Periodic leg movements during sleep in children scheduled for adenotonsillectomy: frequency, persistence, and impact

OBJECTIVE

The aim of this study was to assess the frequency and potential clinical impact of periodic leg movements during sleep (PLMS), with or without arousals, as recorded incidentally from children before and after adenotonsillectomy (AT).

METHODS

Children scheduled for AT for any clinical indications who participated in the Washtenaw County Adenotonsillectomy Cohort II were studied at enrollment and again 6 months thereafter. Assessments included laboratory-based polysomnography, a Multiple Sleep Latency Test (MSLT), parent-completed behavioral rating scales, neuropsychological testing, and psychiatric evaluation.

RESULTS

Participants included 144 children (81 boys) aged 3-12 years. Children generally showed mild to moderate obstructive sleep apnea (median respiratory disturbance index 4.5 (Q1 = 2.0, Q3 = 9.5)) at baseline, and 15 subjects (10%) had at least five periodic leg movements per hour of sleep (PLMI ≥ 5). After surgery, 21 (15%) of n = 137 subjects who had follow-up studies showed PLMI ≥ 5 (p = 0.0067). Improvements were noted after surgery in the respiratory disturbance index; insomnia symptoms; sleepiness symptoms; mean sleep latencies; hyperactive behavior; memory, learning, attention, and executive functioning on NEPSY assessments; and frequency of attention-deficit/hyperactivity disorder (DSM-IV criteria). However, PLMI ≥ 5 failed to show associations with worse morbidity in these domains at baseline or follow-up. New appearance of PLMI ≥ 5 after surgery failed to predict worsening of these morbidities (all p > 0.05), with only one exception (NEPSY) where the magnitude of association was nonetheless negligible. Similar findings emerged for periodic leg movements with arousals (PLMAI ≥ 1).

CONCLUSION

PLMS, with and without arousals, become more common after AT in children. However, results in this setting did not suggest substantial clinical impact.

Normative values of polysomnographic parameters in childhood and adolescence: arousal events

OBJECTIVE

This study focused on differences in arousals during sleep, using the arousal rules of the American Academy of Sleep Medicine, by gender, age, and maturity in healthy children.

METHODS

One-night polysomnography was performed on 209 healthy German children (age 1-18 years) at their habitual bedtimes in 16 laboratories. Subjects were grouped by gender (112 females, 97 males), age, and Tanner stage.

RESULTS

Normative values of arousal events in sleep are presented, including indexes of spontaneous and respiratory arousals, total electroencephalogram (EEG) arousals, phasic increase in submental electromyogram (EMG) in stage R, and leg movements. With increasing age, a decrease was seen in: EEG arousal index ≥1-2.9 s, EEG arousal index ≥3 s, index of total EEG arousals, index of respiratory arousals, chin EMG enhancement in stage R ≥1-2.9 and ≥3 s, index of total leg movements, and leg movements with EEG arousals (p<0.05). Only spontaneous arousals showed no association with age. There was a significant negative correlation between Tanner stage and arousals ≥1-2.9 s, respiratory arousals, leg movements, and leg movements with arousals (p<0.05). Only arousals ≥3 s and total leg movements showed gender differences (p<0.05).

CONCLUSIONS

For the diagnosis of pediatric sleep disturbances, the given arousal data enable estimation of the degree of deviation from normal findings for age and maturity. There is need for further research on, and further discussion of, the arousal rules of the American Academy of Sleep Medicine.

Normative values of polysomnographic parameters in childhood and adolescence: quantitative sleep parameters

OBJECTIVE

To provide normative values for sleep macroarchitecture of healthy children aged 1-18 years using the AASM sleep scoring criteria, assessing the effects of gender, age, and Tanner pubertal stage.

METHODS

One-night polysomnography was performed at subjects' habitual bedtimes in 16 laboratories on 209 healthy German children.

