Basal Forebrain Volume Predicts Disease Conversion in Prodromal Synucleinopathy.

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Isolated rapid eye movement sleep behavior disorder (iRBD) is a prodromal stage for Parkinson's disease (PD) and dementia with Lewy bodies (DLB).
• The basal forebrain (BF) is implicated in Lewy body disorders, but its role in early iRBD phenoconversion is unclear.
• Previous studies linked bilateral BF atrophy to cognitive decline in iRBD.

Purpose of the Study:

• To investigate basal forebrain (BF) gray matter volume differences in iRBD patients versus controls.
• To assess the predictive utility of BF volume for phenoconversion to PD or DLB.
• To explore lateralized BF atrophy effects on disease conversion.

Main Methods:

• 41 iRBD patients and 38 controls underwent MRI and longitudinal clinical assessment.
• Baseline T1-weighted MRI was used to measure left and right BF gray matter volumes.
• Cox proportional hazards models analyzed BF volumes as predictors of phenoconversion risk.

Main Results:

• No significant group differences in BF volume were observed.
• Lower BF volume correlated with poorer global cognition in iRBD.
• Bilateral BF atrophy predicted increased risk of conversion to PD or DLB.
• Left BF atrophy specifically predicted conversion to DLB.

Conclusions:

• Bilateral basal forebrain (BF) atrophy may serve as an early biomarker for phenoconversion in iRBD.
• Left-sided BF atrophy may indicate a heightened risk for developing dementia with Lewy bodies (DLB).
• BF degeneration holds prognostic value in prodromal synucleinopathies.