Periodic Limb Movement Disorder (PLMD) is characterized by the periodic (every 20-40 seconds) and sustained (0.5-4.0 seconds in duration) contractions of one or both front leg muscles often causing unperceived arousals or awakenings from light or deep sleep. These contractions result in repetitive jerks for about 2 seconds of the toes, feet, legs, arms, and/or thighs, which often occur in stages 1 and 2 of NREM sleep and disrupt the quality of sleep. There appears to be a strong correlation between Periodic Limb Movement Disorder and ADHD based on initial research by sleep specialists. Sleep specialists and other experts in the field have not been able to determine if the Periodic Limb Movement Disorder causes some forms of ADHD, or whether they both exist simultaneously.

Many children and adolescents with Periodic Limb Movement Disorder display considerable amounts of oppositional behaviors and a very touchy, moody temperament due to not feeling rested when they awaken in the morning. This difficult temperament is caused by their frequent periodic limb movements in the night that prevent these children from getting into their deepest levels of sleep enough hours of the night so they do not feel rested the next morning. Many of these children also resist going to sleep or have difficulty falling asleep at night.

This sleep disorder is correctable or can usually be improved significantly with medication taken before bedtime that diminishes or stops the limb movements. Some sleep specialists are prescribing Neurontin, and some Clonadine or L-Dopa before bedtime. Neurontin and L-Dopa reduce or stop the periodic limb movements so that the student gets a restful night's sleep. The Clonadine helps the student fall asleep quicker so that s/he gets a longer night's sleep, although Clonadine does not stop the leg movements during sleep. Both Neurotin and Clonadine have been used successfully with children for several years, whereas L-Dopa use with children is newer with little known about long-term effects on children.

Many sleep specialists have reported that Neurotin appears to be the safest medication with children, although it has been known to cause some moodiness, crying, and depressive tendencies in a few children. These side effects subside with discontinuation of the Neurotin.

A brand new and more benign form of treatment may be a 12 week iron supplement therapy in cases where the child may have a Serum Ferritin deficiency causing the Periodic Limb Movement Disorder. A pediatrician can order a simple blood sample taken to check the child/adolescent’s serum ferritin level and determine if a deficiency exists. This would be the simplest and quickest form of treatment if this is the cause of the child’s nighttime restlessness and periodic limb movements. Based on new research in the field of sleep medicine, iron supplements for low serum ferritin seems to be effective with approximately 25% of children who have Periodic Limb Movement Disorder and ADHD.

With either treatment, the child gets a deeper, more restful night’s sleep, resulting in improvements in daytime concentration, behaviors, and work production. Furthermore, the ADHD-like characteristics often decrease, or in some cases, disappear completely. However, if the student has severe ADHD characteristics, sleep specialists are reporting that although the ADHD symptoms decrease with Neurontin, L-Dopa, or Clonadine, they usually do not disappear completely. Recent research by sleep specialists indicate that at least 25% of the children who have a diagnosis of ADHD may truly have Periodic Limb Movement Disorder or a combination of Periodic Limb Movement Disorder and Restless Legs Syndrome (RLS).

One sleep specialist reported that approximately 64% of children in a study with ADHD had Periodic Limb Movement Disorder and/or Restless Legs Syndrome (Picchietti et al, 1999). Although this estimate seems extremely high, it would be prudent to consult a sleep specialist with training in this area if a student has a diagnosis of ADHD, is oppositional, and scored high on the Periodic Limb Movement Disorder scale of the Sleep Disorders Inventory for Students. If your child / adolescent displays any of these symptoms of Periodic Limb Movement Disorder and you would like to screen your child / teen NOW, please click onto “Screen Child” below: