Problématique : Le trouble du spectre de l’autisme (TSA) affecte plus de 1 % des enfants. Les caractéristiques communes associées au TSA sont des difficultés de communication et d’interaction sociale, ainsi qu’une rigidité ou une répétitivité dans les intérêts et comportements. Certains intérêts et comportements restreints ou répétitifs peuvent être liés à des difficultés de traitement de l’information sensorielle (TIS). De fait, entre 45 et 95 % des enfants ayant un TSA présentent des difficultés sur le plan sensoriel, affectant leur fonctionnement dans la vie quotidienne. Cependant, les données disponibles dans la littérature scientifique nous apportent peu de connaissances quant à l’évolution des habiletés sensorielles chez les enfants ayant un TSA. Objectif : L’objectif principal est de documenter l’évolution des habiletés sensorielles chez les enfants ayant un TSA entre l’âge de 3-4 ans (T1) et deux ans après (T2), au moment de l’entrée à l’école. Méthodologie : Il s’agit d’une analyse secondaire de données non traitées d’une étude prospective antérieure (de 2008 à 2010). Dans le présent projet, un devis corrélationnel rétrospectif a été utilisé pour étudier 34 enfants ayant un TSA. Les données provenant d’outils d’évaluation normalisés permettant de documenter les habiletés sensorielles des enfants dans le temps, soit le Sensory Profile (SP) et le Short Sensory Profile (SSP), ont été analysées. Résultats: Les analyses démontrent une stabilité des difficultés sensorielles chez les enfants atteints de TSA de l'âge de trois à six ans. La stabilité des scores sensoriels est indépendante de la correction par des variables contrôlées, telles que l'âge mental et la gravité du TSA. Conclusions : La persistance des difficultés sensorielles chez les enfants ayant un TSA souligne la nécessité de bien évaluer cet aspect et de le considérer lors de la planification des interventions et du suivi de ces enfants. En effet, si l’on souhaite améliorer leur fonctionnement dans la vie quotidienne et accroître leur intégration sociale, il importe de tenir compte de leurs difficultés persistantes. / Abstract : Introduction: Autism Spectrum Disorder (ASD) affects more than 1% of children. Common characteristics associated with ASD are difficulties in communication and social interaction, as well as repetitive interests and behaviors. Some restricted or repetitive interests and behaviors may be linked to difficulties in sensory processing. Indeed, between 45% and 95% of children with ASD have sensory featuresaffecting their functioning in everyday life. However, the data available in the scientific literature give us little knowledge about the evolution of sensory abilities in children with ASD. Objective:The main objective of this project was to evaluatethe evolution of sensory features in children with ASD between the age of 3-4 years (T1) and two years after (T2), when they entered school. Methods:This project is a secondary analysisof untreated data from a previous prospective study (from 2008 to 2010).In the presentproject, a retrospective correlation design was usedto study 34 children with ASD. The data from standardized assessment tools were used to evaluate children's sensory features over time, the Sensory Profile (SP) and the Short Sensory Profile (SSP), were analyzed. Results:Our analyses demonstratea stability of sensory features in children with ASD from the age of three to six years old. The stability of sensory scores is independent of correction by covariates such as mental age and autism severity. Conclusions: The persistence of sensory features in children with ASD highlights the need to adequately assess this aspect and to consider it when planning and monitoring interventions. Indeed, in order to improve their functioning in everyday life and increase their social integration, it is important to take into account their persistent sensory features.

