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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Gray matter alterations in individuals with PTSD compared to controls : A systematic review

Sandkvist Studsare, Saga, Arvidsson, Arash January 2023 (has links)
This systematic review aims to investigate the alterations in gray matter volume (GMV) observed in the brains of individuals diagnosed with post-traumatic stress disorder (PTSD) through the Clinical Administered PTSD scale (CAPS) using Voxel-Based Morphometry (VBM) as a method. PTSD is diagnosed when an individual meets all the criteria for PTSD as defined by the DSM, which includes having experienced or witnessed a traumatic event, experiencing intrusive symptoms such as flashbacks or nightmares, avoiding triggers related to the trauma, experiencing negative changes in mood and cognition, and experiencing changes in arousal and reactivity. Previous research investigating gray matter alterations in patients with PTSD has yielded heterogeneous findings. The review incorporates a comprehensive search and analysis of pertinent studies conducted between 1995 and the present. Diverse databases were scrutinized to identify articles that fulfilled the inclusion criteria. Ultimately, a total of seven articles meeting our inclusion criteria were included in this systematic review. The sample sizes ranged from 30 to 75 participants. The control groups in the chosen articles varied, some only had healthy controls (HC), while some had trauma-exposed controls (TC) or included both. The results consistently revealed a reduction in GMV predominantly in the hippocampus, with additional areas exhibiting decreased GMV such as the bilateral hypothalamus and left inferior parietal lobule, right middle temporal gyrus, right inferior temporal gyrus, and right fusiform gyrus, as well as the bilateral calcarine cortex, left dorsal anterior cingulate cortex, left anterior cingulate cortex, and bilateral insula.
272

Brain Morphometry from Neuroimaging As A Biomarker For Alzheimer’s Disease

Aniebo, Nonyelum Benedicta 01 June 2023 (has links)
No description available.
273

The Analysis of the Impact of Trisomy 21 on Brain Morphometry in Humans

Ahmad, Yaser 01 January 2019 (has links)
Trisomy 21, caused by triplication of human chromosome 21, is also known as Down syndrome (DS) and affects every 1 out of 800 births. DS causes morphometric deviations in the brain and face as well as behavioral changes, due to gene dosage imbalances. Since many DS studies focus on adults, there are very few that explore how DS influences children. This investigation helps to fill this void in the literature by seeking to understand the differences in brain morphometry in children with DS and euploid controls. To do this, we first obtained two age- and gender-matched sample groups composed of MRI images from 1) children with DS (n=31 images, 0-4 yrs.); 2) euploid children (n = 31 images, 0-4 yrs.). MRI images were provided by the Florida Hospital (now AdventHealth) and the National Institute of Health. On these MRI images, 36 anatomical landmarks were placed throughout the brain. With the 36 landmarks, Euclidean Distance Matrix Analysis was used to measure every unique linear distance between landmarks, resulting in a total of 630 linear distances. Out of 630 linear distances, 211 (33.49%) were significantly different between the two samples (p-value < 0.05), as determined by analysis of variance (ANOVA) calculations. From these 211 linear distances, 22 were extremely different between the two samples (p-value < 0.001) and were thoroughly analyzed. Based on our results, regions of the brain that were significantly different in children with DS include the following: frontal lobe, occipital lobe, ventricles, thalamus, striatum, and corpus callosum. Such morphometric changes are likely associated with behavioral changes such as social-cognitive defects and motor-related issues commonly seen in DS.
274

A Magnetic Resonance Imaging Study of the Developmental Consequences of Childhood Lead Exposure in Adulthood

Beckwith, Travis J. 11 September 2015 (has links)
No description available.
275

Assessment of Bone Geometry in Postmenopausal Women with Osteoporosis of the Spine Before and After a 6 Month Aquatic Exercise Program

Bonnyman, Alison M. 10 1900 (has links)
<p>Background: Increased physical activity has a modest effect on the spatial distribution of bone mineral. The risks and benefits of exercise for women with osteoporosis at high risk to fracture are not known. The decompression of aquatic exercise is an option to increase exercise compliance. The dual energy absorptiometry (DXA) vertebral fracture assessment (VFA) images 2D bone geometry however measurement properties have not been established for this outcome.</p> <p>Purpose: To determine relative and absolute intra-rater reliability of DXA-based vertebral height (VH) measures and to assess the feasibility of investigating bone outcomes in women with established osteoporosis before and after a 6 month aquatic exercise program.</p> <p>Methods: DXA VFA scans of 32 women over 60 years old were analyzed on 2 occasions, 4 weeks apart. Relative reliability, intraclass correlation coefficient (95% CI) and absolute reliability, standard error of measurement (95% CI) were estimated for visible anterior, middle and posterior VHs from T4 to L4. Women with osteoporosis at high risk to fracture (clinical practice guidelines used) were recruited from two osteoporosis clinics. Feasibility of recruitment, adherence to the exercise, adherence to the assessment protocols (DXA, pQCT, physical performance measures), safety and retention were assessed.</p> <p>Results: Intra-rater reliability ICC >0.87 (0.74, 0.94) and SEM <1.17 from T10 to L4. Recruitment of 9 women in 10 weeks; average adherence 68%; pQCT data loss 46%; 1 fracture after class; retention 89% at 12 months.</p> <p>Conclusion: Further study of measurement properties of VH and protocols for recruitment, data management and safety are required.</p> / Master of Science Rehabilitation Science (MSc)
276

