Papers by Antonio Fratini
Many studies have accounted for whole body vibration effects in the fields of exercise physiology... more Many studies have accounted for whole body vibration effects in the fields of exercise physiology, sport and rehabilitation medicine. Generally, surface EMG is utilized to assess muscular activity during the treatment; however, large motion artifacts appear superimposed to the raw signal, making sEMG recording not suitable before any artifact filtering. Sharp notch filters, centered at vibration frequency and at its superior harmonics, have been used in previous studies, to remove the artifacts. [6, 10] However, to get rid of those artifacts some true EMG signal is lost. The purpose of this study was to reproduce the effect of motor-unit synchronization on a simulated surface EMG during vibratory stimulation. In addition, authors mean to evaluate the EMG power percentage in those bands in which are also typically located motion artifact components. Model characteristics were defined to take into account two main aspect: the muscle MUs discharge behavior and the triggering effects that appear during local vibratory stimulation. [7] Inter-pulse-interval, was characterized by a polimodal distribution related to the MU discharge frequency (IPI 55-80ms, σ=12ms) and to the correlation with the vibration period within the range of ±2 ms due to vibration stimulus. [1, 7] The signals were simulated using different stimulation frequencies from 30 to 70 Hz. The percentage of the total simulated EMG power within narrow bands centered at the stimulation frequency and its superior harmonics (± 1 Hz) resulted on average about 8% (± 2.85) of the total EMG power. However, the artifact in those bands may contain more than 40% of the total power of the total signal. [6] Our preliminary results suggest that the analysis of the muscular activity of muscle based on raw sEMG recordings and RMS evaluation, if not processed during vibratory stimulation may lead to a serious overestimation of muscular response.
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This study extends a previous research concerning intervertebral motion registration by means of ... more This study extends a previous research concerning intervertebral motion registration by means of 2D dynamic fluoroscopy to obtain a more comprehensive 3D description of vertebral kinematics. The problem of estimating the 3D rigid pose of a CT volume of a vertebra from its 2D X-ray fluoroscopy projection is addressed. 2D-3D registration is obtained maximising a measure of similarity between Digitally Reconstructed Radiographs (obtained from the CT volume) and real fluoroscopic projection. X-ray energy correction was performed. To assess the method a calibration model was realised a sheep dry vertebra was rigidly fixed to a frame of reference including metallic markers. Accurate measurement of 3D orientation was obtained via single-camera calibration of the markers and held as true 3D vertebra position; then, vertebra 3D pose was estimated and results compared. Error analysis revealed accuracy of the order of 0.1 degree for the rotation angles of about 1?mm for displacements parallel to the fluoroscopic plane, and of order of 10?mm for the orthogonal displacement.
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Elsevier eBooks, 2023
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EURASIP Journal on Advances in Signal Processing, Jun 30, 2009
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Arquivos Brasileiros de Oftalmologia, 2014
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Frontiers in Human Neuroscience
IntroductionThere is accumulating evidence that many pathological conditions affecting human bala... more IntroductionThere is accumulating evidence that many pathological conditions affecting human balance are consequence of postural control (PC) failure or overstimulation such as in motion sickness. Our research shows the potential of using the response to a complex postural control task to assess patients with early-stage Parkinson's Disease (PD).MethodsWe developed a unique measurement model, where the PC task is triggered by a moving platform in a virtual reality environment while simultaneously recording EEG, EMG and CoP signals. This novel paradigm of assessment is called BioVRSea. We studied the interplay between biosignals and their differences in healthy subjects and with early-stage PD.ResultsDespite the limited number of subjects (29 healthy and nine PD) the results of our work show significant differences in several biosignals features, demonstrating that the combined output of posturography, muscle activation and cortical response is capable of distinguishing healthy f...
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Many cervical spine pathologies involve degeneration of the stabilizing mechanisms of vertebrae s... more Many cervical spine pathologies involve degeneration of the stabilizing mechanisms of vertebrae segments and often cause pain. Abnormal intervertebral motion is an indication for surgery. Currently, spinal fusion surgery is widely adopted to fix the instable vertebral segments but recently, disk arthroplasty is more and more adopted as an alternative to restore normal kinematics and biomechanics of the sick segment and to reduce development of symptomatic adjacent-level degeneration. This study aims to measure intervertebral kinematics by means of image processing of X-ray fluoroscopy videos, which are able to screen patient's neck spontaneous movements of flexion-extension. Vertebrae trajectories are estimated by using image template matching techniques. Then, continuous-time intervertebral kinematics is computed by using spline interpolation. The results, obtained by using real fluoroscopy videos, reveal the possibility of obtaining in vivo information about the continuous evolution of motion of the implanted prosthesis and adjacent segments.