L’objectif de cette thèse est de développer des méthodes permettant la cartographie d’un environnement tridimensionnel de grande dimension en combinant radar panoramique MMW et caméras optiques. Contrairement aux méthodes existantes de fusion de données multi-capteurs, telles que le SLAM, nous souhaitons réaliser un capteur de type RGB-D fournissant directement des mesures de profondeur enrichies par l’apparence (couleur, texture...). Après avoir modélisé géométriquement le système radar/caméra, nous proposons une méthode de calibrage originale utilisant des correspondances de points. Pour obtenir ces correspondances, des cibles permettant une mesure ponctuelle aussi bien par le radar que la caméra ont été conçues. L’approche proposée a été élaborée pour pouvoir être mise en oeuvre dans un environnement libre et par un opérateur non expert. Deuxièmement, une méthode de reconstruction de points tridimensionnels sur la base de correspondances de points radar et image a été développée. Nous montrons par une analyse théorique des incertitudes combinées des deux capteurs et par des résultats expérimentaux, que la méthode proposée est plus précise que la triangulation stéréoscopique classique pour des points éloignés comme on en trouve dans le cas de cartographie d’environnements extérieurs. Enfin, nous proposons une stratégie efficace de mise en correspondance automatique des données caméra et radar. Cette stratégie utilise deux caméras calibrées. Prenant en compte l’hétérogénéité des données radar et caméras, l’algorithme développé commence par segmenter les données radar en régions polygonales. Grâce au calibrage, l’enveloppe de chaque région est projetée dans deux images afin de définir des régions d’intérêt plus restreintes. Ces régions sont alors segmentées à leur tour en régions polygonales générant ainsi une liste restreinte d’appariement candidats. Un critère basé sur l’inter corrélation et la contrainte épipolaire est appliqué pour valider ou rejeter des paires de régions. Tant que ce critère n’est pas vérifié, les régions sont, elles même, subdivisées par segmentation. Ce processus, favorise l’appariement de régions de grande dimension en premier. L’objectif de cette approche est d’obtenir une cartographie sous forme de patchs localement denses. Les méthodes proposées, ont été testées aussi bien sur des données de synthèse que sur des données expérimentales réelles. Les résultats sont encourageants et montrent, à notre sens, la faisabilité de l’utilisation de ces deux capteurs pour la cartographie d’environnements extérieurs de grande échelle. / The main goal of this PhD work is to develop 3D mapping methods of large scale environment by combining panoramic radar and cameras. Unlike existing sensor fusion methods, such as SLAM (simultaneous localization and mapping), we want to build a RGB-D sensor which directly provides depth measurement enhanced with texture and color information. After modeling the geometry of the radar/camera system, we propose a novel calibration method using points correspondences. To obtain these points correspondences, we designed special targets allowing accurate point detection by both the radar and the camera. The proposed approach has been developed to be implemented by non-expert operators and in unconstrained environment. Secondly, a 3D reconstruction method is elaborated based on radar data and image point correspondences. A theoretical analysis is done to study the influence of the uncertainty zone of each sensor on the reconstruction method. This theoretical study, together with the experimental results, show that the proposed method outperforms the conventional stereoscopic triangulation for large scale outdoor scenes. Finally, we propose an efficient strategy for automatic data matching. This strategy uses two calibrated cameras. Taking into account the heterogeneity of cameras and radar data, the developed algorithm starts by segmenting the radar data into polygonal regions. The calibration process allows the restriction of the search by defining a region of interest in the pair of images. A similarity criterion based on both cross correlation and epipolar constraint is applied in order to validate or reject region pairs. While the similarity test is not met, the image regions are re-segmented iteratively into polygonal regions, generating thereby a shortlist of candidate matches. This process promotes the matching of large regions first which allows obtaining maps with locally dense patches. The proposed methods were tested on both synthetic and real experimental data. The results are encouraging and prove the feasibility of radar and vision sensor fusion for the 3D mapping of large scale urban environment.

Foreshadowing and flashback are two techniques that look alike because they share certain features, namely repetition and experience. These two techniques nevertheless differ in many ways and this research study thus intends differentiating between the two. Existing descriptions of the two techniques provided by critics such as Irwin and Morson do not clearly indicate the differences between them. Terminology pertaining to foreshadowing and flashback is confusingly similar. This makes the identification of these techniques in literary texts difficult, and indeed no theorist explains clearly how to go about such an identification procedure. In order to achieve the aim of this research study, the descriptive, interpretive and comparative methods are used. In addition, an adapted narratological model is employed. In this model, a text is seen as having three levels, namely content, plot and style. In the analysis of content, the