2026 American Academy of Neurology Abstract Website

Objective:

This study aimed to investigate the impact of untreated OSA on cerebrovascular reactivity and compliance, and how these alterations may increase stroke risk.

Background:

Obstructive sleep apnea (OSA) is defined as episodic nocturnal hypoxia that causes sympathetic activation and systemic inflammation, which may compromise cerebrovascular integrity. OSA is a prevalent and treatable sleep disorder that is recognized as a modifiable risk factor for cerebrovascular accidents (CVAs).

Design/Methods:

We conducted a review and analysis of the literature surrounding the relationship between OSA and stroke. By assessing studies that used transcranial doppler ultrasonography (TCD) to assess cerebral vasoreactivity and vascular compliance. Parameters in these studies included the breath-holding index (BHI), the visual evoked flow velocity response (VEFVR), and the middle cerebral artery pulsatility and resistance indices. Risk stratification tools such as STOP-BANG and polysomnographic metrics (AHI, RDI, ODI) were evaluated in relation to these cerebrovascular markers.

Results:

Across multiple studies, a higher risk or severity of OSA was significantly associated with impaired cerebral vasoreactivity and reduced vascular compliance. This was most notable in the anterior circulation. BHI values <0.69 and VEFVR ≤14% were common among patients at moderate to high risk for OSA. Additionally, repeated episodes of overnight oxygen desaturation correlated with markers of cerebral small-vessel disease. This includes increased white matter hyperintensities and reduced vessel compliance.

Conclusions:

OSA is often dismissed but is a significant contributor to cerebrovascular changes and stroke. These findings stress the importance of routine OSA screening in stroke patients. Additionally, these suggest that early interventions, such as overnight CPAP, may preserve cerebral hemodynamics and reduce CVA incidence.