DETERMINING SELECTIVE VOLUNTARY MOTOR CONTROL OF THE LOWER EXTREMITY IN CHILDREN WITH CEREBRAL PALSY

For physiotherapists working in neuro-paediatric gait-rehabilitation, improving motor control of the lower extremity is a major focus. Nevertheless, our understanding of selective voluntary motor control (SVMC) is in its infancy. This PhD project aimed to contribute to close this gap by investigating the nature of SVMC of the lower extremity in children with cerebral palsy (CP) and providing a psychometric robust yet sensitive measurement instrument for quantifying SVMC. The first study investigated the influence of SVMC and other lower extremity and trunk motor impairments on gait capacity using multiple regression-analyses. Although SVMC was not kept within the final model, these study results revealed the importance of SVMC in relation to muscle strength, trunk control and gait capacity. The aim of the second study was to establish validity and reliability of the German version of the ‘Selective Control Assessment of the Lower Extremity’ (SCALE). Although the psychometric properties of the German SCALE were good, information about its responsiveness is lacking. Accordingly, a systematic review was carried out to identify a SVMC measurement instrument with the highest level of evidence for its psychometric properties and best clinical utility. As the findings showed the absence of appropriate, responsive SVMC measures, the aim of the last study was to modify the existing SCALE to make it more sensitive. Due to the positive findings in relation to the psychometric properties of the SCALE, its procedure was combined with a surface electromyography Similarity Index (SI). The first validity and reliability results of the SCALE-SI are promising and serve as benchmarks when applying the SCALE-SI in future clinical and scientific practice. However, to use the SCALE-SI as an outcome measure for detecting therapy-induced changes of SVMC in children with CP, its responsiveness needs to be evaluated in future studies. Key Words: cerebral palsy, selective voluntary motor control, psychometric properties, lower extremity, gait rehabilitatio

DETERMINING SELECTIVE VOLUNTARY MOTOR CONTROL OF THE LOWER EXTREMITY IN CHILDREN WITH CEREBRAL PALSY

For physiotherapists working in neuro-paediatric gait-rehabilitation, improving motor control of the lower extremity is a major focus. Nevertheless, our understanding of selective voluntary motor control (SVMC) is in its infancy. This PhD project aimed to contribute to close this gap by investigating the nature of SVMC of the lower extremity in children with cerebral palsy (CP) and providing a psychometric robust yet sensitive measurement instrument for quantifying SVMC. The first study investigated the influence of SVMC and other lower extremity and trunk motor impairments on gait capacity using multiple regression-analyses. Although SVMC was not kept within the final model, these study results revealed the importance of SVMC in relation to muscle strength, trunk control and gait capacity. The aim of the second study was to establish validity and reliability of the German version of the ‘Selective Control Assessment of the Lower Extremity’ (SCALE). Although the psychometric properties of the German SCALE were good, information about its responsiveness is lacking. Accordingly, a systematic review was carried out to identify a SVMC measurement instrument with the highest level of evidence for its psychometric properties and best clinical utility. As the findings showed the absence of appropriate, responsive SVMC measures, the aim of the last study was to modify the existing SCALE to make it more sensitive. Due to the positive findings in relation to the psychometric properties of the SCALE, its procedure was combined with a surface electromyography Similarity Index (SI). The first validity and reliability results of the SCALE-SI are promising and serve as benchmarks when applying the SCALE-SI in future clinical and scientific practice. However, to use the SCALE-SI as an outcome measure for detecting therapy-induced changes of SVMC in children with CP, its responsiveness needs to be evaluated in future studies. Key Words: cerebral palsy, selective voluntary motor control, psychometric properties, lower extremity, gait rehabilitatio

The relationship of multimodal executive function measurement and associated neuroanatomical factors in preschoolers born very low birth weight and full term

Objective: The current study investigated executive function (EF) in preschoolers born very low birth weight (VLBW) and full term by examining the dimensionality of EF and the relationship between multimodal measures of EF. Additionally, we investigated the neuroanatomical factors that may relate to EF in this population. Participants and methods: The sample included 101 preschoolers: 61 VLBW and 40 full term (mean=45.98 months (SD=5.05). EF measures included: Bear Dragon, Gift Touch, Gift Peek, Progressive Executive Categorization Battery, parent rated EF (BRIEF-P), and Child Compliance observational coding. Magnetic resonance imaging (MRI) data were analyzed through voxel-based morphometry (VBM) for a subset of preschoolers. Results: As expected, full term preschoolers were found to have higher EF scores than VLBW preschoolers on all EF measures. When principal component analysis (PCA) was used for the combined group to assess the dimensionality of EF, only one factor emerged that included all four EF performance measures and excluded BRIEF-P scores and Compliance scores. In neuroanatomical analyses, preschoolers born full term had larger gray matter volumes in bilateral temporal, frontal paracentral, putamen, right inferior parietal, and right cerebellum anterior lobe. Preschoolers born VLBW had greater volumes for bilateral frontal, occipital, right cerebellum, right occipital, left frontal, left anterior cingulate, and left parahippocampal regions. In the combined sample, increased gray matter in the right occipital area was related to poorer EF. Additionally, increases in gray matter in the bilateral temporal, right temporal, right insula and right putamen were related to greater EF performance. Conclusion: In this sample, EF performance measures loaded together onto a one-dimensional construct. EF and structural differences were found between VLBW and full term groups: EF was poorer, and structural volumes in the temporal and parietal areas were decreased and volumes in the frontal and occipital areas were increased in the VLBW group relative to the full term group. When examining the relationship between EF and structural volumes in the combined group, stronger EF performance was correlated with increased volume in temporal and deep gray matter as well as decreases in right occipital volume. The limitations in placing these results into the current literature are discussed

