Response to Brugniaux, Foster, and Beaudin.

What role for hypercapnia in obstructive sleep apnea?

TO THE EDITOR: The question raised by Wang et al. (5) in their recent Viewpoint is important inasmuch as apneic events in obstructive sleep apnea (OSA) are associated with both hypoxia and hypercapnia. Given the cerebrovasculature is more sensitive to hypercapnia than hypoxia (2) it is surprising, as Wang et al. (5) indicate, that the impact of OSA-related hypoxemia on neurocognitive consequenc...

Define and Conquer: How Semantics Foster Progress; A Response to Recent Commentaries

Studying cerebral hemodynamics and metabolism using simultaneous near-infrared spectroscopy and transcranial Doppler ultrasound: a hyperventilation and caffeine study

Caffeine is one of the most widely consumed psycho-stimulants in the world, yet little is known about its effects on brain oxygenation and metabolism. Using a double-blind, placebo-controlled, randomized cross-over study design, we combined transcranial Doppler ultrasound (TCD) and near-infrared spectroscopy (NIRS) to study caffeine's effect on middle cerebral artery peak blood flow velocity (V...

Effects of intermittent hypoxia on erythropoietin, soluble erythropoietin receptor and ventilation in humans.

Erythropoietin (EPO) and soluble EPO receptors (sEPOR) have been proposed to play a central role in the ventilatory acclimatisation to continuous hypoxia in mice. In this study, we demonstrated for the first time in humans (n = 9) that sEPOR is downregulated upon daytime exposure to 4 days of intermittent hypoxia (IH; 6 h·day⁻¹, cycles of 2 min of hypoxia followed by 2 min of reoxygenation; pea...

Comparing the executive function and cognitive flexibility and theory of mind in foster and non-foster children

The present study was conducted to compare executive function and cognitive flexibility and  theory of mind in foster and non-foster children. The study population included all and non-foster children in Azarshahr city in 2016. The number of participants included 42 people selected using purposeful sampling. The Tower of Hanoi test and reading mind test by eye image (RMET) were used as a measur...