 40 healthy subjects. The analysis was carried out on 21 testing po…
Pulpal ischemia in man: effects on detection threshold, A-delta neural response and sharp dental pain
1999
— Preferential blocks of peripheral nerves have shown that myelinated nerves are more susceptible to local compression and less resistent to asphyxia than unmyelinated fibers. Since two groups of functionally different nociceptors exist in the dental pulp, it is of theoretical and clinical interest to determine the influence of ischemia on the sensitivity of human dental pulp, using standard means for testing tooth vitality and at the same time investigating the intensity coding in one pathway of the afferent trigeminal system. Adrenaline was used to study the differential effect of adrenaline-induced ischemia on intradental A-delta nerve activity (INA) and the concomitant sharp pain, as we…
Surface Lightness Influences Perceived Room Height
2010
Surprisingly little scientific research has been conducted on the effects of colour and lightness on the perception of spaciousness. Practitioners and architects typically suggest that a room's ceiling appears higher when it is painted lighter than the walls, while darker ceilings appear lower. Employing a virtual reality setting, we studied the effects of the lightness of different room surfaces on perceived height in two psychophysical experiments. Observers judged the height of rooms varying in physical height as well as in the lightness of ceiling, floor, and walls. Experiment 1 showed the expected increase of perceived height with increases in ceiling lightness. Unexpectedly, the perce…
Mother-infant interaction and children's socio-emotional development with high- and low-risk mothers.
2008
Charting the dynamic character of mother-infant interaction requires using observational systems of sequential coding in real time. A longitudinal study was designed to approach maternal sensitivity in a more complex way using sequential analysis. The study was conducted with 20 high- and 20 low-risk mothers and their infants (aged: 3, 12 and 15 months) to examine the relation among mothers' risk status for physical abuse and their maternal interactive profiles, using micro-social sequential analyses, and the subsequent quality of attachment developed by their children at 15 months of age. Results showed significantly different timings in maternal responses in high- and low-risk groups, tha…
Visual quality comparison of conventional and Hole-Visian implantable collamer lens at different degrees of decentering
2013
Purpose To compare the visual quality of implantable collamer lens (ICL) with and without central hole (Hole ICL and conventional ICL) at different degrees of decentering. Methods An adaptive optics visual simulator (crx1, Imagine Eyes, Orsay, France) was used to simulate the –3, –6 and –12 dioptres (D) conventional and Hole ICLs in three conditions: centred and decentred 0.3 and 0.6 mm. Visual acuity (VA) at high-contrast, medium-contrast and low-contrast and contrast sensitivity (CS) were measured in 15 observers for 3 and 4.5 mm pupils. Results No statistically significant differences in VA and CS were found between conventional and Hole ICLs for any ICL powers and pupil sizes evaluated …
Optical and Visual Simulation of Standard and Modified Spherical Aberration Implantable Collamer Lens Post Myopic LASIK Surgery
2013
To evaluate the visual quality achieved in patients undergoing standard or modified implantable Collamer lens (ICL) to correct residual myopic error after laser-assisted in situ keratomileusis (LASIK) surgery.The adaptive optics visual simulator was used to simulate LASIK surgery of moderate and high myopia with a myopic regression corrected by a standard and modified ICL. Visual acuity (VA) and contrast sensitivity (CS) were measured in 14 subjects at 3- and 4.5-mm pupil. Point spread function and simulated retinal images were calculated.Comparing LASIK plus standard ICL and LASIK plus modified ICL simulations, for moderate myopia, VA improvement was less than 1 line in all VA contrasts an…
Autonomic cardiac regulation in obstructive sleep apnea syndrome: evidence from spontaneous baroreflex analysis during sleep
1997
Objective. To assess spontaneous baroreceptor-heart rate reflex sensitivity during sleep in patients with obstructive sleep apnea syndrome, a condition associated with increased cardiovascular morbidity and mortality and characterized by marked sympathetic activation, which is believed to originate from hypoxic chemoreceptor stimulation, although little is known of other possible mechanisms such as baroreflex impairment. Design and methods. In 11 patients with severe obstructive sleep apnea syndrome (mean ± SD age 46.8 ± 8.1 years, apnea/hypopnea index 67.9 ± 19.1 h), who were normotensive or borderline hypertensive during wakefulness by clinic blood pressure measurements, finger blood pres…
Volatile organic compounds (VOCs) in exhaled breath as a marker of hypoxia in multiple chemical sensitivity
2021
Abstract In the history of diagnostics, breath analysis was one of the first method used until the breakthrough of biochemical testing technology. Today, breath analysis has made a comeback with the development of gas analyzers and e‐noses, demonstrating its power in its applicability for diagnosing a wide range of diseases. The physical basis of multiple chemical sensitivity (MCS), an emerging environmental disease, is difficult to understand because it is based on the scenario of chronic hypoxia, with a complex of chemical compounds that trigger the syndrome and result in multiple symptoms. The aim of this study was to investigate MCS by analyzing exhaled volatile organic compounds (VOCs)…
Crystalens HD Intraocular Lens Analysis Using an Adaptive Optics Visual Simulator
2013
PURPOSE To compare visual and optical quality of the Crystalens HD intraocular lens (IOL) with that of a monofocal IOL. METHODS The wavefront aberration patterns of the monocular Akreos Adapt AO IOL and the single-optic accommodating Crystalens HD IOL were measured in a model eye. The Crystalens IOL was measured in its nonaccommodative state and then, after flexing the haptic to produce 1.4 mm of movement, in its accommodative state. Using an adaptive optics system, subjects' aberrations were removed and replaced with those of pseudophakes viewing with either lens. Monocular distance visual acuity (DVA) at high (100%), medium (50%), and low (10%) contrast and contrast sensitivity (CS) were …
Impact of antifungal prophylaxis on colonization and azole susceptibility of Candida species.
2009
ABSTRACT Two large studies compared posaconazole and fluconazole or itraconazole for prophylaxis in subjects undergoing allogeneic hematopoietic stem cell transplantation or subjects with acute myelogenous leukemia. To assess the impact of prophylaxis on colonization and the development of resistance in Saccharomyces yeasts, identification and susceptibility testing were performed with yeasts cultured at regular intervals from mouth, throat, and stool samples. Prior to therapy, 34 to 50% of the subjects were colonized with yeasts. For all three drugs, the number of positive Candida albicans cultures decreased during drug therapy. In contrast, the proportion of subjects with positive C. glab…