The Cortical Asymmetry Index for subtyping dementia patients

Category	Detail
Condition	Frontotemporal dementia (FTD) and Alzheimer's disease (AD)
Key Mechanisms	Cortical asymmetry differences measured by MRI cortical thickness using a probability distribution-based Cortical Asymmetry Index (CAI)
Target Population	Patients with FTD subtypes (bvFTD, svPPA, nfvPPA), AD patients, and healthy controls
Care Setting	Specialized cognitive disorders and dementia clinics with access to MRI and biomarker analysis

FTD patients exhibit more pronounced cortical asymmetry compared to AD, especially in the semantic variant primary progressive aphasia (svPPA).
The Cortical Asymmetry Index (CAI), derived from information theory and cortical thickness measures, can aid differential diagnosis between FTD and AD and among FTD phenotypes.
Longitudinal MRI and biomarker data support CAI's potential to track neurodegeneration progression and correlate with fluid biomarkers and cognitive measures.

Use structural MRI to assess cortical thickness asymmetry for differential diagnosis between FTD subtypes and AD.
Apply CAI based on probability distribution methods for robust cortical asymmetry measurement.
Incorporate CSF and plasma biomarkers (Aβ42, p-tau, t-tau, NfL, GFAP, UCH-L1) to support clinical diagnosis.

Monitor disease progression using longitudinal MRI scans assessing cortical asymmetry changes.
Combine clinical, cognitive, imaging, and biomarker data for comprehensive patient evaluation.

Perform follow-up MRI scans approximately every 1.5 to 2 years to evaluate cortical asymmetry progression.
Regularly assess cognitive function using tools like the Mini-Mental State Examination (MMSE).
Track fluid biomarker levels to correlate with imaging findings.

Misdiagnosis of FTD as AD due to overlapping clinical features, especially in early stages.
Interpretation challenges and computational complexity associated with probability distribution-based CAI calculation.

554 participants including 230 AD patients, 101 FTD patients (bvFTD, svPPA, nfvPPA), and 173 healthy controls

CAI and biomarker profiles can guide accurate diagnosis and monitoring but do not directly inform pharmacologic treatment decisions.

Ensure comprehensive clinical and cognitive evaluation alongside MRI and biomarker assessments.
Exclude patients with confounding neurological or psychiatric conditions (stroke, brain injury, tumor, major psychiatric disorder, alcohol abuse).
Use standardized MRI acquisition protocols and processing pipelines (e.g., FreeSurfer v6.0) for cortical thickness and asymmetry analysis.
Incorporate longitudinal follow-up to detect progression and refine diagnosis.

Clinical Scorecard: Utilizing the Cortical Asymmetry Index for Classifying Dementia Subtypes