Cerebral blood flow and cognitive function in obstructive sleep apnea syndrome

Area of Science:

• Neurology
• Sleep Medicine
• Neuroimaging

Background:

• Neuropsychological deficits are common in obstructive sleep apnea syndrome (OSAS).
• These deficits may stem from impaired cerebral blood flow (CBF).

Purpose of the Study:

• To investigate the relationship between regional CBF, cognitive function, and sleep parameters in OSAS patients.
• To assess if hypoxemia during sleep affects cerebral perfusion and cognitive performance.

Main Methods:

• Studied 20 OSAS patients (30-60 years old) using polysomnography.
• Assessed regional CBF via technetium-99m HMPAO brain perfusion scintigraphy in the morning.
• Administered cognitive function tests, focusing on verbal memory, post-polysomnography.

Main Results:

• Mean arterial oxygen saturation during sleep correlated with CBF in all brain regions.
• Verbal memory scores positively correlated with sleep duration below 90% oxygen saturation.
• CBF was significantly lower in left frontal and temporal regions compared to the right hemisphere.

Conclusions:

• OSAS is associated with reduced CBF and verbal memory deficits, linked to sleep hypoxemia.
• Decreased perfusion in left frontal and temporal lobes after apneic episodes suggests potential upper airway motor control impairment.