Congenital central hypoventilation syndrome (CCHS) is a rare disorder of autonomic and respiratory regulation that frequently alters oxygen delivery to the brain. In CCHS, neurocognitive function has been of great concern because of the potential for repeated hypoxemia and hypercarbia in activities of daily living in addition to hypoventilation with related hypoxemia and hypercarbia during sleep. As the world's leading referral center for CCHS, the Center for Autonomic Medicine in Pediatrics (CAMP) is engaged in ongoing research to identify factors that impact neurocognitive performance in patients with CCHS in order to optimize clinical management and improve long term neurocognitive outcomes. The purpose of this IRB-approved research study is to implement the NIH Toolbox as a standard measurement of cognitive health in patients with CCHS. Further, the study aims to determine how intrinsic and extrinsic disease factors such as age at diagnosis, PHOX2B mutation type and genotype, and nature of past and present artificial respiratory intervention affect the NIH Toolbox Cognitive scores of individuals with CCHS. Eligible participants will complete a 45-minute NIH Toolbox assessment and parents (or adult participants) will complete an associated, 15-minute Research Electronic Data Capture (REDCap) questionnaire.