Regional cerebral blood flow alterations in obstructive sleep apnea

Abstract

Obstructive sleep apnea (OSA) is a condition characterized by upper airway muscle atonia with continued diaphragmatic efforts, resulting in repeated airway obstructions, periods of intermittent hypoxia, large thoracic pressure changes, and substantial shifts in arterial pressure with breathing cessation and resumption. The hypoxic exposure and hemodynamic changes likely induce the structural and functional deficits found in multiple brain areas, as shown by magnetic resonance imaging (MRI) procedures. Altered cerebral blood flow (CBF) may contribute to these localized deficits; thus, we examined regional CBF, using arterial spin labeling procedures, in 11 OSA (age, 49.1±12.2 years; 7 male) and 16 control subjects (42.3±10.2 years; 6 male) with a 3.0-Tesla MRI scanner. CBF maps were calculated, normalized to a common space, and regional CBF values across the brain quantified. Lowered CBF values emerged near multiple bilateral brain sites in OSA, including the corticospinal tracts, superior cerebellar peduncles, and pontocerebellar fibers. Lateralized, decreased CBF appeared near the left inferior cerebellar peduncles, left tapetum, left dorsal fornix/stria terminalis, right medial lemniscus, right red nucleus, right midbrain, and midline pons. Regional CBF values in OSA are significantly reduced in major sensory and motor fiber systems and motor regulatory sites, especially in structures mediating motor coordination; those reductions are often lateralized. The asymmetric CBF declines in motor regulatory areas may contribute to loss of coordination between upper airway and diaphragmatic musculature, and lead to further damage in the syndrome.

Sleep apnea and the subsequent risk of Parkinson’s disease: a 3-year nationwide population-based study

“…Magnetic resonance spectroscopy demonstrated that hypoxia-related metabolites and microstructural changes in the putamen are more pronounced with increasing SA severity 31. Furthermore, decreased cerebral blood flow was reported in the right red nucleus and right midbrain of patients with SA 32. These abnormal findings in the basal ganglia and midbrain of patients with SA may indicate an association between SA and the risk of PD.…”

Structural and functional neural adaptations in obstructive sleep apnea: An activation likelihood estimation meta-analysis

“…In patients with OSA, this leads to nocturnal apneas and hypopneas, intermittent hypoxia, reoxygenation and hyper-/hypocapnia events, along with sleep fragmentation, and changes in cerebral blood flow (Baril et al, 2015, Shiota et al, 2014, Yadav et al, 2013). The prevalence of OSA is noticeable in general population and around 50% in patients with cardiovascular or metabolic disorders (Khazaie et al, 2013, Khazaie et al, 2011, Lévy et al, 2015, Lurie, 2011).…”

Obstructive sleep apnea is associated with altered midbrain chemical concentrations

“…Elevated muscle sympathetic nerve activity (MSNA) correlates with altered Blood Oxygen-Level-Dependent (BOLD) signals in the midbrain in OSA, suggesting a midbrain role in eliciting the high sympathetic tone in the sleep disorder (Fatouleh et al, 2014; Lundblad et al, 2014). CBF is decreased in the right midbrain of OSA subjects (Yadav et al, 2013), which may reflect lower perfusion demand, perhaps from an altered functional state (for example, lower tonic activity), or impaired cerebral perfusion. Structural changes consistent with inflammatory or glial changes, namely diffusion decreases and volume increases, appear in the hypothalamus in OSA (Lundblad et al, 2014; Tummala et al, 2016), which projects heavily to the midbrain (Sakuma and Tada, 1984; Thompson and Swanson, 1998).…”