Sleep quality worsened due to both OSA and PLMD on their own, but did not worsen further when OSA with elevated PLMI occurred, though children with both disorders had worse daytime sleepiness and restless sleep.
Children with PLMD were more likely to report prolonged sleep latency compared to OSA groups.
Children affected by both OSA and elevated periodic limb movement index were drowsier during the day and experienced more restless sleep.
There was no significant difference in total sleep time or sleep latency between the three diagnostic groups.
Children with PLMD had significantly lower REM sleep percentage compared to the other groups.
Children in the two OSA groups tended to have poorer sleep efficiency compared to the PLMD group.
The co-occurrence of OSA with elevated PLMI did not further worsen objective sleep quality beyond OSA alone.
This research suggests that two common childhood sleep disorders — periodic limb movement disorder (PLMD, where children move their legs repeatedly during sleep) and obstructive sleep apnoea (OSA, where breathing is repeatedly interrupted during sleep) — each damage sleep quality in distinct ways. Looking at 132 children who underwent overnight sleep studies, researchers found that kids with PLMD had less REM (dream) sleep, while kids with OSA tended to have lower overall sleep efficiency. Children with PLMD were also more likely to have trouble falling asleep at bedtime, as reported by parents. Interestingly, when children had both OSA and an elevated rate of limb movements during sleep, their objective sleep measurements did not get worse than having OSA alone. However, parents of these children reported more daytime sleepiness and more restless sleep than parents in the other groups. This mismatch between what the sleep study recorded and what parents observed at home highlights that standard sleep study measurements may not fully capture how a child feels or functions during the day. This research suggests that clinicians should pay attention to both conditions separately, as they affect sleep in different ways. Even when sleep studies don't show dramatic combined effects, children experiencing both disorders may still suffer meaningfully in their daily lives through increased tiredness and disrupted nighttime behavior. Comprehensive symptom reporting from parents appears to be an important complement to objective sleep testing in this population.
Dékány L, Bikov A, Benedek P. (2026). The impact of paediatric periodic limb movement disorder and obstructive sleep apnoea syndrome on sleep quality and daytime symptoms.. Sleep & breathing = Schlaf & Atmung. https://doi.org/10.1007/s11325-026-03595-1