The definition and scoring criteria for periodic leg movements (PLM) during sleep have not changed since 1990  and 1993  and are substantially based on the work carried out by Coleman et al. in 1982 . The aim of the Atlas and Scoring Rules  was to provide recommendations for the correct recording of motor events, the use of standard terminology and the definition of some common rules to quantify PLM. However, the current standard for recording sleep is based on computerized technology, and new pathologies have been recognized to be associated with PLM during sleep (PLMS), different motor patterns have also been detected and new sophisticated methods of signal analysis have changed our understanding of the impact of PLM on sleep patterns. In particular, the analysis of the electromyogram (EMG) signal and of the periodicity of the phenomenon provides different methods for the evaluation of muscle activity in normal and pathological sleep.
PLMS Reference Paper