Are periodic leg movements during sleep (PLMS) responsible for sleep disruption in insomnia patients?

On the basis of polygraphic findings, it has been suggested that periodic l eg movements during sleep are not responsible for sleep impairment (Lugares i et al., 1972). However, for some authors it is an important cause of inso mnia (Guilleminault et al., 1975; Coleman, 1982). Thus, the relationship be tween periodic leg movements during sleep, sleep disruption and the complai nt of patients is particularly complex. We investigated the macro- and micr o-structure of sleep with and without leg movements in 10 PLMS patients com plaining of insomnia to clarify whether periodic leg movements are responsi ble for sleep disruption. The total sleep time without periodic leg movemen ts was significantly longer than sleep time with leg movements. Sleep time without leg movements was longer than sleep time with leg movements in stag e 2, slow wave sleep (SWS) and rapid eye movement (REM) sleep. Short lastin g awakenings were significantly more frequent during periodic leg movements associated sleep whilst long lasting awakenings were equally frequent duri ng sleep with and without periodic leg movements. The percentage of the fou r electroencephalogram (EEG) activities (delta, theta, alpha and spindles) did not show any significant difference between periodic leg movements asso ciated and not associated with sleep stages and total sleep time. The lack of significant differences in both the macro- and micro-structure of sleep and EEG activity content regarding the association with movements confirm t he hypothesis that periodic leg movements did not primarily cause sleep dis turbance.