RESULTS

Normal values of sleep macrostructure show significant age dependencies (p<0.05). Increasing with age: awakening index, R latency (RL), sleep efficiency (SE) (total sleep time (TST)/sleep period time (SPT)) and SE (TST/time in bed), stage N2, mean sleep cycle duration, number of stage shifts. Decreasing with age: TST, SPT, wake after sleep onset, stage N3, stage R, movement time (MT), number of sleep cycles. The following sleep parameters show a dependency on Tanner stages as well as corresponding age (p<0.05):TST, SPT, awakening index, R latency, stage N2, stage N3, MT, number of sleep cycles, mean sleep cycle duration. No gender dependencies were found.

CONCLUSION

The given study, considering AASM rules, shows the development of sleep in normal children ages 1-18. Subject selection criteria and other factors influencing sleep as well AASM guideline modifications including scoring arousals in N2 and scoring MT as a measure of sleep fragmentation are discussed.

Sleep spindle evolution from infancy to adolescence

OBJECTIVE

To investigate the development of frontally recorded sleep spindles from infancy to adolescence to provide normative data for pediatric sleep medicine.

METHODS

Sleep spindle activity was investigated in 120 healthy subjects aged 3 months to 16 years in 12 age groups. At 2 a.m. (min 1:17 a.m., max 3:18 a.m.) 10 min of NREM 2 was checked. Spindles were visually scored in the electroencephalogram from F4/A1.

RESULTS

The age dependency of interspindle interval, length of spindle, and spindle density, was statistically significant (Kruskal-Wallis p<0.0001). There were U-shaped curves for spindle length, spindle density, and an inverted U-shaped curve for the interspindle interval. Results of the post hoc U-test p<0.05 (Bonferroni corrected, m=66): Spindle length was minimal at 1.7 up to 3.0 years. Spindle density (number of spindles) was minimal between the ages of 1.7 and 2.3 years, thereafter there was a high increase that reached a plateau at age 5 years and remained up to 16 years. Interspindle interval was maximal at 1.7 and 2.3 years.

CONCLUSIONS

Sleep spindle activity changes with maturation in terms of length and density.

SIGNIFICANCE

The establishment of age-related normative data of sleep spindle activity can improve identification of NREM 2 in infancy, childhood, and adolescence, and enable detection of delayed neural maturation and/or sleep instability.

Schlafverhalten bei Kindern mit Tic-Störungen - eine polysomnographische Studie

Zusammenfassung: Fragestellung: Charakterisierung des Schlafmusters einer größeren Gruppe Kinder mit Tic-Störung sowie Untersuchung ob und wie Veränderungen des Schlafs mit der Schwere der Tic-Störung assoziiert sind. Methodik: Das Schlafverhalten von 25, zum Untersuchungszeitpunkt unmedizierten Kinder mit chronischer Tic-Störung wurde polysomnographisch untersucht und mit den Befunden von 22 gesunden Kontrollen verglichen. Zwischen beiden Gruppen bestanden keine Unterschiede hinsichtlich Alter, Geschlechtsverhältnis und Intelligenz. Ergebnisse: Kinder mit einer Tic-Störung zeigten eine reduzierte Schlafqualität sowie vermehrtes, bewegungsbezogenes Arousal im Vergleich zu gesunden Kontrollen. Hinsichtlich des Schlafs ging bei Kindern mit Tic-Störung eine schwerere Ausprägung der Tics mit häufigeren bewegungsbezogenen Arousals einher. Die Anzahl der kurzen, mit motorischen Phänomenen assoziierten Arousals korrelierte mit geringerer Schlafeffizienz, verzögertem Schlafbeginn und verlängerter Tiefschlaflatenz. Des weiteren bestimmten geringere Schlafeffizienz und verlängerte Tiefschlaflatenz bei Kindern mit Tic-Störung die Schwere der Tics am Tag. Schlussfolgerungen: Bei Kindern mit Tic-Störung scheint ein Zusammenhang zwischen den bewegungsbezogenen Arousals im Schlaf und der Ausprägung der Tics am Tag zu bestehen. Beeinträchtigungen des Schlafs bei Tic-Störungen könnten die Tic-Symptomatik am Tag verschlechtern.