topic is emphasised, while theme and atmosphere are emphasised in plot and style analysis respectively. The concept 'technique' has been explained by placing emphasis on its functions and types. With regard to types, the emphasis is on structural techniques with the focus on the second level of a text, i.e the plot, because the two techniques under study, namely foreshadowing and flashback are part of the plot. Foreshadowing is described as a technique whereby an author uses details to suggest the ultimate outcome of the plot or to meaningfully precede the appearance of other details in a literary work. The functions and types of this technique are explained. Forms of this technique include knucklebones, dreams, language, character's name, shadow, conscience, beliefs, etc. Flashback is defined as the author's interruption of the chronological sequence of events in a work of literature. The importance of this technique is also emphasised. The different types of flashback are (a) external retrospection, (b) internal retrospection, and (c) mixed retrospection. A problem with regard to the types of this technique is the fact that not all types have been identified in existing research. This study has thus added two more types of flashback, namely (a) events that have been complicated and (b) events made similar to one another. There are two ways of complicating events, namely (a) changing the chronological order of events and (b) inserting events. Differences between the above-mentioned techniques that have not received attention from theorists are identified as follows in this study: <ul> <ol>In the case of foreshadowing, an unusual event appears, while in flashback, a known event is encountered, i.e. a common, everyday event. With foreshadowing, the event itself seems to be amazing.</ol><ol> In the case of flashback, however, the event may not seem amazing in itself at first, but only causes suprise later when the reader realises that his notion of what has happened and what he thinks he has understood so far is undermined.</ol> <ol>Foreshadowing whets the reader's interest, while this does not happen in the case of flashback. Foreshadowing emphasises coming events. Flashback on the other hand reveals the origin of the problem.</ol> The application of foreshadowing has been analysed by examining its forms in various Sepedi literary works. On the other hand, the application of flashback has been analysed by investigating the use of its different types rather than its forms. In the concluding chapter, the relationship between flashback and the structure of a detective narrative has been looked into. It has been realised that there is a relation between the two concerning (a) the secret and (b) the revelation/unveiling of the secret. / Thesis (DLitt (African Languages))--University of Pretoria, 2007. / African Languages / unrestricted

La dynamique granulaire amenant à l'état critique présente un intérêt dans la compréhension de la déstabilisation menant à l'avalanche. Son étude permet d'avoir des pistes de compréhension sur des mécanismes plus complexes telles les catastrophes géophysiques (séismes, glissements de terrain, éboulements). Ainsi, lorsqu'un milieu granulaire tridimensionnel sous gravité est quasi-statiquement incliné, des précurseurs sont observés à partir d'une dizaine de degrés avant l'avalanche. Ces précurseurs correspondent à des réarrangements collectifs de grains observés à la surface qui apparaissent pseudo-périodiquement avec l'angle d'inclinaison. Cette thèse fournit une caractérisation expérimentale des précurseurs détectés à la surface par méthode optique et dans le volume par méthodes acoustiques (linéaire et non linéaire). Tout d'abord, de bonnes corrélations sont trouvées entre les réarrangements à la surface et dans le volume. Dans un second temps, l'étude est poursuivie avec une liste non exhaustive de paramètres influant sur les propriétés des précurseurs. L'état de surface des grains est crucial pour la dynamique des précurseurs. Puis, une tentative de description de la déstabilisation est réalisée avec notamment la mesure de la variation des paramètres élastiques. Les précurseurs d'avalanches correspondent à des pertes successives de rigidité du système, suivies du renforcement de ce dernier. / The granular dynamics leading to the avalanche is of interest in understanding the destabilization conducting to one. Its study implies a good train of throught in the understanding of more complex mechanisms such as geophysical disasters (earthquakes, landslides, rockslides). Thus, when a three-dimensional granular medium under gravity is quasi-statically tilted, precursors are observed from the tilt of ten degrees before the avalanche. These precursors correspond to collective rearrangements of grains observed on the free surface which appear pseudo-periodically with the angle of inclination. In order to understand this phenomenon, the thesis presents an experimental characterisation of the precursors detected on the surface by optical method and in the bulk by acoustic methods (linear and nonlinear). Firstly, good correlations were found between the surface and bulk rearrangements which led to extending the study with a non-exhaustive list of parameters affecting the precursors properties. The surface features of the grains have appeared to be particularly crucial in the precursors dynamics. Finally, an attempt at a description of the destabilization is approached with the measurement of the variation of the elastic parameters revealing that precursors of avalanches correspond to successive loss of rigidity of the system, followed by hardening of the latter.

