Time structure of leg movement activity during sleep in attention-deficit/hyperactivity disorder and effects of levodopa

Objectives: To evaluate the leg movement (LM) time structure (periodicity and night distribution) during sleep in children with attention-deficit/hyperactivity disorder (ADHD) and their eventual changes after treatment with levodopa (L-DOPA). Subjects and methods: One group of ADHD patients (n= 18) and another group of normal controls (n= 17) were recruited; those with ADHD were randomized to L-DOPA or placebo therapy. At baseline (both groups) and after therapy (only patients) subjects underwent full-night polysomnography (PSG) and the leg motor pattern was evaluated with advanced tools of analysis particularly able to detect and describe LM time structure (periodicity and distribution). Results: With respect to controls ADHD children showed prolonged sleep latency, increased number of stage shifts, awakenings, and percentage of sleep stage 1. Arousal index was higher in ADHD and also their PLMS index was slightly but considerably higher than controls; however, their periodicity was low and not different from controls. Only sleep latency was significantly reduced by L-DOPA treatment with all the other parameters (sleep scoring and LM activity) remaining substantially unmodified. Conclusions: LMs during sleep in children with ADHD do not show a highly periodic character and are not considerably modified by L-DOPA treatment; this finding has potential implications for drug treatment that might target the most prominent changes observed in our study including arousals and sleep structure disruption.