Periodic leg movements in sleep and periodic limb movement disorder: prevalence, clinical significance and treatment

Periodic leg movements in sleep (PLMS) are a frequent finding in polysomnography. The prevalence of PLMS is estimated to be 4-11% in adults. In childhood, PLMS rarely occur although medical conditions like sleep apnea syndrome or neuropsychiatric disorders can lead to high rates of PLMS. In the elderly, PLMS are also common in subjects without sleep disturbances. In sleep studies, PLMS are found most frequently in restless legs syndrome (RLS) and often occur in narcolepsy, sleep apnea syndrome and REM sleep behavior disorder. Some patients with otherwise unexplained insomnia or hypersomnia reveal an elevated number of PLMS, a condition defined as periodic limb movement disorder (PLMD). PLMS were found also in various medical and neurological disorders that do not primarily affect sleep. A summary of these is presented. In sleep disorders related to dopaminergic dysfunction such as RLS, PLMS are considered to be a symptom of the disease. In other disorders like primary insomnia, the clinical relevance of PLMS is still being controversially discussed. Studies with findings both pro and contra are referred. To date, only a few studies have evaluated the efficacy of therapeutic substances in reducing PLMS in PLMD patients. Their results need to be confirmed in controlled randomized trials.

EFNS guidelines on management of restless legs syndrome and periodic limb movement disorder in sleep

In 2003, the EFNS Task Force was set up for putting forth guidelines for the management of the Restless Legs Syndrome (RLS) and the Periodic Limb Movement Disorder (PLMD). After determining the objectives for management and the search strategy for primary and secondary RLS and for PLMD, a review of the scientific literature up to 2004 was performed for the drug classes and interventions employed in treatment (drugs acting on the adrenoreceptor, antiepileptic drugs, benzodiazepines/hypnotics, dopaminergic agents, opioids, other treatments). Previous guidelines were consulted. All trials were analysed according to class of evidence, and recommendations formed according to the 2004 EFNS criteria for rating. Dopaminergic agents came out as having the best evidence for efficacy in primary RLS. Reported adverse events were usually mild and reversible; augmentation was a feature with dopaminergic agents. No controlled trials were available for RLS in children and for RLS during pregnancy. The following level A recommendations can be offered: for primary RLS, cabergoline, gabapentin, pergolide, ropinirole, levodopa and rotigotine by transdermal delivery (the latter two for short-term use) are effective in relieving the symptoms. Transdermal oestradiol is ineffective for PLMD.

Multidimensional scaling of pediatric sleep breathing problems and bio-behavioral correlates

STUDY OBJECTIVES

Complex relationships exist between pediatric sleep disorders and daytime behavior. Using a multidimensional scaling model, we investigated these relationships in 126 children with sleep breathing disorders (SBD).

METHOD

Validated questionnaires on nighttime behavior, daytime behavior, and respiratory health were administered to a large number of school children in Belgium. Children who met the criterion of having at least one sleep-related breathing problem (three or more times per week during the past six months) were selected for further analyses. A total of 26 indicators were defined and modeled, including sleep problems, sleep efficiency, sleep environment, sleep enuresis, internalised and externalised behavioral problems, respiratory health of the child and relatives, smoking exposure, and caffeine consumption.

RESULTS

From 3,045 questionnaire responses 4.1% of the children were reported to have a SBD symptom. SBD children differed on sleep and health domains from non-SBD children. Furthermore, through scaling of the (dis)similarities among the 26 indicators the SBD child was able to be modeled. By way of an internal analysis of the data-matrix the following indicators were eliminated: sleep correlates, health of the family, and behavior rated by teachers, followed by caffeine intake, drugs, and behavior rated by the parents. This revealed a two-dimensional model, consisting of primary SBD and secondary SBD.

CONCLUSION

Children with SBD differ on many domains from children without such disorders and an underlying two-fold SBD concept was found. Firstly, the SBD-indicator positioned in between investigated correlates with disorders of initiating and maintaining sleep and sleep hyperhydrosis on one hand and with respiratory-related illnesses on the other; this was labeled primary SBD. Secondly, the SDB-indicator not closely associated with any of the investigated correlates can be interpreted as secondary SBD.