This work focuses on analysing and improving feature detection and matching. After creating an initial framework of study, four main areas of work are researched. These areas make up the main chapters within this thesis and focus on using the Scale Invariant Feature Transform (SIFT).The preliminary analysis of the SIFT investigates how this algorithm functions. Included is an analysis of the SIFT feature descriptor space and an investigation into the noise properties of the SIFT. It introduces a novel use of the a contrario methodology and shows the success of this method as a way of discriminating between images which are likely to contain corresponding regions from images which do not. Parameter analysis of the SIFT uses both parameter sweeps and genetic algorithms as an intelligent means of setting the SIFT parameters for different image types utilising a GPGPU implementation of SIFT. The results have demonstrated which parameters are more important when optimising the algorithm and the areas within the parameter space to focus on when tuning the values. A multi-exposure, High Dynamic Range (HDR), fusion features process has been developed where the SIFT image features are matched within high contrast scenes. Bracketed exposure images are analysed and features are extracted and combined from different images to create a set of features which describe a larger dynamic range. They are shown to reduce the effects of noise and artefacts that are introduced when extracting features from HDR images directly and have a superior image matching performance. The final area is the development of a novel, 3D-based, SIFT weighting technique which utilises the 3D data from a pair of stereo images to cluster and class matched SIFT features. Weightings are applied to the matches based on the 3D properties of the features and how they cluster in order to attempt to discriminate between correct and incorrect matches using the a contrario methodology. The results show that the technique provides a method for discriminating between correct and incorrect matches and that the a contrario methodology has potential for future investigation as a method for correct feature match prediction.

This thesis focuses on the development of strategy for universal application of social networking in a school of pre-primary and primary education level and its subsequent application in a real school. It describes potential benefits of such application and discusses other ways of use of social networks in primary schools. In addition, in theoretical part it defines actors of school environment and information flows between them. Subsequently discusses about communication needs of these actors given the current communication tools and generational differences. The practical part is based on applying a specific strategy of social networks in a school in Slovakia along with the information and summarized results of this application.

Higher-level features are considered to be a potential remedy against transmission line and cross-channel degradations, currently some of the biggest problems associated with speaker verification. Phoneme durations in particular are not altered by these factors; thus a robust duration model will be a particularly useful addition to traditional cepstral based speaker verification systems. In this dissertation we investigate the feasibility of phoneme durations as a feature for speaker verification. Simple speaker specific triphone duration models are created to statistically represent the phoneme durations. Durations are obtained from an automatic hidden Markov model (HMM) based automatic speech recognition system and are modeled using single mixture Gaussian distributions. These models are applied in a speaker verification system (trained and tested on the YOHO corpus) and found to be a useful feature, even when used in isolation. When fused with acoustic features, verification performance increases significantly. A novel speech rate normalization technique is developed in order to remove some of the inherent intra-speaker variability (due to differing speech rates). Speech rate variability has a negative impact on both speaker verification and automatic speech recognition. Although the duration modelling seems to benefit only slightly from this procedure, the fused system performance improvement is substantial. Other factors known to influence the duration of phonemes are incorporated into the duration model. Utterance final lengthening is known be a consistent effect and thus “position in sentence” is modeled. “Position in word” is also modeled since triphones do not provide enough contextual information. This is found to improve performance since some vowels’ duration are particularly sensitive to its position in the word. Data scarcity becomes a problem when building speaker specific duration models. By using information from available data, unknown durations can be predicted in an attempt to overcome the data scarcity problem. To this end we develop a novel approach to predict unknown phoneme durations from the values of known phoneme durations for a particular speaker, based on the maximum likelihood criterion. This model is based on the observation that phonemes from the same broad phonetic class tend to co-vary strongly, but that there is also significant cross-class correlations. This approach is tested on the TIMIT corpus and found to be more accurate than using back-off techniques. / Dissertation (MEng)--University of Pretoria, 2009. / Electrical, Electronic and Computer Engineering / unrestricted

The primary goal of this dissertation is to develop point-based rigid and non-rigid image registration methods that have better accuracy than existing methods. We first present point-based PoIRe, which provides the framework for point-based global rigid registrations. It allows a choice of different search strategies including (a) branch-and-bound, (b) probabilistic hill-climbing, and (c) a novel hybrid method that takes advantage of the best characteristics of the other two methods. We use a robust similarity measure that is insensitive to noise, which is often introduced during feature extraction. We show the robustness of PoIRe using it to register images obtained with an electronic portal imaging device (EPID), which have large amounts of scatter and low contrast. To evaluate PoIRe we used (a) simulated images and (b) images with fiducial markers; PoIRe was extensively tested with 2D EPID images and images generated by 3D Computer Tomography (CT) and Magnetic Resonance (MR) images. PoIRe was also evaluated using benchmark data sets from the blind retrospective evaluation project (RIRE). We show that PoIRe is better than existing methods such as Iterative Closest Point (ICP) and methods based on mutual information. We also present a novel point-based local non-rigid shape registration algorithm. We extend the robust similarity measure used in PoIRe to non-rigid registrations adapting it to a free form deformation (FFD) model and making it robust to local minima, which is a drawback common to existing non-rigid point-based methods. For non-rigid registrations we show that it performs better than existing methods and that is less sensitive to starting conditions. We test our non-rigid registration method using available benchmark data sets for shape registration. Finally, we also explore the extraction of features invariant to changes in perspective and illumination, and explore how they can help improve the accuracy of multi-modal registration. For multimodal registration of EPID-DRR images we present a method based on a local descriptor defined by a vector of complex responses to a circular Gabor filter.

