PLMs are also known as nocturnal myoclonus. Sometimes they are also referred to as periodic limb movements because they can also occur in the arms. Some laboratories will place electrodes on the arms as well. It is important to remember that PLMs occur during sleep. The leg movements can result in several arousals or awakenings during the night, thus causing a complaint of insomnia or excessive daytime sleepiness.
Patients are usually unaware of the movements because they occur before the awakenings.
Due to the fragmentation of sleep, patients often awaken in the morning feeling tired and unrefreshed. It is as though they have been merely been catnapping between their leg movements. Restless legs syndrome is a disorder which interferes with sleep onset . While trying to fall asleep, a person suffering from RLS will experience sensations in their legs which can only be relieved by movement. The Centre for Sleep and Dream Studies, Ottawa, Canada.