Multivariate Analysis of MR Images in Temporal Lobe Epilepsy

Epilepsy stands aside from other neurological diseases because clinical patterns of progression are unknown: The etiology of each epilepsy case is unique and so it is the individual prognosis. Temporal lobe epilepsy (TLE) is the most frequent type of focal epilepsy and the surgical excision of the hippocampus and the surrounding tissue is an accepted treatment in refractory cases, specially when seizures become frequent increasingly affecting the performance of daily tasks and significantly decreasing the quality of life of the patient. The sensitivity of clinical imaging is poor for patients with no hippocampal involvement and invasive procedures such as the Wada test and intracranial EEG are required to detect and lateralize epileptogenic tissue. This thesis develops imaging processing techniques using quantitative relaxometry and diffusion tensor imaging with the aiming to provide a less invasive alternative when detectability is low. Chapter 2 develops the concept of individual feature maps on regions of interest. A laterality score on these maps correctly distinguished left TLE from right TLE in 12 out of 15 patients. Chapter 3 explores machine learning models to detect TLE, obtaining perfect classification for left patients, and 88.9% accuracy for right TLE patients. Chapter 4 focuses on temporal lobe asymmetry developing a voxel-based method for assessing asymmetry and verifying its applicability to individual predictions (92% accuracy) and group-wise statistical analyses. Informative ROI and voxel-based informative features are described for each experiment, demonstrating the relative importance of mean diffusivity over other MR imaging alternatives in identification and lateralization of TLE patients. Finally, the conclusion chapter discuss contributions, main limitations and outlining options for future research

2006 Eighteenth Annual IMSA Presentation Day

We believe that our goal of creating decidedly-different learners is already being met and will make a profound impact on the future of humanity.https://digitalcommons.imsa.edu/archives_sir/1020/thumbnail.jp

Epilepsy

Epilepsy is the most common neurological disorder globally, affecting approximately 50 million people of all ages. It is one of the oldest diseases described in literature from remote ancient civilizations 2000-3000 years ago. Despite its long history and wide spread, epilepsy is still surrounded by myth and prejudice, which can only be overcome with great difficulty. The term epilepsy is derived from the Greek verb epilambanein, which by itself means to be seized and to be overwhelmed by surprise or attack. Therefore, epilepsy is a condition of getting over, seized, or attacked. The twelve very interesting chapters of this book cover various aspects of epileptology from the history and milestones of epilepsy as a disease entity, to the most recent advances in understanding and diagnosing epilepsy

Using compartment models of diffusion MRI to investigate the preterm brain

Preterm birth is the leading cause of neonatal mortality, with survivors experiencing motor, cognitive and other deficits at increased rates. In preterm infancy, the developing brain undergoes folding, myelination, and rapid cellular growth. Diffusion-Weighted Magnetic Resonance Imaging (DW MRI) is an imaging modality that allows noninvasive inference of cellular microstructure in living tissue, and its parameters reflect changes in brain tissue composition. In this thesis, we employ compartment models of DW MRI to investigate the microstructure in preterm-born subjects at different ages. Within infants, we have used the NODDI model to investigate longitudinal changes in neurite density and orientation dispersion within the white matter, cerebral cortex and thalamus, explaining known trends in diffusion tensor parameters with greater specificity. We then used a quantitative T2 sequence to develop and investigate a novel, multi-modal parameter known as the ‘g-ratio’. We have also investigated changing microstructural geometry within the cortex. Immediately after preterm birth, the highly-ordered underlying cellular structure makes diffusion in the cortex almost entirely radial. This undergoes a transition to a disordered and isotropic state over the first weeks of life, which we have used the DIAMOND model to quantify. This radiality decreases at a rate that depends on the cortical lobe. In a cohort of young adults born extremely preterm, we have quantified differences in brain microstructure compared to term-born controls. In preterm subjects, the brain structures are smaller than for controls, leading to increased partial volume in some regions of interest. We introduce a method to infer diffusion parameters in partial volume, even for regions which are smaller than the diffusion resolution. Overall, this thesis utilises and evaluates a variety of compartment models of DW MRI. By developing and applying principled and robust methodology, we present new insights into microstructure within the preterm-born brain