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Research Square (Research Square), Nov 15, 2021
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bioRxiv (Cold Spring Harbor Laboratory), Sep 1, 2021
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Along with other diseases that can affect binocular vision, reducing the visual quality of a subj... more Along with other diseases that can affect binocular vision, reducing the visual quality of a subject, Congenital Nystagmus (CN) is of peculiar interest. CN is an ocular-motor disorder characterized by involuntary, conjugated ocular oscillations and, while identified more than forty years ago, its pathogenesis is still under investigation. This kind of nystagmus is termed congenital (or infantile) since it could be present at birth or it can arise in the first months of life. The majority of CN patients show a considerable decrease of their visual acuity: image fixation on the retina is disturbed by nystagmus continuous oscillations, mainly horizontal. However, the image of a given target can still be stable during short periods in which eye velocity slows down while the target image is placed onto the fovea (called foveation intervals). To quantify the extent of nystagmus, eye movement recordings are routinely employed, allowing physicians to extract and analyze nystagmus main features such as waveform shape, amplitude and frequency. Use of eye movement recording, opportunely processed, allows computing "estimated visual acuity" predictors, which are analytical functions that estimate expected visual acuity using signal features such as foveation time and foveation position variability. Hence, it is fundamental to develop robust and accurate methods to measure both those parameters in order to obtain reliable values from the predictors. In this chapter the current methods to record eye movements in subjects with congenital nystagmus will be discussed and the present techniques to accurately compute foveation time and eye position will be presented. This study aims to disclose new methodologies in congenital nystagmus eye movements analysis, in order to identify nystagmus cycles and to evaluate foveation time, reducing the influence of repositioning saccades and data noise on the critical parameters of the estimation functions. Use of those functions extends the information acquired with typical visual acuity measurement (e.g., Landolt C test) and could be a support for treatment planning or therapy monitoring. © 2010 by Nova Science Publishers, Inc. All rights reserved.
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IFMBE proceedings, 2009
Whole body vibration (WBV) aims to mechanically activate muscles by eliciting stretch reflexes. M... more Whole body vibration (WBV) aims to mechanically activate muscles by eliciting stretch reflexes. Mechanical vibrations are usually transmitted to the patient body standing on a oscillating plate. WBV is now more and more utilized not only for fitness but also in physical therapy, rehabilitation and in sport medicine. Effects depend on intensity, direction and frequency of vibration; however, the training
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IFMBE proceedings, 2009
Congenital nystagmus (CN) is an ocular-motor disorder characterised by involuntary, conjugated oc... more Congenital nystagmus (CN) is an ocular-motor disorder characterised by involuntary, conjugated ocular oscillations and its pathogenesis is still under investigation. This kind of nystagmus is termed congenital (or infantile) since it could be present at birth or it can arise in the first months of life. Most of CN patients show a considerable decrease of their visual acuity: image fixation
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IFMBE proceedings, 2009
A valuable alternative to US cardiotocography, for fetal surveillance, can be offered by phonocar... more A valuable alternative to US cardiotocography, for fetal surveillance, can be offered by phonocardiography, a passive and low cost acoustic recording of fetal heart sounds. A crucial point is the exact recognizing of the fetal heart sounds, associated to each fetal heart beat, and then the estimation of FHR signal. In this work, software for FHR assessment from phonocardiographic signals
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Springer eBooks, Oct 19, 2007
Whole Body Vibration training is more and more utilized in sport medicine to enhance athletic per... more Whole Body Vibration training is more and more utilized in sport medicine to enhance athletic performance and training; recently, vibration treatment is being also used for therapy and rehabilitation for patients affected by different pathologies. It is also worth mention that ...
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ABSTRACT Monitoring foetal health is a very important task in clinical practice to appropriately ... more ABSTRACT Monitoring foetal health is a very important task in clinical practice to appropriately plan pregnancy management and delivery. In the third trimester of pregnancy, cardiotocography (CTG) is the most employed diagnostic technique. In CTG monitoring, foetal heart rate (FHR) and uterine contractions (UC) signals are simultaneously recorded and analysed in order to ascertain foetal health. In particular, indexes related to variability of FHR (FHRV) are usually utilised, which enrich the information provided by CTG. FHRV is acknowledged as an important parameter for the evaluation of foetal well-being. Moreover, HR fluctuations analysis allows for a non-invasive estimation of both the sympathetic and parasympathetic branches of the autonomic nervous system (ANS). Hence, one can observe all of the FHRV frequency components and their modifications by applying a time-frequency approach. Time dependent spectrum analysis, in fact, allows for a distinct understanding of the spectral components during dynamic or active foetal states and their change over time. This work aims to show some specific very useful examples of FHRV time-frequency analysis purposes. Furthermore, the necessity of data pre-processing before FHRV signal processing is considered. The obtained results showed important modifications of power spectral density (PSD) correlated to different foetal conditions. Hence they confirmed that FHRV provides extremely significant information concerning the cardiac and ANS activities. Our results showed also that some important clinical parameters related to PSD of FHRV (such as sympatho-vagal balance) can be erroneously estimated due to a not appropriate storage rate of CTG data.
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Biomedical Engineering Online, 2013
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Papers by Antonio Fratini