Fractal dimension shows reduced cortical complexity in Dementia with Lewy Bodies

Q: What does fractal dimension represent in this study?

Fractal dimension (FD) measures cortical complexity and reflects structural alterations linked to neurodegenerative processes.

Q: How were FD values computed from MRI data?

T1-weighted MRI scans were segmented using Freesurfer 7.3.4, and FD was computed from Freesurfer outputs using the fractalbrain toolkit.

Q: What were the main findings of FD differences between groups?

In DLB, cortical gray matter FD was significantly reduced globally and in multiple lobes, and cerebral white matter FD was also lower.

Sep 30, 2026

Uploaded by Marglet

Background: Fractal dimension (FD) quantifies cortical complexity and is altered during ageing and neurodegenerative disease, making it a potential structural marker for Dementia with Lewy bodies (DLB). Objective: Compare regional and whole-brain FD indices across DLB, Alzheimer’s disease (AD), and healthy controls. Methods: T1-weighted MRI from 87 DLB, 88 AD, and 100 matched controls were processed with Freesurfer 7.3.4 and FD computed via fractalbrain; group differences used MANOVA and Kruskal-Wallis with FDR-corrected p<0.05. Results: FD decreased globally and in multiple lobes in DLB, also in white matter, and was lower in AD than DLB in selected regions. FD correlated with ACE-R cognition and cortical thickness, supporting FD’s usefulness for DLB-AD differentiation.

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Abstract

Background

Method

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DOI: 10. 1002/alz70856_105988 BIOMARKERS POSTER PRESENTATION NEUROIMAGING Fractal dimension shows reduced cortical complexity in Dementia with Lewy Bodies Kiran Aftab1 Marcella Montagnese2 Timothy Rittman2, 3, 4 1 University of Cambridge, Cambridge, Cambridgeshire, United Kingdom 2 University of Cambridge, Cambridge, United Kingdom 3 Department of Clinical Neurosciences, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom 4 Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom Correspondence Kiran Aftab, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom. Email: [ka545@cam.ac.uk](ka545@cam.ac.uk) Abstract Background: 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). Method: 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)andAMyloid 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. Result: 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. Conclusion: 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. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2025 The Alzheimer’s Association. Alzheimer’s & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer’s Association. Alzheimer’s Dement. 2025;21(Suppl. 2):e105988. [https://doi.org/10.1002/alz70856_105988](https://doi.org/10.1002/alz70856_105988) wi[leyonlinelibrary.com/journal/alz](leyonlinelibrary.com/journal/alz) 1of1

FAQs

What does fractal dimension represent in this study?

Fractal dimension (FD) measures cortical complexity and reflects structural alterations linked to neurodegenerative processes.

How were FD values computed from MRI data?

T1-weighted MRI scans were segmented using Freesurfer 7.3.4, and FD was computed from Freesurfer outputs using the fractalbrain toolkit.

What were the main findings of FD differences between groups?

In DLB, cortical gray matter FD was significantly reduced globally and in multiple lobes, and cerebral white matter FD was also lower.

Sep 30, 2026

Uploaded by Marglet