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Periodic limb movement disorder of sleep in children
Valerie McLaughlin Crabtree1, Anna Ivanenko, Louise Margaret O'Brien
1Kosair Children's Hospital Research Institute, Division of Pediatric Sleep Medicine, Department of Pediatrics, University of Louisville School of Medicine, 571 S. Preston Street, Louisville, KY 40202, USA.
Insights
Periodic Limb Movement Disorder (PLMD) in children is linked to Attention-Deficit/Hyperactivity Disorder (ADHD), but this connection may be due to reduced REM sleep and sleep fragmentation from PLM-induced arousals.
Area of Science:
- Pediatric Sleep Medicine
- Neurodevelopmental Disorders
Background:
- Periodic Limb Movement Disorder (PLMD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are common in children.
- The relationship between PLMD and ADHD requires further characterization in pediatric populations.
Purpose of the Study:
- To investigate sleep differences in prepubertal children with PLMD, ADHD, or both.
- To compare children with PLMD and ADHD to those with PLMD alone and healthy controls.
Main Methods:
- Retrospective chart review and community survey of children aged 5-7 years.
- Polysomnography (PSG) and parental reports were used to identify children with a Periodic Limb Movement Index (PLMI) >5.
- Comparison of sleep parameters, including REM sleep and arousals, between groups.
Main Results:
- 8.4%-11.9% of children had PLMI >5; 44.4% of these also had ADHD.
- Children with PLMD showed significantly lower REM sleep percentage compared to controls.
- Children with both PLMD and ADHD had more arousals associated with PLM (PLMa) than those with PLMD alone.
Conclusions:
- The observed link between ADHD and PLMD in children may be indirect.
- Reduced REM sleep and sleep fragmentation from PLM-induced arousals might mediate the relationship between PLMD and ADHD.
Abstract:
To characterize periodic limb movement disorder (PLMD) in a cohort of prepubertal children we examined sleep-related identifiable differences between children with PLMD and attention-deficit/hyperactivity disorder (ADHD), PLMD alone, and age-matched controls. Children were selected from a chart review of all children referred to a pediatric sleep medicine center and from a community survey of 5-7-year-old-children. Polysomnography (PSG) and parental report data from all children identified as having periodic limb movement index (PLMI) >5 were reviewed and compared with a cohort of age-matched controls. A total of 8.4% of children in the clinic-referred sample, and 11.9% of the children recruited from the community had PLMI >5. Of those, 44.4% were identified as having ADHD. Children with PLMD had significantly lower percentage of rapid eye movement (REM) than control children (P < 0.001). Children in the PLMD/ADHD group had a significantly greater number of arousals associated with PLM (PLMa) than children with PLMD only (P < 0.05). While a relationship between ADHD and PLMD was observed, it was weaker than previous reports (Chervin, R. D. et al. Sleep, 2002; 25: 213; Chervin, R. D. and Archbold, K. H. Sleep, 2001; 24: 313; Picchietti et al. J. Child Neurol., 1999; 13: 588; Picchietti et al. Mov. Disord., 1999; 14: 1000; Picchietti and Walters Sleep, 1999; 22: 297). Children in the PLMD/ADHD group were more likely to have PLMas than were children with PLMD only. We postulate that rather than a direct relationship between ADHD and PLMD, this link may be mediated by the presence of reduced REM sleep and more importantly by the sleep fragmentation associated with PLM-induced arousals.