Stimulus-driven cerebrospinal fluid dynamics is impaired in glaucoma patients

Area of Science:

• Neuroscience
• Ophthalmology
• Fluid Dynamics

Background:

• Cerebrospinal fluid (CSF) dynamics are vital for brain homeostasis and waste clearance.
• The impact of age-related neurodegenerative diseases on stimulation-driven CSF flow is not well understood.

Purpose of the Study:

• To investigate alterations in CSF flow during visual stimulation in glaucoma patients compared to healthy controls.
• To explore the relationship between CSF dynamics, neuronal activity (BOLD response), and glaucoma severity.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure CSF flow and blood-oxygen-level-dependent (BOLD) response during visual stimulation.
• Mediation analysis was employed to assess the interplay between BOLD signals and CSF patterns.

Main Results:

• Glaucoma patients exhibited a decoupling of CSF inflow from visually evoked BOLD response.
• Stimulus-locked CSF patterns, including post-stimulus decreases and rebound increases, were diminished in glaucoma and correlated with disease severity.
• A flatter BOLD slope in glaucoma patients mediated the flattened CSF pattern, leading to a shallower CSF trough and reduced rebound.

Conclusions:

• Disrupted stimulation-driven CSF dynamics represent a novel pathophysiological mechanism in glaucoma.
• Altered CSF flow patterns and their relationship with BOLD response may serve as potential in vivo biomarkers for monitoring glaucoma.