The purpose of this study was to compare the academic achievement of students through the use of standardized testing to examine the relationship of participation in a computer-based phonics instructional system called Fast ForWord®. The sample included students enrolled in the fifth and sixth grades at four elementary schools in the Grainger County, Tennessee, school system. The comparison group consisted of same-grade peers at the four elementary schools in Grainger County who were not enrolled in the Fast ForWord® program. Students' scores were compared using the 2003 Terra Nova standardized assessment test and using their 2001 and 2002 test scores as a control. Comparisons were made using the reading, language, math, science, and social studies subsections of the Terra Nova. Differences between students who received Fast ForWord® and students who did not receive Fast ForWord® were analyzed. The study examined the variables of gender, school enrollment, socioeconomic status, time of intervention, and ability grouping. These variables were examined with analysis of covariance to determine differences. When differences did exist between groups, posthoc tests were used to determine specific differences between groups. The findings indicated that there were measurable differences in the performance of students who received Fast ForWord® compared to students who did not receive Fast ForWord®. Significant differences were found in reading and language subsections of the Terra Nova test for students who had participated in the Fast ForWord® reading program. The findings from the examination of other variables indicated that gender as well as gender x the intervention (Fast ForWord®) interaction were the same for females and males in their performance on the Terra Nova. The findings from the variable socioeconomic status were determined using system data for free/reduced or paid meals. The study determined that socioeconomic status did not significantly affect scores of students including the socioeconomic status x the intervention interaction. The study did determine differences in students' performance among schools attended. The study found some differences for intervention administration times and among ability groups. Posthoc tests were performed to determine which groups were different.

On estime que plus de la moitié de population mondiale sait parler au moins deux langues et que 40% de cette population bilingue utilise les deux langues au quotidien. Les psycholinguistes et les neuropsycholinguistes se sont rapidement intéressés au fonctionnement du cerveau bilingue et à la façon dont deux langues pouvaient partager un seul cerveau. Ainsi, de nombreuses recherches ont porté sur la représentation de plusieurs langues dans le cerveau ainsi que sur les mécanismes permettant de passer d’une langue à l’autre, mais aussi sur la période développementale sensible à l’apprentissage des langues.Dans ce travail, nous nous sommes intéressés au rôle de l’âge d’acquisition et du niveau de compétence des deux langues sur a) la représentation des substrats cérébraux, b) la plasticité cérébrale et c) la capacité d’alterner entre les deux langues. Pour cela nous comparons des locuteurs bilingues précoces -qui ont appris les deux langues avant 3 ans- et des locuteurs bilingues tardifs -qui ont appris la deuxième langue après 10 ans- tous ayant atteint un très bon niveau de compétence dans les deux langues. Le niveau langagier et le fonctionnement exécutif des participants ont été mesurés à l’aide de plusieurs tâches linguistiques et non linguistiques. Grâce à la technique d’imagerie par résonances magnétiques fonctionnelles (IRMf), nous avons pu identifier les substrats neuronaux des deux langues pour chacun des groupes, les aires impliquées dans le contrôle des langues ainsi que les changements cérébraux dus à l’apprentissage précoce de deux langues. De manière générale, les résultats montrent que la compétence langagière, plutôt que l’âge d’acquisition, aurait un rôle essentiel sur la représentation des langues. En revanche, l’âge d’acquisition serait déterminant en ce qui concerne la structure cérébrale des certaines aires impliquées dans les processus langagiers. / It is estimated that more than half of the world's population speaks two languages and that 40% of the population uses both languages on a daily basis. Psycholinguists and neuropsycholinguists became interested early in the way in which two languages could share a single brain. They have therefore been interested in the representation of several languages in the bilingual brain, in the sensitive period during which languages are learned and also in the mechanisms that allow bilinguals to switch from one language to another without apparent effort. In this work, we investigated the role of the age of acquisition and proficiency of languages and the influence of two languages a) on the representation of cerebral substrates of two languages, b) on the cerebral plasticity, c) and on the mechanisms of language control. For this purpose, we compare early bilingual speakers, who learned both languages before the age of 3 years, and late bilingual speakers who learned the second language after 10 years, both of whom had a very good level of proficiency in both languages. Participants were assessed in a wide range of linguistic and non-linguistic tasks to measure language level and executive functioning. Using the functional magnetic resonance imaging technique, we were able to identify the neuronal substrates of the two languages for each group and the areas involved in language control, as well as cerebral changes due to the early learning of two languages. In general, the results show that language proficiency, rather than the age of acquisition, has an essential role on the representation of languages, but that the age of acquisition is decisive in regards of cerebral structure of certain areas related to language.

