Sleep laboratory studies in restless legs syndrome patients as compared with normals and acute effects of ropinirole. 2. Findings on periodic leg movements, arousals and respiratory variables

Abstract

The restless legs syndrome (RLS) is a common sensorimotor disorder which leads to severe sleep disturbances and showed a prevalence of 7.9% in our sleep laboratory. The aim of this study was to investigate periodic leg movements (PLM), arousal and respiratory variables in 12 untreated RLS patients and to measure the acute effects of 0.5 mg ropinirole, a nonergoline dopamine agonist, as compared with placebo. In the target variable PLM/h of total sleep time (PLM/h TST), RLS patients showed an increased value of 40/h (normal 0-5/h). Further, we found an increased number of PLM (368), PLM/h of time in bed (49/h), PLM/h of REM sleep (11), PLM/h of non-REM sleep (46) and PLM/h awake (61). The arousal index was also increased (32/h; normal 0-25/h), as were arousals due to PLM. In the confirmatory part of our descriptive data analysis, ropinirole 0.5 mg significantly improved, as compared with placebo, the index PLM/h TST by 75%. In the descriptive part, all the other PLM variables were improved as well. Arousals due to PLM decreased, while spontaneous arousals increased. Respiratory variables, which had a priori been in the normal range, showed a slight but significant improvement after the dopamine agonist. Thus, 0.5 mg ropinirole significantly improved the target variable PLM/h TST, along with objective and subjective sleep quality and morning noopsychic performance, as described in the preceding paper. Our data encourage further sleep studies including all above-mentioned variables in a larger group of RLS/PLM during sleep patients as well as long-term efficacy trials.