Search results for "Wave"
showing 10 items of 6009 documents
Comparing extracorporeal shock wave lithotripsy and ureteroscopy laser lithotripsy for treatment of urinary stones smaller than 2 cm: a cost-utility …
2021
[EN] Purpose To analyze the efficiency and cost-utility profile of ureteroscopy versus shock wave lithotripsy for treatment of reno-ureteral stones smaller than 2 cm. Methods Patients treated for urinary stones smaller than 2 cm were included in this study (n = 750) and divided into two groups based on technique of treatment. To assess the cost-utility profile a sample of 48 patients (50% of each group) was evaluated. Quality of life survey (Euroqol 5QD-3L) before-after treatment was applied, Markov model was designed to calculate quality of life in each status of the patients (stone or stone-free with and without double-J stent) and to estimate the incremental cost-utility. Monte carlo sim…
Plasticity of brain wave network interactions and evolution across physiologic states
2015
Neural plasticity transcends a range of spatio-temporal scales and serves as the basis of various brain activities and physiologic functions. At the microscopic level, it enables the emergence of brain waves with complex temporal dynamics. At the macroscopic level, presence and dominance of specific brain waves is associated with important brain functions. The role of neural plasticity at different levels in generating distinct brain rhythms and how brain rhythms communicate with each other across brain areas to generate physiologic states and functions remains not understood. Here we perform an empirical exploration of neural plasticity at the level of brain wave network interactions repre…
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…
On-eye optical quality of daily disposable contact lenses for different wearing times
2012
Purpose To quantify the optical quality of various daily disposable contact lenses in vivo and to ascertain its variation in terms of wearing time by means of objective non-invasive determination of wavefront patterns. Methods The crx1 adaptive-optics system was used to measure the wavefront aberrations in 15 myopic eyes before and at 2-h intervals after contact lens fitting, over a 12-h wearing period. Seven types of contact lenses having different material, water content and lens design were evaluated in this study: Dailies Total1, Dailies AquaComfort Plus, Proclear 1 Day, 1-Day Acuvue TruEye, 1-Day Acuvue moist, SofLens daily disposable and Clariti 1-Day. The aberration data were analyse…
Nonlinear EEG dynamics during sleep in depression and schizophrenia.
1994
The article deals with the question, whether nonlinear analysis of the sleep EEG may give clues to understanding of disturbed information processing in psychiatric diseases. We point out how the nonlinear approach to EEG dynamics is motivated and review recent investigations concerning nonlinear dynamical properties of physiological systems. We present calculations of the correlation dimension D2 and the principal Lyapunov-exponent lambda 1 for sleep EEG data from 9 depressive and 11 schizophrenic inpatients compared to healthy controls. Combining the findings for D2 and lambda 1 our results point to altered nonlinear brain dynamics mainly during slow wave sleep in depression and during REM…
Estimation of the dimensionality of sleep-EEG data in schizophrenics
1993
Deterministic chaos could be regarded as a healthy flexibility of the human brain necessary for correct neuronal operations. Several investigations have demonstrated that in healthy subjects the dimensionality of REM sleep is much higher than that of slow wave sleep (SWS). We investigated the sleep-EEG of schizophrenic patients with methods from nonlinear system theory in order to estimate the dynamic properties of CNS. We hypothesized that schizophrenics would reveal alterations of their dynamic EEG features indicating impaired information processing. In 11 schizophrenic patients, the EEG's dimensionality during sleep stages II and REM was reduced. We suggest that such lower dimensional ch…
An analysis of the brain's transfer properties in schizophrenia: Amplitude frequency characteristics and evoked potentials during sleep
1998
Background: Classical analysis of spontaneous sleep electroencephalogram (EEG) in schizophrenia commonly reveals alterations of sleep continuity, number of awakenings, slow-wave sleep (SWS), and REM sleep compared to healthy controls; however, conventional analysis cannot help understand dynamic differences of the sleep EEG during different sleep stages. Methods: We measured late components of auditory evoked potentials (AEPs) and visual evoked potentials (VEPs) during different sleep stages of 11 schizophrenic inpatients and in a sex- and age-matched control group from scalp positions FZ, CZ, and PZ. According to linear system theory, we then computed the amplitude-frequency characteristic…
Analysis of F response in upper motoneurone lesions
2009
The F response can provide a measure of motoneurone excitability (MNE) and so it may be used to investigate upper motoneurone disorders. This report studies the F-wave configuration in patients with stroke to evaluate the changes of the central excitability of the motoneurones at different times after an acute cerebral insult. Various parameters of the F response, including amplitude (absolute and F%/M), duration, and persistence have been determined in 26 patients with unilateral hemiplegia and in 32 healthy subjects of both sexes in the same age range. The investigation was carried out applying a series of 20 supramaximal stimuli at 0.5 Hz on tibial and ulnar nerves bilaterally. In all pa…
F-Wave study in patients with chronic renal failure on regular haemodialysis
1986
Motor nerve conduction along the entire length of ulnar and tibialis posterior nerves was studied in 30 uraemic patients and in 20 control subjects. The M and F latencies, MNCV (between the stimulus sites), FWCV (between the spinal cord and the stimulus sites) and F-ratio (conduction time ratio of proximal to distal segment) were assessed to evaluate the conduction in the proximal versus the distal nerve segment. In the uraemic patients, the slowing of nerve conduction involved both segments of the tested nerves to the same extent. In fact, the F-ratio did not show any significant difference between the two groups; in only one patient was its value lower than the normal limit in the tibiali…
Arterial stiffness indexes in acute ischemic stroke: Relationship with stroke subtype
2010
INTRODUCTION: No study has evaluated both arterial stiffness indexes (PWV and Aix) in patients with an acute cerebrovascular event. The aim of our study was to evaluate arterial stiffness indexes in subjects with acute ischemic stroke and to evaluate the relationship between these indexes and other clinical and laboratory variables. MATERIALS AND METHODS: We enrolled all consecutive patients with a diagnosis of acute ischemic stroke admitted to the Internal Medicine Department at the University of Palermo between November 2006 and January 2009, and hospitalized control patients without a diagnosis of acute ischemic stroke. The type of acute ischemic stroke was classified according to the TO…