1,584 research outputs found
3D Transformer based on deformable patch location for differential diagnosis between Alzheimer's disease and Frontotemporal dementia
Alzheimer's disease and Frontotemporal dementia are common types of
neurodegenerative disorders that present overlapping clinical symptoms, making
their differential diagnosis very challenging. Numerous efforts have been done
for the diagnosis of each disease but the problem of multi-class differential
diagnosis has not been actively explored. In recent years, transformer-based
models have demonstrated remarkable success in various computer vision tasks.
However, their use in disease diagnostic is uncommon due to the limited amount
of 3D medical data given the large size of such models. In this paper, we
present a novel 3D transformer-based architecture using a deformable patch
location module to improve the differential diagnosis of Alzheimer's disease
and Frontotemporal dementia. Moreover, to overcome the problem of data
scarcity, we propose an efficient combination of various data augmentation
techniques, adapted for training transformer-based models on 3D structural
magnetic resonance imaging data. Finally, we propose to combine our
transformer-based model with a traditional machine learning model using brain
structure volumes to better exploit the available data. Our experiments
demonstrate the effectiveness of the proposed approach, showing competitive
results compared to state-of-the-art methods. Moreover, the deformable patch
locations can be visualized, revealing the most relevant brain regions used to
establish the diagnosis of each disease
Deep Grading based on Collective Artificial Intelligence for AD Diagnosis and Prognosis
Accurate diagnosis and prognosis of Alzheimer's disease are crucial to
develop new therapies and reduce the associated costs. Recently, with the
advances of convolutional neural networks, methods have been proposed to
automate these two tasks using structural MRI. However, these methods often
suffer from lack of interpretability, generalization, and can be limited in
terms of performance. In this paper, we propose a novel deep framework designed
to overcome these limitations. Our framework consists of two stages. In the
first stage, we propose a deep grading model to extract meaningful features. To
enhance the robustness of these features against domain shift, we introduce an
innovative collective artificial intelligence strategy for training and
evaluating steps. In the second stage, we use a graph convolutional neural
network to better capture AD signatures. Our experiments based on 2074 subjects
show the competitive performance of our deep framework compared to
state-of-the-art methods on different datasets for both AD diagnosis and
prognosis.Comment: arXiv admin note: substantial text overlap with arXiv:2206.0324
Brain Structure Ages -- A new biomarker for multi-disease classification
Age is an important variable to describe the expected brain's anatomy status
across the normal aging trajectory. The deviation from that normative aging
trajectory may provide some insights into neurological diseases. In
neuroimaging, predicted brain age is widely used to analyze different diseases.
However, using only the brain age gap information (\ie the difference between
the chronological age and the estimated age) can be not enough informative for
disease classification problems. In this paper, we propose to extend the notion
of global brain age by estimating brain structure ages using structural
magnetic resonance imaging. To this end, an ensemble of deep learning models is
first used to estimate a 3D aging map (\ie voxel-wise age estimation). Then, a
3D segmentation mask is used to obtain the final brain structure ages. This
biomarker can be used in several situations. First, it enables to accurately
estimate the brain age for the purpose of anomaly detection at the population
level. In this situation, our approach outperforms several state-of-the-art
methods. Second, brain structure ages can be used to compute the deviation from
the normal aging process of each brain structure. This feature can be used in a
multi-disease classification task for an accurate differential diagnosis at the
subject level. Finally, the brain structure age deviations of individuals can
be visualized, providing some insights about brain abnormality and helping
clinicians in real medical contexts
Fluage et rupture dans un matériau granulaire
National audienceWe study experimentally the localization of deformation occuring at slow shear, in a 3D granular packing. We use an original method of measurement of deformation based on Diffusive Wave Spectroscopy. We evidence localized regions of strong deformations spanning a mesoscopic size of about 10 grains. We link the apparition rate of those spots to the concept of fluidity, recently used to describe the local and non-local rheology of soft glassy materials
Deep grading for MRI-based differential diagnosis of Alzheimer's disease and Frontotemporal dementia
Alzheimer's disease and Frontotemporal dementia are common forms of
neurodegenerative dementia. Behavioral alterations and cognitive impairments
are found in the clinical courses of both diseases and their differential
diagnosis is sometimes difficult for physicians. Therefore, an accurate tool
dedicated to this diagnostic challenge can be valuable in clinical practice.
