Periodic limb movements in sleep and attention deficit hyperactivity disorder: Are they related?
BACKGROUND
Periodic limb movements in sleep (PLMS) is an uncommon sleep disorder in the paediatric population. Recently, an association between PLMS and attention deficit hyperactivity disorder (ADHD) in children was identified.


OBJECTIVE
To review the current literature and describe the common clinical presentations and pathophysiology related to both ADHD and PLMS.


METHODS
A comprehensive, electronic medical literature review was performed using search terms related to both PLMS and ADHD, with age limits applied to select for the paediatric population. A manual review of these articles was performed to identify other key reports relating to the topic.


RESULTS
The symptoms of PLMS in children are very similar to those of ADHD. Both disorders are related to dopamine production and metabolism, and both respond to dopaminergic therapy. The coexistence of ADHD and PLMS is reported to occur with some frequency. The potential for misdiagnosis of ADHD in a child with PLMS exists, given the similar clinical presentations. Recommendations regarding the identification of children undergoing evaluation for possible ADHD who may benefit from polysomnography are suggested.


CONCLUSIONS
Both ADHD and PLMS may present with daytime symptoms of hyperactivity, impulsivity, inattentiveness and decreased school performance. Physicians should consider PLMS in the differential diagnosis of a child with ADHD symptoms.
Pockett
Charissa
C
Department of Paediatrics, Faculty of Medicine, University of Calgary, Calgary, Alberta.
Kirk
Valerie
V