Increasing DBM Reliability using Distribution Independent Tests and Information Fusion Techniques

Rajagopalan, Vidya 21 January 2010 (has links)
In deformation based morphometry (DBM) group-wise differences in brain structure are measured using deformable registration and some form of statistical test. However, it is known that DBM results are sensitive to both the registration method and statistical test used. Given the lack of an objective model of group variation it has been difficult to determine the extent of the influence of registration implementation or contraints on DBM analysis. In this thesis, we use registration methods with varying levels of theoretic similarity to study the influence of registration mechanics on DBM results. We show that because of the extent of the influence of registration mechanics on DBM results, analysis of changes should always be made with a thorough understanding of the registration method used. We also show that minor variations in registration methods can lead to large changes in DBM results. When using DBM, it would be imprudent to use only one registration method to draw any conclusions about the variations being studied. In order to provide a more complete representation of inter-group changes, we propose a method for combining multiple registration methods using Dempster-Shafer evidence theory to produce belief maps of categorical changes between groups. We show that the Dempster-Shafer combination produces a unique and easy to interpret belief map of regional changes between and within groups without the complications associated with hypothesis testing. Another, often confounding, element of DBM is the parametric hypothesis test used to specify voxels undergoing significant change between the two groups. The accuracy and reliability of these tests are contingent on a number of fundamental assumptions made about the distribution of the data used in the tests. Many DBM studies often overlook these assumptions and fail to verify their validity for the data being tested. This raises many doubts about the credibility of the results from such tests. In this thesis, we propose to perform statistical analysis on DBM data using nonparametric, distribution independent hypothesis tests. With no data distributional assumptions, these tests provide both increased flexibility and reliability of DBM statistical analysis. / Ph. D.
277

Hodnocení morfologie obličeje pacientů s orofaciálními rozštěpy v návaznosti na terapeutické postupy. / Assessment of facial morphology in patients with orofacial clefts in relation to surgical protocols

Moslerová, Veronika January 2018 (has links)
The presented thesis summarizes the results of research on craniofacial morphology in patients with facial cleft defects in relation to therapeutic approaches (Caganova et al., 2014; Dadáková et al., 2016; Hoffmannova et al., 2016; Hoffmannova et al., 2018; Moslerová et al., 2018). The effect of therapy in individuals with pathological growth disorders cannot be evaluated without detailed auxological studies of control subjects whose facial morphology, longitudinal changes, or manifestations of sexual dimorphism were evaluated upon similar methodology (Koudelová et al. 2015). Therefore, the thesis was conceived as a volume of six publications complemented with a general synthetic introduction into the area of study. Together, the thesis includes probands in a broad age spectrum from birth to 15 years with a total of 294 facial 3D scans, 36 tele-X-ray face images, 3D scans of 112 gypsum palate castings. The methods of geometric morphometry and multidimensional statistics prevail in the assessment. The main clinical part of the thesis deals with the influence of two types of surgery on the facial growth and development of patients with cleft palate, namely secondary spongioplasty (SS) and neonatal cheiloplasty (NCH). Neonatal cheiloplasty (NCH) is the surgery whose effects were studied from several...
278

Pelvic belt effects on pelvic morphometry, muscle activity and body balance in patients with sacroiliac joint dysfunction

Soisson, Odette, Lube, Juliane, Germano, Andresa, Hammer, Karl-Heinz, Josten, Christoph, Sichting, Freddy, Winkler, Dirk, Milani, Thomas L., Hammer, Niels 17 March 2015 (has links) (PDF)
The sacroiliac joint (SIJ) is frequently involved in low back and pelvic girdle pain. However, morphometrical and functional characteristics related to SIJ pain are poorly defined. Pelvic belts represent one treatment option, but evidence still lacks as to their pain-reducing effects and the mechanisms involved. Addressing these two issues, this case-controlled study compares morphometric, functional and clinical data in SIJ patients and healthy controls and evaluates the effects of short-term pelvic belt application.
279

Les canis pléistocènes du sud de la France : approche biosystématique, évolutive et biochronologique / Pleistocene canids from southern France : biosystematic, evolution and biochronology

