Congenital Central Hypoventilation Syndrome (CCHS) patients show partial rete ntion of peripheral chemoreception despite impaired ventilatory responses to CO2 and hypoxia. The condition allows examination of central r...Congenital Central Hypoventilation Syndrome (CCHS) patients show partial rete ntion of peripheral chemoreception despite impaired ventilatory responses to CO2 and hypoxia. The condition allows examination of central responses to hyperoxia , which minimizes afferent traffic from peripheral chemoreceptors. We used functional magnetic resonance imaging to assess blood oxygen level- dependent signals over the brain during a baseline and subsequen t 2- min hyperoxia (100% O2) period in 14 CCHS and 15 control subjects. After partitioning gray matter and correcting for global effects, the images were ana lyzed using volume- of- interest time trends followed by repeated- measures A NOVA and conventional cluster analyses. Respiratory rates initially (first 20 s) fell in CCHS, but rose in control subjects; CCHS heart rate increased in the fi rst minute, and then decreased in the second minute, as in controls, but with mu ted rise and extent of decline. Multiple sites within the cerebellum, midbrain, and pons responded similarly to the challenge in both groups. Response patterns differed early in the right amygdala, paralleling initial respiratory pattern de ficits, and late in the right insula, concomitant with cardiac rate differences. Signals also differed between groups in the medial and anterior cingulate, hipp ocampus, head of caudate, and lentiform nuclei, as well as pontine and midbrain structures and regionswithin the superior temporal and inferior frontal cortical gyri. The findings emphasize that structures that can alter respiratory timing, such as the amygdala, and modulate sympathetic outflow, such as the right insul a, are deficient in CCHS. Medullary and pontine areas targeted by PHOX2B express ion are also affected.展开更多
文摘Congenital Central Hypoventilation Syndrome (CCHS) patients show partial rete ntion of peripheral chemoreception despite impaired ventilatory responses to CO2 and hypoxia. The condition allows examination of central responses to hyperoxia , which minimizes afferent traffic from peripheral chemoreceptors. We used functional magnetic resonance imaging to assess blood oxygen level- dependent signals over the brain during a baseline and subsequen t 2- min hyperoxia (100% O2) period in 14 CCHS and 15 control subjects. After partitioning gray matter and correcting for global effects, the images were ana lyzed using volume- of- interest time trends followed by repeated- measures A NOVA and conventional cluster analyses. Respiratory rates initially (first 20 s) fell in CCHS, but rose in control subjects; CCHS heart rate increased in the fi rst minute, and then decreased in the second minute, as in controls, but with mu ted rise and extent of decline. Multiple sites within the cerebellum, midbrain, and pons responded similarly to the challenge in both groups. Response patterns differed early in the right amygdala, paralleling initial respiratory pattern de ficits, and late in the right insula, concomitant with cardiac rate differences. Signals also differed between groups in the medial and anterior cingulate, hipp ocampus, head of caudate, and lentiform nuclei, as well as pontine and midbrain structures and regionswithin the superior temporal and inferior frontal cortical gyri. The findings emphasize that structures that can alter respiratory timing, such as the amygdala, and modulate sympathetic outflow, such as the right insul a, are deficient in CCHS. Medullary and pontine areas targeted by PHOX2B express ion are also affected.
