Dopaminergic damage pattern predicts phenoconversion time in isolated rapid eye movement sleep behavior disorder.

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) is a prodromal stage for synucleinopathies.
• The phenoconversion time from iRBD to synucleinopathies is currently unpredictable.
• Early identification of patients at high risk for phenoconversion is crucial for timely intervention.

Purpose of the Study:

• To investigate the whole-brain dopaminergic damage pattern (DDP) in iRBD patients.
• To analyze the progression of dopaminergic damage with disease advancement.
• To predict the phenoconversion time to synucleinopathies in individual iRBD patients.

Main Methods:

• 33 iRBD patients and 20 healthy controls underwent 11C-CFT-PET scans.
• Patients were followed for 2-10 years, with phenoconversion year defined as the base year.
• A support vector machine model with leave-one-out cross-validation was employed for prediction.

Main Results:

• Dopaminergic degeneration in iRBD commenced approximately 6 years before clinical conversion.
• The dopaminergic damage pattern demonstrated high accuracy in predicting phenoconversion at various time points (AUC 0.807-0.940).
• Predicted phenoconversion stages strongly correlated with whole-brain dopaminergic levels (r = -0.740, p < 0.001).

Conclusions:

• Whole-brain dopaminergic damage patterns can accurately predict phenoconversion time in individual iRBD patients.
• This predictive capability may facilitate the early screening of patients for synucleinopathy development.
• Early identification and intervention can potentially alter disease trajectory.