Changes of cerebral tissue oxygen saturation at sleep transitions in adolescents.

In adults, cerebral oxy-([O₂Hb]) and deoxyhemoglobin concentrations ([HHb]) change characteristically at transitions of sleep stages. The aims were to assess these changes in adolescents and additionally to measure tissue oxygen saturation (StO₂) by near infrared spectroscopy (NIRS). Previously it was reported that in adults [O₂Hb] increased and [HHb] decreased at the transition from non-rapid eye movement sleep (NREMS) to REMS and wakefulness. Transitions to NREMS from REMS/wakefulness led to a decrease in [O₂Hb] and an increase in [HHb]. We measured [O₂Hb], [HHb] and tissue oxygenation (StO₂) with NIRS approximately above the left prefrontal cortex in 12 healthy adolescent males (aged 10-16 years). We found comparable signs and magnitudes of changes in [O₂Hb] and [HHb] as observed in adults. StO₂ increased at the transitions from NREMS to REMS and decreased from REMS to NREMS and at sleep onset (all p < 0.01, linear mixed effects model). Changes in oxygen metabolism during sleep transitions are similar in adolescents and adults. In addition, we show for the first time temporal changes of StO₂ at sleep transitions.