However, current structural imaging methods mainly focus on the detection of
each disease but rarely on their differential diagnosis. In this paper, we
propose a deep learning based approach for both problems of disease detection
and differential diagnosis. We suggest utilizing two types of biomarkers for
this application: structure grading and structure atrophy. First, we propose to
train a large ensemble of 3D U-Nets to locally determine the anatomical
patterns of healthy people, patients with Alzheimer's disease and patients with
Frontotemporal dementia using structural MRI as input. The output of the
ensemble is a 2-channel disease's coordinate map able to be transformed into a
3D grading map which is easy to interpret for clinicians. This 2-channel map is
coupled with a multi-layer perceptron classifier for different classification
tasks. Second, we propose to combine our deep learning framework with a
traditional machine learning strategy based on volume to improve the model
discriminative capacity and robustness. After both cross-validation and
external validation, our experiments based on 3319 MRI demonstrated competitive
results of our method compared to the state-of-the-art methods for both disease
detection and differential diagnosis
Mass detection through parametric analysis and symmetry-breaking in a MEMS array
International audienceDue to their low cost, size and precision M/NEMS are efficient sensors. M/NEMS sensors are used in various domains ranging from aeronautics to medicine or telecommunication, with applications such as chemical, inertial or mass sensing. Our previous researches on mass sensing were focused on a single resonator. In this work, a symmetric array of three resonant nanobeams is analysed. The originality lies in the use of a direct parametric analysis to sense an added mass during a symmetry-breaking event
Towards quantum simulation with circular Rydberg atoms
The main objective of quantum simulation is an in-depth understanding of
many-body physics. It is important for fundamental issues (quantum phase
transitions, transport, . . . ) and for the development of innovative
materials. Analytic approaches to many-body systems are limited and the huge
size of their Hilbert space makes numerical simulations on classical computers
intractable. A quantum simulator avoids these limitations by transcribing the
system of interest into another, with the same dynamics but with interaction
parameters under control and with experimental access to all relevant
observables. Quantum simulation of spin systems is being explored with trapped
ions, neutral atoms and superconducting devices. We propose here a new paradigm
for quantum simulation of spin-1/2 arrays providing unprecedented flexibility
and allowing one to explore domains beyond the reach of other platforms. It is
based on laser-trapped circular Rydberg atoms. Their long intrinsic lifetimes
combined with the inhibition of their microwave spontaneous emission and their
low sensitivity to collisions and photoionization make trapping lifetimes in
the minute range realistic with state-of-the-art techniques. Ultra-cold
defect-free circular atom chains can be prepared by a variant of the
evaporative cooling method. This method also leads to the individual detection
of arbitrary spin observables. The proposed simulator realizes an XXZ spin-1/2
Hamiltonian with nearest-neighbor couplings ranging from a few to tens of kHz.
All the model parameters can be tuned at will, making a large range of
simulations accessible. The system evolution can be followed over times in the
range of seconds, long enough to be relevant for ground-state adiabatic
preparation and for the study of thermalization, disorder or Floquet time
crystals. This platform presents unrivaled features for quantum simulation
Interference estimated time of arrival on a 6-DOF cable-driven haptic foot platform
A Cable-Driven Locomotion Interface employs two independent cable-driven haptic foot platforms constrained in six degrees of freedom (6-DOF). Its control system and its geometry are designed for performing a wide range of trajectories that could generate cable interferences. This paper presents and analyzes computational methods for determining which cable can be released from an active actuation state while allowing control in a minimal tension state, thereby ensuring that both platforms stay in a controllable workspace. One challaging task is to develop light and fast computational algorithms for hard real time processes included in haptic display applications. Seeing that releasing a cable from an active actuation state might generate discontinuities in tension values in the other cables, this paper proposes collision prediction schemes named Interference Estimated Time of Arrival in order to reduce or completely eliminate such discontinuities
Self-Organization of Early Vocal Development in Infants and Machines: The Role of Intrinsic Motivation
International audienceWe bridge the gap between two issues in infant development: vocal development and intrinsic motivation. We propose and experimentally test the hypothesis that general mechanisms of intrinsically motivated spontaneous exploration, also called curiosity-driven learning, can self-organize developmental stages during early vocal learning. We introduce a computational model of intrinsically motivated vocal exploration, which allows the learner to autonomously structure its own vocal experiments, and thus its own learning schedule, through a drive to maximize competence progress. This model relies on a physical model of the vocal tract, the auditory system and the agent's motor control as well as vocalizations of social peers. We present computational experiments that show how such a mechanism can explain the adaptive transition from vocal self-exploration with little influence from the speech environment, to a later stage where vocal exploration becomes influenced by vocalizations of peers. Within the initial self-exploration phase, we show that a sequence of vocal production stages self-organizes, and shares properties with data from infant developmental psychology: the vocal learner first discovers how to control phonation, then focuses on vocal variations of unarticulated sounds, and finally automatically discovers and focuses on babbling with articulated proto-syllables. As the vocal learner becomes more proficient at producing complex sounds, imitating vocalizations of peers starts to provide high learning progress explaining an automatic shift from self-exploration to vocal imitation
Evaluation of automatic feature detection algorithms in EEG: application to interburst intervals
In this paper, we present a new method to compare and improve algorithms for feature detection in neonatal EEG. The method is based on the algorithmŚłs ability to compute accurate statistics to predict the results of EEG visual analysis. This method is implemented inside a Java software called EEGDiag, as part of an e-health Web portal dedicated to neonatal EEG.
EEGDiag encapsulates a component-based implementation of the detection algorithms called analyzers. Each analyzer is defined by a list of modules executed sequentially. As the libraries of modules are intended to be enriched by its users, we developed a process to evaluate the performance of new modules and analyzers using a database of expertized and categorized EEGs. The evaluation is based on the DaviesâBouldin index (DBI) which measures the quality of cluster separation, so that it will ease the building of classifiers on risk categories. For the first application we tested this method on the detection of interburst intervals (IBI) using a database of 394 EEG acquired on premature newborns. We have defined a class of IBI detectors based on a threshold of the standard deviation on contiguous short time windows, inspired by previous work. Then we determine which detector and what threshold values are the best regarding DBI, as well as the robustness of this choice. This method allows us to make counter-intuitive choices, such as removing the 50 Hz filter (power supply) to save time
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