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Fractal dimension shows reduced cortical complexity in Dementia with Lewy Bodies

Poster No:

162

Submission Type:

Abstract Submission

Authors:

Kiran Aftab¹, Marcella Montagnese¹, Timothy Rittman¹

Institutions:

¹University of Cambridge, Cambridge, United Kingdom

First Author:

Kiran Aftab
University of Cambridge
Cambridge, United Kingdom

Co-Author(s):

Marcella Montagnese
University of Cambridge
Cambridge, United Kingdom

Timothy Rittman
University of Cambridge
Cambridge, United Kingdom

Introduction:

Fractal dimension (FD) is a measure of cortical complexity which is altered in ageing and other neurodegenerative disorders. It can serve as a useful structural marker to detect neurodegenerative changes in Dementia with Lewy bodies (DLB). We assessed the regional and whole brain fractal dimension indices in DLB in comparison to healthy controls and Alzheimer's disease (AD).

Methods:

We included T1 weighted MRI scans of 87 DLB, 88 AD and 100 age- and gender-matched healthy controls from the National Alzheimer's Coordinating Center (NACC), Neuroimaging of Inflammation in Memory and Related Other Disorders (NIMROD), Multimodal Imaging in Lewy Body Disorders (MILOS) and AMyloid imaging for Phenotyping LEwy body dementia (AMPLE) datasets. We segmented the cortical gray matter and white matter using Freesurfer version 7.3.4 and computed FD from the freesurfer outputs using the fractalbrain toolkit. Statistical analysis was performed using the R statistical package to explore group-wise differences using MANOVA and Kruskal‐Wallis tests. The significance level was set at false-discovery rate (FDR) corrected p < 0.05.

Results:

Cortical gray matter FD was significantly reduced globally as well as in bilateral frontal, temporal, parietal and occipital lobes in DLB compared to healthy controls. Moreover, FD was significantly lower in the cerebral white matter. Cortical gray matter FD was also reduced in AD compared to DLB globally and in bilateral parietal and left temporal lobes regionally. Cortical gray matter FD correlated with Addenbrooke's Cognitive Examination – Revised (ACE-R) total scores and mean cortical thickness.

Supporting Image: Screenshot2024-12-17201809.png

·Correlation between Cerebral gray matter FD and ACE-R total scores

Conclusions:

Cortical complexity is reduced in the gray and white matter in DLB and can also be used to differentiate DLB from AD patients. Correlation with cognition and other structural markers may help in understanding disease-specific structural changes.

Disorders of the Nervous System:

Neurodegenerative/ Late Life (eg. Parkinson’s, Alzheimer’s) ¹

Modeling and Analysis Methods:

Other Methods ²

Neuroanatomy, Physiology, Metabolism and Neurotransmission:

Neuroanatomy Other

Keywords:

Degenerative Disease

STRUCTURAL MRI

Other - Cortical complexity

^1|2Indicates the priority used for review

Abstract Information

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Please indicate below if your study was a "resting state" or "task-activation” study.

Other

Healthy subjects only or patients (note that patient studies may also involve healthy subjects):

Patients

Was this research conducted in the United States?

Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.

Yes

Were any animal research approved by the relevant IACUC or other animal research panel? NOTE: Any animal studies without IACUC approval will be automatically rejected.

Not applicable

Please indicate which methods were used in your research:

Structural MRI

For human MRI, what field strength scanner do you use?

3.0T

Which processing packages did you use for your study?

Free Surfer

Provide references using APA citation style.

Marzi, C. (2020). Toward a more reliable characterization of fractal properties of the cerebral cortex of healthy subjects during the lifespan. Scientific reports, 10(1), 16957.

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