Tracking glymphatic dysfunction in isolated rapid eye movement sleep behavior disorder: a longitudinal neuroimaging...

Area of Science:

• Neuroimaging
• Neurology
• Biomarkers

Background:

• Isolated REM sleep behavior disorder (iRBD) is a prodromal stage for alpha-synucleinopathies.
• Identifying biomarkers to predict conversion is crucial for early intervention.

Purpose of the Study:

• To investigate baseline diffusion tensor imaging along the perivascular space (DTI-ALPS) index differences in iRBD patients who progress to neurodegenerative disease (iRBD-C) versus those who do not (iRBD-NC).
• To assess longitudinal changes in the DTI-ALPS index in iRBD patients.

Main Methods:

• Prospective study of 48 iRBD patients and 20 healthy controls with a minimum three-year follow-up.
• Magnetic resonance imaging (MRI) was used to calculate the DTI-ALPS index.
• Comparison of DTI-ALPS indices among iRBD-C, iRBD-NC, and control groups, with a subset undergoing rescans.

Main Results:

• iRBD-C patients had significantly lower baseline DTI-ALPS indices compared to controls.
• No significant difference in baseline DTI-ALPS was found between iRBD-NC and controls.
• Longitudinal analysis revealed a bilateral reduction in the ALPS index in iRBD patients, associated with cognitive changes.

Conclusions:

• The baseline DTI-ALPS index shows promise as a predictive biomarker for iRBD conversion to alpha-synucleinopathy.
• The observed decrease in the ALPS index over time suggests ongoing neurodegenerative processes.