Boudadi-Maligne, Myriam 06 December 2010 (has links)
L’étude des faunes du Quaternaire s’inscrit dans une dynamique de connaissance des paléoenvironnements et est de ce fait nécessaire pour mieux cerner les contraintes environnementales qui ont rythmé la dispersion des hominidés sur l’ensemble des continents. Le genre Canis, autour duquel nous avons axé ce travail de recherche, présente la particularité d’être resté constamment présent en Europe occidentale depuis son apparition, il y a plus de trois millions d’années, jusqu’à aujourd’hui. Cette constance fait de lui, malgré son caractère ubiquiste, un excellent témoin de l’évolution des paléoenvironnements.A travers l’analyse de la variabilité des populations actuelles et l’étude de dix séries fossiles du Sud de la France couvrant le Pléistocène, de nouveaux éléments de discussion sont avancés sur l’évolution des représentants du genre. Nos résultats, couplés à l’analyse critique des données bibliographiques nous ont dès lors permis de proposer une nouvelle phylogénie. Cette dernière permet non seulement de mieux cerner les phases d’apparition et de dispersion des différentes espèces du genre Canis, mais également de démontrer son potentiel biochronologique. Ainsi, trois grandes phases dans l’évolution du genre ont pu être mises en évidence. La transition de ces espèces est corrélée à de grands événements de l’histoire des faunes quaternaires (bioevent) et autorise de ce fait l’utilisation de cette phylogénie à des fins biochronologiques ainsi qu’une discussion autour des relations entre ces espèces et les paléocommunautés animales et humaines. / Quaternary mammals form an important part of the material available for researchers focusing on paleoenvironmental reconstructions. Their study is thus often used to infer the environmental constraints that set the pace of human dispersal through the world. The genus Canis, main subject of this thesis, is present in Western Europe since its origin three million years ago. This continuous presence makes it a good candidate as a paleoenvironmental proxy, even when considering its ecological plasticity.The study of ten fossil sequences from Southern France spanning the Pleistocene, coupled with the analysis of the variability of modern populations, bring new insights on the evolution of the members of this lineage. Our results, once confronted to previous studies, allowed us to propose a new phylogeny. This new framework permits a better understanding of the apparition and disappearance of the different species, but also demonstrates the biochronological potential of the Canis genus. Three major phases have been identified in its evolutionary history. The transition between the different Canids is correlated with major events in the history of quaternary mammals (bioevent). Thus, its phylogeny can be used for biochronological purposes and has to be considered in the bigger debates that focus on the interactions between animal communities and human groups.
280

The bipolar phenotype : behavioural and neurobiological characteristics

Yip, S. W. January 2012 (has links)
Background: Adolescence and young adulthood are particularly vulnerable periods for the development of mental health disorders, including bipolar disorder (BD). Mental health screening at universities could aid in the early identification of particularly at- risk individuals, with the long-term aim of providing early treatment interventions to improve clinical outcomes. However, further research into the identification of appropriate behavioral and biological markers for vulnerability to psychiatric disorders – as well as into the acceptability and efficacy of mental health screening - is warranted. Methods: Young adults were recruited via an already existing Internet-based mental health screening survey of undergraduate students at the University of Oxford. In Study 1, qualitative interviews of young adults with and without previous mental health problems were conducted to assess the acceptability and efficacy of mental health screening within a university setting. In Studies 2-5 we explored the hypotheses of altered emotional decision-making, reward processing and neurostructural integrity as behavioral and neurobiological markers for vulnerability to bipolar disorder via the study of young adults with a common bipolar phenotype (BPP) - some of whom meet diagnostic criteria for bipolar II or not-otherwise-specified disorder (BD II/NOS). To that end, we employed a diverse range of methodologies: alcohol challenge (Study 2); neuropsychological task performance (Study 3); functional magnetic resonance imaging (fMRI; Study 4); diffusion tensor imaging (DTI) and voxel-based morphometry (VBM; Study 5). Results: Findings from Study 1 suggest that young adults are willing to participate in mental health screening within a university setting, and that such screening may be used to offer subsequent treatment interventions. Taken together, findings from Studies 2 and 4 suggest a general blunted reward response among unmedicated young adults at increased risk for BD during euthymia, and additionally suggest pathophysiological similarities between BD and alcohol use disorders (AUDs) that may provide a causal link between the elevated co-occurrence rates of the two disorders. Finally, findings from Study 5 suggest widespread white matter microstructural alterations – which are likely to be neurodevelopmental in origin – among antipsychotic- and mood-stabilizer naïve young adults with BD II/NOS. Conclusions: These data support the hypothesis of neurodevelopmental alterations identifiable prior to significant clinical impairment among young adults at increased risk of – or already meeting DSM-IV criteria for – bipolar disorder. They also suggest that young adults in higher education are willing to participate in mental health screening. Future studies should aim to identify more specific markers for individual disorders such as BD.

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