Escherichia coli produtoras de toxina de Shiga (STEC) são consideradas importantes patógenos de origem alimentar que apresentam o trato intestinal de ruminantes domésticos, principalmente bovinos, seu reservatório natural. Esses microrganismos estão associados a doenças severas em humanos, tais como colíte hemorrágica (CH) e síndrome urêmica hemolítica (SHU). Este trabalho teve como objetivos avaliar a ocorrência de STEC em diferentes fontes, ambientais ou não, da criação e abate de bovinos confinados. Além disso, detectar a presença dos genes stx1, stx2, ehxA e eaeA; identificar cepas O157:H7 através da pesquisa do gene uidA; evidenciar a capacidade de produção de Stx e de Eh; identificar variantes de stx e de eaeA; e determinar os sorotipos e a diversidade genética das cepas de STEC. A avaliação da presença dos genes (stx1, stx2, ehxA, eaeA e uidA) e da produção de Eh foi utilizada como triagem para a seleção de cepas possivelmente patogênicas, sendo que do total de 628 isolados avaliados, foram selecionadas 50 cepas STEC e 12 consideradas como EPEC atípicas. Das STEC, 76% foram isolados provenientes de amostras de fezes, enquanto 18% foram de amostras de carcaças e 6% de amostras de água da baia. Seis cepas isoladas de fezes e 1 de carcaça foram sorotipificadas como O157:H7, todas positivas para a presença do gene uidA. Além do sorogrupo O157, nenhum outro, dentre os principais causadores de surtos e casos esporádicos de CH e SHU, foi detectado. Das 30 cepas que apresentaram resultado positivo no ensaio de citotoxicidade em células Vero, 96,7% apresentaram gene para a produção de Stx. Em 17 das STEC foi possível identificar o tipo de Stx produzida, através de ensaio imunocromatográfico, sendo que todas apresentaram os genes correspondentes à toxina identificada, com exceção de uma cepa de carcaça que foi positiva para a produção de ambas as toxinas, mas apresentando apenas o gene stx2. Através da análise por PFGE, observou-se a disseminação e permanência de cepas STEC entre os animais. Dentre as 50 cepas STEC, 28% foram positivas para a variante Stx2d ativável e das 21 cepas eaeApositivas apenas em 8 foram detectadas variantes desse gene, sendo 7 positivas para eae-&#947; e a outra cepa positiva para eae-&#946;). Através dos resultados obtidos, podemos dizer que a pesquisa do gene uidA pode ser considerada uma ótima ferramenta na triagem de isolados do sorotipo O157:H7. Por outro lado, o gene ehxA e a produção de Eh não se mostraram como bons marcadores para pesquisa de cepas Stx positivas. Houve uma ampla diversidade de sqrotipos/sorogrupos entre as cepas STEC típicas. É importante salientar que, neste estudo, STEC O157:H7 foi detectada pela primeira vez no Brasil em amostra de carcaça de bovino criado em confinamento. A detecção de cepas STEC em amostras de fezes e principalmente em amostras de carcaças de bovinos demonstra um potencial risco à saúde pública, uma vez que tais cepas podem contaminar e chegar viáveis ao produto final. / Shiga toxin (Stx)-producing Escherichia coli (STEC) are considered important foodborne pathogens that have the intestinal tract of ruminants, in particular cattle, as reservoir. These microorganisms are associated with severe human diseases as hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS). The aims of this research were to evaluate the occurrence of STEC from different sources during the feedlot cattle breeding and slaughtering; detecting the presence of stx1, stx2, ehxA and eaeA genes; identifying O157:H7 strains through uidA; evidencing Stx and Eh production capacity; identifying stx and eaeA variants and determining STEC strains serotypes and genetic diversity. The potentially pathogenic strains were screened by detection of stx1, stx2, ehxA, eaeA and uidA, and Eh production, amongst 628 isolates studied. Fifty isolates were identified as STEC and 12 others as atypical EPEC. Among the STEC isolates, 76% were from feces, 18% from carcasses and 6% from water samples. Six strains isolated from feces and one from carcass were serotyped as O157:H7, ali being positive for the uidA. No other serogroup linked to outbreaks or sporadic cases of HC and HUS were found. From the 30 strains that showed cytotoxic effect on Vero cells, the great majority (96.7%) was positive for stx. Using an immunochromatographic assay, it was possible to identify the type of Stx produced by 17 out of the 50 STEC strains. All but one of these strains harbored the gene correspondent to the identified toxin. The other strain, even though producing both toxins, presented only stx2. It was possible to determine by PFGE the dissemination and persistence of STEC strains among the animals. 