title: Sleep spindle and slow wave frequency reflect motor skill performance in primary school-age children.
abstract: OBJECTIVE
  The role of sleep in the enhancement of motor skills has been studied extensively in adults. We aimed to determine involvement of sleep and characteristics of spindles and slow waves in a motor skill in children.
  
  
  OBJECTIVE
  We hypothesized sleep-dependence of skill enhancement and an association of interindividual differences in skill and sleep characteristics.
  
  
  METHODS
  30 children (19 females, 10.7 ± 0.8 years of age; mean ± SD) performed finger sequence tapping tasks in a repeated-measures design spanning 4 days including 1 polysomnography (PSG) night. Initial and delayed performance were assessed over 12 h of wake; 12 h with sleep; and 24 h with wake and sleep. For the 12 h with sleep, children were assigned to one of three conditions: modulation of slow waves and spindles was attempted using acoustic perturbation, and compared to yoked and no-sound control conditions.
  
  
  METHODS
  Mixed effect regression models evaluated the association of sleep, its macrostructure and spindles and slow wave parameters with initial and delayed speed and accuracy.
  
  
  CONCLUSIONS
  Children enhance their accuracy only over an interval with sleep. Unlike previously reported in adults, children enhance their speed independent of sleep, a capacity that may to be lost in adulthood. Individual differences in the dominant frequency of spindles and slow waves were predictive for performance: children performed better if they had less slow spindles, more fast spindles and faster slow waves. On the other hand, overnight enhancement of accuracy was most pronounced in children with more slow spindles and slower slow waves, i.e., the ones with an initial lower performance. Associations of spindle and slow wave characteristics with initial performance may confound interpretation of their involvement in overnight enhancement. Slower frequencies of characteristic sleep events may mark slower learning and immaturity of networks involved in motor skills.
authors.affiliation: Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands ; Department of Clinical Neurophysiology, Amsterdam Sleep Centre, Slotervaartziekenhuis Amsterdam, Netherlands.
authors.forename: Rebecca G
authors.initials: RG
authors.lastname: Astill
authors.affiliation: Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands ; Department of Neurology, Massachusetts General Hospital Boston, MA, USA.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Piantoni
authors.affiliation: Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands.
authors.forename: Roy J E M
authors.initials: RJ
authors.lastname: Raymann
authors.affiliation: Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands ; Sleepvision, Berg en Dal Netherlands.
authors.forename: Jose C
authors.initials: JC
authors.lastname: Vis
authors.affiliation: Department of Technology and Software Development, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands.
authors.forename: Joris E
authors.initials: JE
authors.lastname: Coppens
authors.affiliation: Sleep and Neuroimaging Laboratory, Department of Psychology, University of California Berkeley, CA, USA.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Walker
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center and Harvard Medical School Boston, MA, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Stickgold
authors.affiliation: Department of Emotion and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands ; Department of Anatomy and Neurosciences, VU University and Medical Center Amsterdam, Netherlands.
authors.forename: Ysbrand D
authors.initials: YD
authors.lastname: Van Der Werf
authors.affiliation: Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences Amsterdam, Netherlands ; Departments of Integrative Neurophysiology and Medical Psychology, Center for Neurogenomics and Cognitive Research (CNCR), Neuroscience Campus Amsterdam, VU University and Medical Center Amsterdam, Netherlands.
authors.forename: Eus J W
authors.initials: EJ
authors.lastname: Van Someren
keywords: children; frequency; learning; memory; motor skill; sleep; slow waves; spindles