<p>Neuroimaging and neurophysiology techniques were used to study some aspects of cortical sensory and motor system reorganisation in patients in the chronic phase after stroke. Using Diffusion Tensor Imaging, we found that the degree of white matter integrity of the corticofugal tracts (CFT) was positively related to grip strength. Structural changes of the CFT were also associated with functional changes in the corticospinal pathways, measured using Transcranial Magnetic Stimulation. This suggests that structural and functional integrity of the CFT is essential for upper limb function after stroke.</p><p>Using functional magnetic resonance imaging (fMRI), to measure brain activity during slow and fast passive hand movements, we found that velocity-dependent brain activity correlated positively with neural contribution to passive movement resistance in the hand in ipsilateral primary sensory (S1) and motor (M1) cortex in both patients and controls. This suggests a cortical involvement in the hyperactive reflex response of flexor muscles upon fast passive stretch.</p><p>Effects of a four week passive-active movement training programme were evaluated in chronic stroke patients. The group improved in range of motion and upper limb function after the training. The patients also reported improvements in a variety of daily tasks requiring the use of the affected upper limb. </p><p>Finally, we used fMRI to explore if brain activity during passive hand movement is related to time after stroke, and if such activity can be affected with intense training. In patients, reduced activity over time was found in supplementary motor area (SMA), contralateral M1 and prefrontal and parietal association areas along with ipsilateral cerebellum. After training, brain activity increased in SMA, ipsilateral S1 and intraparietal sulcus, and contralateral cerebellum in parallel with functional improvements of the upper limb. The findings suggest a use-dependent modification of cortical activation patterns in the affected hand after stroke. </p>

Neuroimaging and neurophysiology techniques were used to study some aspects of cortical sensory and motor system reorganisation in patients in the chronic phase after stroke. Using Diffusion Tensor Imaging, we found that the degree of white matter integrity of the corticofugal tracts (CFT) was positively related to grip strength. Structural changes of the CFT were also associated with functional changes in the corticospinal pathways, measured using Transcranial Magnetic Stimulation. This suggests that structural and functional integrity of the CFT is essential for upper limb function after stroke. Using functional magnetic resonance imaging (fMRI), to measure brain activity during slow and fast passive hand movements, we found that velocity-dependent brain activity correlated positively with neural contribution to passive movement resistance in the hand in ipsilateral primary sensory (S1) and motor (M1) cortex in both patients and controls. This suggests a cortical involvement in the hyperactive reflex response of flexor muscles upon fast passive stretch. Effects of a four week passive-active movement training programme were evaluated in chronic stroke patients. The group improved in range of motion and upper limb function after the training. The patients also reported improvements in a variety of daily tasks requiring the use of the affected upper limb. Finally, we used fMRI to explore if brain activity during passive hand movement is related to time after stroke, and if such activity can be affected with intense training. In patients, reduced activity over time was found in supplementary motor area (SMA), contralateral M1 and prefrontal and parietal association areas along with ipsilateral cerebellum. After training, brain activity increased in SMA, ipsilateral S1 and intraparietal sulcus, and contralateral cerebellum in parallel with functional improvements of the upper limb. The findings suggest a use-dependent modification of cortical activation patterns in the affected hand after stroke.

Over the years, considerable research has been done showing the advantages of early identification of hearing loss and its impact on children in developing speech and language skills. Although the universal early hearing detection and intervention (EHDI) program is fully functional in developed countries it has not been actualized in developing global regions like Asia, Africa and Latin America. The primary reason could be precise government policies and the necessary funds to support them. There is also a lack of awareness and initiative form the parent's side. The purpose of this paper is to describe and support the need for a universal early detection of hearing loss and intervention program in India. Objectives for developing a universal early identification and intervention program and the recommendations for actualizing them have been included. / text

