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

Abstract

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.

Keywords: Arousals; Child; Cognition; Periodic leg movements; Periodic limb movement disorder; Polysomnography; Sleep apnea, obstructive; Sleepiness.

Figure 1

The change in the NEPSY Cognitive Index (ΔCI) after adenotonsillectomy is plotted against the change in the periodic leg movement index (ΔPLMI). R² = .037, p = .030. The few outliers with more extreme changes in PLMI were likely to be influential, as a non-parametric Spearman correlation coefficient did not confirm a significant association (rho = −.11, p = .23).

Figure 2

The change in the NEPSY Cognitive Index (ΔCI) after adenotonsillectomy is plotted against the change in the periodic leg movement with arousal index (ΔPLMAI). R² = .044, p = .017. The few outliers with more extreme changes in PLMAI were likely to be influential, as a non-parametric Spearman correlation coefficient did not confirm a significant association (rho = −.14, p = .11).