14/50 (28%) STEC strains were positive for the variant Stx2d activatable. Amongst 21 eaeA-positive strains, the variants of this gene were detected only in eight, being seven positive for eae-&#947; and the other eae-&#946;. The results showed that uidA gene can be considered an excellent tool for screening O157:H7 strains. On the other hand, ehxA and Eh production, could not be considered as good markers for Stx-positive strains detection. A great diversity of serotypes/serogroups was observed among typical STEC strains. It is important to notice that this is the first report of O157:H7 strains in carcasses trom feedlot cattle in Brazil. The detection of STEC strain in fecal samples and in carcasses trom feedlot cattle evidences the potential public health risk, once these strains can contaminate the final product.

La sclérose latérale amyotrophique (SLA) est une maladie neurodégénérative fatale. De récents travaux suggèrent une variabilité en termes d'incidence, de mortalité et de caractéristiques cliniques selon les régions géographiques et les populations. Cette thèse offre une mise à jour sur l'hétérogénéité de la SLA, accompagnée de deux études épidémiologiques et cliniques originales en Afrique et en Amérique latine. La première est une étude hospitalière multicentrique dans huit pays africains qui décrit et compare les caractéristiques sociodémographiques et cliniques, les traitements, les facteurs pronostics et la durée de survie chez les patients atteints de la SLA. Certaines caractéristiques sont plus spécifiques aux cas africains par rapport aux occidentaux, telles qu’une proportion plus élevée de patients masculins, un âge de début plus jeune, une proportion plus faible de début bulbaire et une survie plus courte que prévue. Le sous-continent et le traitement par riluzole sont des facteurs indépendamment liés à la survie du patient. La seconde étude en population générale a estimé les taux de mortalité en Équateur, pays composé d’une population majoritairement métisse. Ces résultats soutiennent l’hypothèse d’une survenue plus faible de cas SLA dans les populations métisses d’Amérique latine comparée aux populations caucasiennes d'Europe et d'Amérique du Nord. Les taux de mortalité standardisés ont été comparés entre les groupes ethniques, montrant des différences significatives entre le groupe métisse et le groupe comprenant les autres ethnies (indigènes, asiatiques et arabes). Ce travail fournit des données originales et fiables pour améliorer nos connaissances sur la SLA en Afrique et en Amérique latine. Une collaboration internationale et multidisciplinaire est cruciale pour comprendre la variabilité de la SLA dans différentes populations. / Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disorder with an invariable fatal outcome. Current evidence supports ALS variability in terms of incidence, mortality and clinical features between geographic areas and populations. This dissertation offers an updated review of ALS heterogeneity along with two original epidemiological and clinical studies in Africa and Latin America. First, a multicenter hospital-based study in eight African countries that described and compared the sociodemographic characteristics, clinical features, treatments, prognoses and survival times of patients with ALS. Certain specific characteristics were different in African cases compared to Western cases like higher proportion of male patients, younger age at onset, lower proportion of bulbar onset and shorter survival than expected. Subcontinental location and riluzole treatment are independently associated with survival. Second, a population-based study estimated ALS mortality rates in Ecuador, a predominant admixed population. The findings support a lower ALS occurrence in admixed populations from Latin America compared to European and Northern American populations. Standardized mortality rates were compared among ethnic groups with significant differences between admixed and other ethnic groups (Indigenous, Asians and Arabs). This work provides original and reliable data to improve our knowledge of ALS in Africa and Latin America. An international and multidisciplinary collaboration is crucial to understand ALS variability in different populations.