A quarterly publication of the Autism Research Institute

The Autism Research Review International is quarterly publication of the Autism Research Institute

Fall, 2020 | Number 4, Volume 34

Restless legs syndrome may often underlie insomnia in ASD

A new study suggests that sleep problems in children with autism spectrum disorders (ASD) may frequently stem from a condition known as restless leg syndrome (RLS). 

Restless leg syndrome causes unpleasant sensations in the legs that lead to an overwhelming urge to move them. The symptoms are strongest in late afternoon and at night, and are most severe when people are resting. 

RLS affects 7% to 10% of the general population and is considered to be a neurological sensory disorder. The syndrome appears to be related to dysfunction of dopamine pathways in the basal ganglia. While the cause is unknown in most cases, the condition is genetically influenced and one known risk factor is iron deficiency. 

In the new study, Michelle Kanney and colleagues conducted a chart review of 103 children diagnosed with ASD and chronic insomnia and seen at their sleep center. Patients underwent clinical assessment as well as an overnight sleep study and measurement of their iron levels. 

The researchers say that 41 of the children were diagnosed with RLS, and diagnosis of RLS was associated with significantly lower serum ferritin (iron) levels. They add, “The presence of leg kicking, body rocking, or any symptoms involving the legs highly correlated with the diagnosis of RLS.” 

The researchers add that nearly all of the children responded positively to treatment. Interventions included iron supplementation (given to 25 children, with 23 improving), the anticonvulsant gabapentin (given to 12 children, all of whom improved), or combination therapy (given to 3 children, all of whom improved). They conclude, “Initial assessment [of sleep problems in individuals with ASD] should include a thorough query of behaviors related to nocturnal motor complaints, because RLS may be a treatable cause of sleep disruption.”

Kanney and colleagues say that of the children diagnosed with insomnia due to restless legs syndrome, nearly all improved with treatment.

Citations

“Rethinking bedtime resistance in children with autism: is restless legs syndrome to blame?”, Michelle L. Kanney, Jeffrey S. Durmer, Lynn Marie Trotti, and Roberta Leu, Journal of Clinical Sleep Medicine, August 17, 2020 (online). Address: Michelle Kanney, Emory University School of Medicine and Children’s Healthcare of AtlantaEgleston Campus, Atlanta, Georgia 30322.