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873 results on '"Georgiou‐Karistianis, Nellie"'

13. Large-scale comparative visualisation of sets of multidimensional data

Author

Vohl, Dany, Barnes, David G., Fluke, Christopher J., Poudel, Govinda, Georgiou-Karistianis, Nellie, Hassan, Amr H., Benovitski, Yuri, Wong, Tsz Ho, Kaluza, Owen, Nguyen, Toan D., and Bonnington, C. Paul

Subjects
Computer Science - Human-Computer Interaction, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We present encube $-$ a qualitative, quantitative and comparative visualisation and analysis system, with application to high-resolution, immersive three-dimensional environments and desktop displays. encube extends previous comparative visualisation systems by considering: 1) the integration of comparative visualisation and analysis into a unified system; 2) the documentation of the discovery process; and 3) an approach that enables scientists to continue the research process once back at their desktop. Our solution enables tablets, smartphones or laptops to be used as interaction units for manipulating, organising, and querying data. We highlight the modularity of encube, allowing additional functionalities to be included as required. Additionally, our approach supports a high level of collaboration within the physical environment. We show how our implementation of encube operates in a large-scale, hybrid visualisation and supercomputing environment using the CAVE2 at Monash University, and on a local desktop, making it a versatile solution. We discuss how our approach can help accelerate the discovery rate in a variety of research scenarios., Comment: 26 pages, 11 figures, 5 tables. Accepted for publication in PeerJ Computer Science

Published
2016
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24. Clinical Determinants of Dual Tasking in People With Premanifest Huntington Disease

Author

Reyes, Alvaro, Bartlett, Danielle M., Rankin, Timothy J., Zaenker, Pauline, Turner, Kate, Teo, Wei-Peng, Fu, Shih Ching, Domingos, Josefa, Georgiou-Karistianis, Nellie, Ziman, Mel, and Cruickshank, Travis M.

Subjects
Diagnosis, Psychological aspects, Complications and side effects, Risk factors, Health aspects, Multitasking (Human behavior) -- Health aspects, Psychomotor disorders -- Risk factors -- Diagnosis, Huntington's disease -- Psychological aspects -- Complications and side effects, Huntington's chorea -- Psychological aspects -- Complications and side effects
Abstract

Introduction Deficits in dual tasking are a disabling aspect of Huntington disease (HD) that worsens as the disease advances. (1) Studies have reported dual-tasking deficiencies on counting and postural stability, [...], Objective. Dual-tasking deficiencies are common in people with Huntington disease (HD) and contribute to reduced functional independence. To date, few studies have investigated the determinants of dual-tasking deficiencies in this population. The reliability of dual-tasking measures has also been poorly investigated in HD. The purpose of this study was to investigate the influence of clinical determinants on dual-tasking performance and to determine the association of disease burden outcomes on dual-tasking performance in individuals with premanifest HD. Methods. Thirty-six individuals with premanifest HD and 28 age- and sex-matched healthy controls were recruited for this study. Participants performed 3 single-task (2 cognitive and 1 motor) and 2 dual-task assessments, comprising motor (postural stability) and cognitive (simple or complex mental arithmetic) components. In addition, participants performed a comprehensive clinical battery comprising motor, cognitive, mood, and sleep assessments as well as lifestyle and disease burden measures. Results. Poorer sleep quality was associated with greater cognitive dual-task cost in individuals with premanifest HD. Compared with healthy controls, people with premanifest HD demonstrated an impaired capacity to dual task. Dual-task measures exhibited acceptable test-retest reliability in premanifest HD and healthy control groups. Conclusion. These results show that dual-tasking measures are sensitive and reliable in individuals with premanifest HD. Furthermore, poor sleep quality is associated with worse cognitive performance on dual tasks, which should be considered by rehabilitation specialists when examining and therapeutically managing dual-tasking problems in individuals with HD and other neurodegenerative populations in the future. Impact. This study adds important knowledge to the sparse literature on dual-tasking deficiencies in people with HD. When examining and therapeutically managing dual-tasking problems in this and other neurodegenerative populations, rehabilitation specialists should consider that people with premanifest HD may have an impaired capacity to dual task. Clinicians also should assess sleep quality, as poorer sleep quality is associated with worse cognitive performance on dual tasks in these individuals. Lay Summary. If you have premanifest HD and poor quality of sleep, you may pay more attention to maintaining postural stability rather than performing arithmetic calculations to reduce the risk of falling. Keywords: Dual Task Cost, Sleep Quality, Disease Burden

Published
2021
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25. Localized Changes in Dentate Nucleus Shape and Magnetic Susceptibility in Friedreich Ataxia.

Author

Harding, Ian H., Nur Karim, Muhammad Ikhsan, Selvadurai, Louisa P., Corben, Louise A., Delatycki, Martin B., Monti, Serena, Saccà, Francesco, Georgiou‐Karistianis, Nellie, Cocozza, Sirio, and Egan, Gary F.

