Search results for " a-wave"

showing 3 items of 3 documents

An approach based on wavelet analysis for feature extraction in the electroretinogram

2011

Most biomedical signals are non-stationary. The knowledge of their frequency content and temporal distribution is then useful in a clinical context. The wavelet analysis is appropriate to achieve this task. The present paper uses this method to reveal hidden characteristics and anomalies of the human a-wave, an important component of the electroretinogram since it is a measure of the functional integrity of the photoreceptors. We here analyse the time–frequency features of the a-wave both in normal subjects and in patients affected by Achromatopsia, a pathology disturbing the functionality of the cones. The results indicate the presence of two or three stable frequencies that, in the pathol…

Electroretinogram a-Wave Photoreceptoral response Achromatopsia Wavelet analysisSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)
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A study of the human rod and cone electroretinogram a-wave component

2009

The study of the electrical response of the retina to a luminous stimulus is one of the main fields of research in ocular electrophysiology. The features of the first component (a-wave) of the retinal response reflect the functional integrity of the two populations of photoreceptors: rods and cones. We fit the a-wave for pathological subjects with functions that account for possible mechanisms governing the kinetics of the photoreceptors. The paper extends a previous analysis, carried out for normal subjects, in which both populations are active, to patients affected by two particular diseases that reduce the working populations to only one. The pathologies investigated are Achromatopsia, a…

Statistics and ProbabilityCongenital stationary night blindnessRetinaAchromatopsiagenetic structuresbusiness.industryStatistical and Nonlinear PhysicsRetinalBiologyStimulus (physiology)medicine.diseaseSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)electroretinogram a-wavechemistry.chemical_compoundElectrophysiologyFunctional integrityOpticsmedicine.anatomical_structurechemistrymedicinesense organsStatistics Probability and UncertaintybusinessNeuroscienceVisual phototransduction
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ERG signal analysis using wavelet transform

2009

The wavelet analysis is a powerful tool for analyzing and detecting features of signals characterized by time-dependent statistical properties, as biomedical signals. The identification and the analysis of the components of these signals in the time-frequency domain, give meaningful information about the physiological mechanisms that govern them. This article presents the results of the wavelet analysis applied to the a-wave component of the human electroretinogram. In order to deepen and improve our knowledge about the behavior of the early photoreceptoral response, including the possible activation of interactions and correlations among the photoreceptors, we have detected and identified …

Statistics and ProbabilitySignal processingComputer scienceApplied MathematicsWavelet AnalysisMexican hat waveletWavelet transformLuminanceRetinaSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)Electroretinogram – a-wave – Photoreceptoral response – Wavelet analysis – Mexican hat waveletRange (mathematics)Identification (information)WaveletOrder (biology)ElectroretinographyHumansPhotoreceptor CellsBiological systemPhotic StimulationEcology Evolution Behavior and SystematicsTheory in Biosciences
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