Alzheimer’s disease (AD) is a rapidly growing public health concern causing severe challenges to the health care system. Affecting the lives of more than 5 million Americans, it is characterized by brain-related morphological changes coupled with decrements in performance on tasks involving cognitive function such as those assessing memory and problem-solving abilities. Fortunately, current scientific research provides evidence that this trend towards rapid cognitive decline in older adults is not immutable, but rather can be attenuated through a simple adjustment to regular engagement in aerobic exercise. To date, numerous studies have associated regular cardiovascular exercise to changes in brain function and structure. In particular, aerobic exercise has been shown to have a direct effect on the hippocampus (HC), one of the earliest regions of the brain to be affected in AD, which plays an important role in learning and memory. Scientific research on animal models has demonstrated increased adult hippocampal neurogenesis (AHN), or the birth of new neurons, in the dentate gyrus (DG) subregion of the hippocampus as a response to increases in aerobic exercise. Such findings have led to the hypothesis that aerobic exercise can improve cognitive performance, more specifically hippocampal-dependent learning and memory, through the formation of new hippocampal neurons. Similarly, in human studies, previous research has shown that significant improvements in cardiovascular fitness are positively correlated with increased hippocampal volume. Structural increases in hippocampal volume are thought to be mediated by increased angiogenesis, or the generation of new blood vessels, which in turn are correlated with significant improvements in spatial memory, a task determined by memory function. The benefits of aerobic exercise, nonetheless, are not limited to the hippocampus. As people age, atrophy of the brain is also inclusive of the prefrontal cortex, a region implicated in planning and decision making. Scientific literature has shown, that similar to the hippocampus, increases in aerobic exercise, directly result to increases in grey matter volume in the prefrontal lobe and increases in white matter volume in the genu of the corpus callosum. Such structural changes in the prefrontal lobe are correlated with enhanced decision making on cognitive tasks, an essential component of executive function. For the purposes of this study, an effective method of evaluating whether changes in brain structure due to higher cardiorespiratory fitness have an association with cognitive function was through the administration of the Digital Clock Drawing Test (dCDT). The dCDT is a recently developed cognitive test based on the traditional Clock Drawing Test (CDT) that uses a digital pen and allows for the measurement of several parameters such as “Ink time” and “Think time.” Recent scientific studies report that such parameters may have a potential enhanced sensitivity to detecting cognitive change as compared to the traditional CDT. Therefore, the dCDT has come forward as an advantageous approach for testing cognitive skills in aging individuals such as those assessing executive and motor function, and semantic memory, as it happens in real time. DCDT parameters such as total time to complete the clock drawing, total ink time, total think time, total ink length, and clock size have been shown to differ significantly among subjects of varying degrees of cognitive impairment such as AD, mild cognitive impairment (MCI), and healthy, non-demented controls. Patients who were clinically diagnosed as cognitively impaired spent a greater amount of time thinking and drawing on both the command and copy clocks conditions as compared to healthy, non-demented individuals. Similarly, patients affected by greater cognitive impairments, such as AD, tended to draw smaller clocks in terms of height and width of the clock face that required less total ink length to complete the clock drawing, when compared to healthy controls and MCI participants. Findings showed that AD patients appeared to be working longer (greater time of completion) though producing less output (smaller clock and shorted ink length) as compared to non-impaired individuals. Variations of graphomotor latencies in the dCDT performance, therefore, are associated with individual’s cognitive capacities. The goal of this study is to investigate the associations between cardiorespiratory fitness based on VO2 max testing and cognitive constructs such as memory, executive function, and gross motor processing speeds as measured by graphomotor latencies and drawing patterns using the dCDT in healthy, non-demented older adults. I hypothesize that greater cardiorespiratory fitness will be negatively associated with graphomotor timed latencies in various parameters of the dCDT, given that exercise has known effects on the brain regions responsible for executive function and memory. To test these hypotheses, cardiorespiratory fitness and dCDT data from 12 sedentary older adults between the ages of 55 and 85 years from a larger study in the Brain Plasticity and Neuroimaging Laboratory at Boston University were collected and analyzed. A multiple regression analysis was used to predict the dCDT measures from individual’s cardiorespiratory fitness using estimated VO2 max levels. Results showed that cardiorespiratory fitness in older adults is inversely associated with graphomotor times in both the command and copy test conditions as predicted by our hypothesis. In particular, greater cardiorespiratory fitness was associated with shorter total ink time for both clock drawing testing conditions. These results held when controlled for age, sex, and education; higher cardiorespiratory fit older adults performed better (a shorter time is needed to achieve the same outcome) on tasks requiring greater cognitive constructs such as memory, executive function, and motor processing speeds. Therefore, it can be concluded that cardiorespiratory fitness may be a neurodegenerative protector in aging adults supporting its beneficial role as a therapeutic agent for cognitive decline in older adults.

No description available.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Identifying targets in cluttered scenes is critical for our interactions in complex environments. Our visual system is challenged to both detect elusive targets that we may want to avoid or chase and discriminate between targets that are highly similar. These tasks require our visual system to become an expert at detecting distinctive features that help us differentiate between indistinguishable targets. As the human brain is trained on this type of visual tasks, we observe changes in its function that correspond to improved performance. We use functional brain imaging, to measure learning-dependent modulations of brain activation and investigate the processes that mediate functional brain plasticity. I propose that dissociable brain mechanisms are engaged when detecting targets in clutter vs. discriminating between highly similar targets: for the former, background clutter needs to be suppressed for the target to be recognised, whereas for the latter, neurons are tuned to respond to fine differences. Although GABAergic inhibition is known to suppress redundant neuronal populations and tune neuronal representations, its role in visual learning remains largely unexplored. Here, I propose that GABAergic inhibition plays an important role in visual plasticity through training on these tasks. The purpose of my PhD is to investigate the inhibitory mechanisms that mediate visual perceptual learning; in particular, learning to detect patterns in visual clutter and discriminate between highly similar patterns. I show that BOLD signals as measured by functional Magnetic Resonance Imaging (fMRI) do not differentiate between the two proposed mechanisms. In contrast, Magnetic Resonance Spectroscopy (MRS) provides strong evidence for the distinct involvement of GABAergic inhibition in visual plasticity. Further, my findings show GABA changes during the time-course of learning providing evidence for a distinct role of GABA in learning-dependent plasticity across different brain regions involved in visual learning. Finally, I test the causal link between inhibitory contributions and visual plasticity using a brain stimulation intervention that perturbs the excitation-inhibition balance in the visual cortex and facilitates learning.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal