Cerebral oxygenation and hemodynamics during hyperventilation and sleep in patients with Rett syndrome.

We continuously monitored changes in cerebral oxygenation and hemodynamics in the frontal lobes of six patients with Rett syndrome during the awake state, which is associated with hyperventilation (HV) and breath-holding (BH), and during sleep by near-infrared spectroscopy. We also monitored three adult volunteers during simulated episodes of HV and BH. In patients with Rett syndrome, the oxygenated hemoglobin (HbO2) and total hemoglobin (HbT) decreased significantly during HV and BH in the awake state compared with the sleep state. The HbO2 and HbT decreased gradually in adult volunteers in response to prolonged episodes of HV and BH. Further studies are required to investigate the relationship, if any, between the discovered continuous decreases in HbO2 and HbT during the awake state and the brain damage seen in patients with Rett syndrome.