Figure 3.

Relative change in cerebral blood flow normalized by end-tidal carbon dioxide change in response to hypercapnia in children with obstructive sleep apnea syndrome (OSAS), snorers, and controls. Relative change in cerebral blood flow (rCBF, vertical axis), normalized by end-tidal carbon dioxide change (ΔEtCO₂, mmHg), in response to hypercapnia in children with OSAS, snorers, and controls (horizontal axis). Central line indicates median, the boxes define the area between the 25th and 75th percentiles, and the whiskers designate the most extreme points not considered outliers. rCBF/ΔEtCO₂ was significantly different between the three groups. Specifically, controls had a greater response than OSAS (P = 0.028) and snorers (P = 0.025).