Abstract

Background: The dentate nuclei of the cerebellum are key sites of neuropathology in Friedreich ataxia (FRDA). Reduced dentate nucleus volume and increased mean magnetic susceptibility, a proxy of iron concentration, have been reported by magnetic resonance imaging studies in people with FRDA. Here, we investigate whether these changes are regionally heterogeneous. Methods: Quantitative susceptibility mapping data were acquired from 49 people with FRDA and 46 healthy controls. The dentate nuclei were manually segmented and analyzed using three dimensional vertex‐based shape modeling and voxel‐based assessments to identify regional changes in morphometry and susceptibility, respectively. Results: Individuals with FRDA, relative to healthy controls, showed significant bilateral surface contraction most strongly at the rostral and caudal boundaries of the dentate nuclei. The magnitude of this surface contraction correlated with disease duration, and to a lesser extent, ataxia severity. Significantly greater susceptibility was also evident in the FRDA cohort relative to controls, but was instead localized to bilateral dorsomedial areas, and also correlated with disease duration and ataxia severity. Conclusions: Changes in the structure of the dentate nuclei in FRDA are not spatially uniform. Atrophy is greatest in areas with high gray matter density, whereas increases in susceptibility—reflecting iron concentration, demyelination, and/or gliosis—predominate in the medial white matter. These findings converge with established histological reports and indicate that regional measures of dentate nucleus substructure are more sensitive measures of disease expression than full‐structure averages. Biomarker development and therapeutic strategies that directly target the dentate nuclei, such as gene therapies, may be optimized by targeting these areas of maximal pathology. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Published
2024
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26. Gradient of microstructural damage along the dentato‐thalamo‐cortical tract in Friedreich ataxia.

Author

Cocozza, Sirio, Bosticardo, Sara, Battocchio, Matteo, Corben, Louise, Delatycki, Martin, Egan, Gary, Georgiou‐Karistianis, Nellie, Monti, Serena, Palma, Giuseppe, Pane, Chiara, Saccà, Francesco, Schiavi, Simona, Selvadurai, Louisa, Tranfa, Mario, Daducci, Alessandro, Brunetti, Arturo, and Harding, Ian H.

Subjects
EFFERENT pathways, DENTATE nucleus, ATAXIA, WHITE matter (Nerve tissue), DIFFUSION magnetic resonance imaging
Abstract

Objective: The dentato‐thalamo‐cortical tract (DTT) is the main cerebellar efferent pathway. Degeneration of the DTT is a core feature of Friedreich ataxia (FRDA). However, it remains unclear whether DTT disruption is spatially specific, with some segments being more impacted than others. This study aimed to investigate microstructural integrity along the DTT in FRDA using a profilometry diffusion MRI (dMRI) approach. Methods: MRI data from 45 individuals with FRDA (mean age: 33.2 ± 13.2, Male/Female: 26/19) and 37 healthy controls (mean age: 36.5 ± 12.7, Male/Female:18/19) were included in this cross‐sectional multicenter study. A profilometry analysis was performed on dMRI data by first using tractography to define the DTT as the white matter pathway connecting the dentate nucleus to the contralateral motor cortex. The tract was then divided into 100 segments, and dMRI metrics of microstructural integrity (fractional anisotropy, mean diffusivity and radial diffusivity) at each segment were compared between groups. The process was replicated on the arcuate fasciculus for comparison. Results: Across all diffusion metrics, the region of the DTT connecting the dentate nucleus and thalamus was more impacted in FRDA than downstream cerebral sections from the thalamus to the cortex. The arcuate fasciculus was minimally impacted. Interpretation: Our study further expands the current knowledge about brain involvement in FRDA, showing that microstructural abnormalities within the DTT are weighted to early segments of the tract (i.e., the superior cerebellar peduncle). These findings are consistent with the hypothesis of DTT undergoing anterograde degeneration arising from the dentate nuclei and progressing to the primary motor cortex. [ABSTRACT FROM AUTHOR]

Published
2024
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42. Longitudinal imaging highlights preferential basal ganglia circuit atrophy in Huntington’s disease

Author

Liu, Chin-Fu, primary, Younes, Laurent, additional, Tong, Xiao, additional, Hinkle, Jared T, additional, Wang, Maggie, additional, Phatak, Sanika, additional, Xu, Xin, additional, Bu, Xuan, additional, Looi, Vivian, additional, Bang, Jee, additional, Tabrizi, Sarah J, additional, Scahill, Rachael I, additional, Paulsen, Jane S, additional, Georgiou-Karistianis, Nellie, additional, Faria, Andreia V, additional, Miller, Michael I, additional, Ratnanather, J Tilak, additional, and Ross, Christopher A, additional

Published
2023
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