Impaired glymphatic drainage underlying obstructive sleep apnea is associated with cognitive dysfunction

Area of Science:

• Neuroscience
• Radiology
• Sleep Medicine

Background:

• Obstructive sleep apnea (OSA) is common and linked to cognitive impairment.
• The exact mechanisms connecting OSA and cognitive decline are not fully understood.
• Morphological changes in perivascular spaces (PVSs) are observed in OSA patients.

Purpose of the Study:

• To investigate the relationship between OSA, PVSs, and cognitive impairment.
• To evaluate the glymphatic drainage system's fluid dynamics in OSA patients using novel DCE-MRI techniques.
• To assess the impact of CPAP treatment on glymphatic function and cognitive status in OSA.

Main Methods:

• Utilized novel dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) methods.
• Assessed fluid dynamics of the glymphatic drainage system, including inflow and outflow parameters.
• Correlated glymphatic parameters with cognitive function, hypoxia levels, and PVS morphology in OSA patients.

Main Results:

• OSA patients exhibited altered glymphatic inflow and outflow parameters, indicating impaired drainage.
• Impaired glymphatic outflow correlated with the severity of cognitive impairment and hypoxia.
• One month of CPAP treatment improved glymphatic drainage system performance in OSA patients.

Conclusions:

• OSA-induced chronic intermittent hypoxia impairs glymphatic drainage, contributing to cognitive decline.
• Ventilation improvement via CPAP may be a therapeutic strategy for OSA-related cognitive impairment.
• Morphological changes in PVSs and altered glymphatic function are key factors in OSA-associated cognitive deficits.