Electroencephalographic sleep profiles and hypothalamic-pituitary-adrenocortical (HPA)-activity in kindergarten children: early indication of poor sleep quality associated with increased cortisol secretion

J Psychiatr Res. 2008 Jun;42(7):532-43. doi: 10.1016/j.jpsychires.2007.05.010. Epub 2007 Jul 23.


Objectives: In children, objective data carried out from sleep EEG monitoring are scarce. Furthermore, results associating the hypothalamic-pituitary-adrenocortical (HPA)-activity with sleep EEG measurements in children are missing. Therefore, our study aimed to investigate in preschool-children the association between sleep patterns and endocrine activity. Furthermore, children's behavioral/emotional difficulties and competences were assessed in order to correlate psychological strain with sleep measures.

Participants and methods: Sixty-seven kindergarten children (35 boys and 32 girls) aged 5.34 underwent EEG-monitoring for one night. For baseline HPA-activity assessment, saliva samples were collected immediately after awakening, whereas saliva samples before, while and after a psychological challenge were used to assess the HPA-activity under stress conditions.

Results: Compared to girls, boys showed significantly more REM sleep time. After cluster analysis, children labeled as 'poor' sleepers (n=27; 40,30%) showed significantly increased morning cortisol values, as compared to 'good' sleepers (n=22; 32,83%). Furthermore, increased cortisol AUC values under stress conditions were significantly associated with an elevated number of awakenings after sleep onset, and more sleep time in stages 1 and 2. In addition, an increased sleep efficiency was significantly correlated with self-reported emotional/behavioral difficulties, i.e. with low degrees of impulsivity (r=-.31; p<.05) and lower degrees of social inhibition and peer victimiziation (r=-.26, p<.05).

Conclusions: Our results underlined that already in preschool years, associations between objectively examined unfavorable sleep patterns, increased HPA-system activity and more difficult behavioral and psychosocial dimensions may be observed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child Behavior Disorders / diagnosis
  • Child Behavior Disorders / epidemiology
  • Child Day Care Centers / statistics & numerical data*
  • Child, Preschool
  • Electroencephalography*
  • Female
  • Humans
  • Hydrocortisone / analysis
  • Hydrocortisone / metabolism*
  • Hypothalamo-Hypophyseal System / metabolism*
  • Male
  • Pituitary-Adrenal System / metabolism*
  • Polysomnography
  • Psychology
  • Saliva / chemistry
  • Severity of Illness Index
  • Sleep Deprivation / diagnosis
  • Sleep Deprivation / epidemiology*
  • Sleep Deprivation / metabolism*
  • Sleep Stages / physiology
  • Wakefulness


  • Hydrocortisone