title: Periodic limb movements during sleep in children with narcolepsy.
abstract: OBJECTIVE
  In adults with narcolepsy, periodic limb movements of sleep (PLMS) occur more frequently than in control population, and presence of increased PLMS is associated with greater sleep disruption and shorter mean sleep latency. This study was performed to determine whether PLMS are common in children with narcolepsy, and whether the presence of PLMS is associated with greater sleep disruption.
  
  
  METHODS
  Demographic and polysomnographic information were collected from consecutive patients diagnosed with narcolepsy identified retrospectively by diagnosis-based search. Descriptive data were compiled, and sleep characteristics of children with and without PLMS were compared.
  
  
  METHODS
  Sleep disorders center in a children's hospital.
  
  
  METHODS
  44 patients, 6-19 years old (mean 13 years, SD 3.57), were identified. Twenty-eight were African American.
  
  
  METHODS
  None.
  
  
  RESULTS
  Four patients had a PLMS index (PLMI) ≥ 5/h (considered abnormal in literature). Sixteen (36%) had "any PLMS" (PLMI > 0/h). The mean PLMI was 1.3/h (SD 2.5). Sleep was significantly more disrupted, and the mean sleep latency was shorter in patients with "any PLMS" as compared to those with no PLMS. There was no correlation between the PLMI and other diagnostic criteria for narcolepsy. "Any PLMS" were present equally in children of African American and Caucasian heritage, 35.7% vs. 37.5%.
  
  
  CONCLUSIONS
  As in adults, children with PLMS and narcolepsy have more sleep disruption and shorter mean sleep latencies than those with narcolepsy but without PLMS. Our findings also suggest that the use of adult criteria for diagnosis of "significant" PLMS in children may not be sufficiently sensitive.
authors.affiliation: University of Arkansas for Medical Sciences and Arkansas Children’s Hospital Little Rock, AR 72202, USA. jambhekarsupriya@uams.edu
authors.forename: Supriya K
authors.initials: SK
authors.lastname: Jambhekar
authors.forename: Gulnur
authors.initials: G
authors.lastname: Com
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Jones
authors.forename: Rithea
authors.initials: R
authors.lastname: Jackson
authors.forename: Maria Melguizo
authors.initials: MM
authors.lastname: Castro
authors.forename: Frances
authors.initials: F
authors.lastname: Knight
authors.forename: John L
authors.initials: JL
authors.lastname: Carroll
authors.forename: May L
authors.initials: ML
authors.lastname: Griebel
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D016022:Case-Control Studies; D002648:Child; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006776:Hospitals, Pediatric; D006801:Humans; D015994:Incidence; D008297:Male; D009290:Narcolepsy / Q000175:diagnosis* / Q000453:epidemiology*; D020189:Nocturnal Myoclonus Syndrome / Q000175:diagnosis* / Q000453:epidemiology*; D017286:Polysomnography / Q000379:methods; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D012894:Sleep Stages; D012895:Sleep, REM; D018709:Statistics, Nonparametric; D055815:Young Adult