Comparison of motor pattern of periodic limb movements in patients with restless legs syndrome and obstructive sleep apnea syndrome

Background/aim: Periodic limb movements (PLMs) are repetitive and stereotypical movements of the lower extremities that occur during sleep. The purpose of this study was to analyze the leg muscle activity patterns in PLMs seen in restless legs syndrome (RLS) and obstructive sleep apnea syndrome (OSAS). Materials and methods: In this study, 1260 PLMs from 4 patients with RLS and 4 patients with OSAS were analyzed. The spreading and frequency characteristics of the gastrocnemius, medial hamstring, and vastus muscles were examined separately for each muscle in addition to the tibialis anterior muscle already included in the standard polysomnography recording. Results: A greater number of PLMs (57.34%) were observed in patients with RLS. A greater number of apnea-related PLMs (59.83%) were observed in patients with OSAS. The number of PLMs with spreading characteristics was higher in both patient groups. In both groups, the first muscle to contract was most frequently the tibialis anterior. Analysis of the subsequent contraction patterns showed no regular course in RLS and OSAS patients. Conclusion: PLMs may occur with a nonstereotypical muscle spreading pattern generated by different, independent, and, most frequently, unsynchronized spinal generators.