Brain network connectivity differs in early-onset neurodegenerative dementia

Area of Science:

• Neuroscience
• Neuroimaging
• Computational Psychiatry

Background:

• Early-onset Alzheimer disease (EOAD) and behavioral variant frontotemporal dementia (bvFTD) are distinct neurodegenerative conditions.
• Understanding their unique impacts on brain network architecture is crucial for diagnosis and treatment.

Purpose of the Study:

• To investigate and compare the functional brain network architecture in patients with EOAD and bvFTD.
• To identify distinct patterns of network alterations that could aid in differentiating these diseases.

Main Methods:

• Utilized resting-state functional magnetic resonance imaging (fMRI) and 3D T1-weighted imaging.
• Applied graph analysis and connectomics to assess global and local network properties, regional functional connectivity, and interhemispheric connectivity.
• Compared 38 bvFTD patients, 37 EOAD patients, and 32 healthy controls.

Main Results:

• EOAD patients exhibited severe global functional network alterations, including reduced nodal strength and efficiency.
• bvFTD patients showed relatively preserved global architecture with focal alterations in frontoinsular and temporal regions.
• Parietal lobe connectivity breakdown differentiated EOAD from bvFTD, with EOAD showing widespread correlation loss and bvFTD showing preferential intrahemispheric disruption.

Conclusions:

• Distinct patterns of functional network topology and connectivity alterations characterize EOAD and bvFTD.
• Graph analysis and connectomics show promise as tools for clinical diagnosis and understanding pathophysiological differences in neurodegenerative dementias.