Sleep laboratory studies in periodic limb movement disorder (PLMD) patients as compared with normals and acute effects of ropinirole

Periodic limb movement disorder (PLMD) occurs in a variety of sleep disorde rs and can cause insomnia as well as hypersomnia with daytime somnolence. T he aim of this study was to investigate 12 untreated PLMD patients as compa red with 12 normal controls and to measure the acute effects of 0.5 mg ropi nirole (Requip (R)) - a non-ergoline dopamine agonist - as compared with pl acebo. In three nights (adaptation, placebo, ropinirole night) objective an d subjective sleep and awakening quality were evaluated. In the target vari able 'periodic leg movements per hour of sleep' (PLM/(hTST)) PLMD patients showed an increased value of 42/h (normal 0-5/h) with a greater number of a rousals due to periodic leg movements (PLM) in sleep. They further demonstr ated an increased number of awakenings, sleep stage S1, S4, stage shifts an d decreased S2, but there were no significant differences concerning total sleep time, sleep efficiency (SE), subjective sleep quality and morning mea sures of mead, drive and drowsiness. However, measures of attention variabi lity, numerical memory, fine motor activity and reaction time performance w ere impaired. Ropinirole 0.5 mg was shown to significantly improve the inde x PLM/(hTST) by 64% and arousals due to PLM, increase spontaneous arousals, REM-latency, stage 2 and stage shifts and decrease SREM. In the morning at tention variability was attenuated and numerical memory augmented. Thus, ro pinirole improved some sleep architecture and early morning measures of per formance but specifically all PLM variables, which suggests a dopaminergic pathogenesis in PLMD. Copyright (C) 2001 John Wiley & Sons, Ltd.