title: Dissonance Between Parent-Selected Bedtimes and Young Children's Circadian Physiology Influences Nighttime Settling Difficulties.
abstract: Nighttime settling difficulties (i.e., bedtime resistance, sleep-onset delay) occur in about 25% of young children and are associated with attentional, behavioral, and emotional problems. We examined whether the timing of internal (endogenous) circadian melatonin phase (i.e., dim light melatonin onset; DLMO) and its relationship with parent-selected bedtimes were related to nighttime settling behaviors. Fourteen regularly napping preschoolers (8 females; 30-36 months) participated in a 6-day protocol (parent-report of nighttime settling, actigraphic assessment of sleep onset latency, evening salivary DLMO). Average DLMO clock time was 07:40 p.m. ± 00:48 minutes, occurring 29 minutes ± 32 minutes prior to bedtime (lights-out). Children with later DLMOs had longer sleep-onset latencies (r= .62) and poorer success in falling asleep (r= -.59). Children whose bedtimes were closer to their DLMO had longer sleep-onset latencies (r= .72) and increased bedtime resistance (r= -.54). We conclude that dissonance between parent-selected bedtimes and children's circadian physiology may contribute to the development of nighttime settling difficulties in early childhood.
authors.affiliation: Department of Integrative Physiology, University of Colorado Boulder ; Department of Psychiatry and Human Behavior, The Warren Alpert Medical School of Brown University.
authors.forename: Monique K
authors.initials: MK
authors.lastname: Lebourgeois
authors.affiliation: Department of Integrative Physiology, University of Colorado Boulder.
authors.forename: Kenneth P
authors.initials: KP
authors.lastname: Wright
authors.affiliation: Department of Integrative Physiology, University of Colorado Boulder.
authors.forename: Hannah B
authors.initials: HB
authors.lastname: Lebourgeois
authors.affiliation: Child Development Center, University Children's Hospital Zurich ; Children's Research Center, University Children's Hospital Zurich.
authors.forename: Oskar G
authors.initials: OG
authors.lastname: Jenni