Reduced daytime intramuscular blood flow in patients with restless legs syndrome/Willis-Ekbom disease

Aim: The aim of this study was to examine possible signs of impairment of the microcirculation in the lower extremities of female patients suffering from primary restless legs syndrome (RLS)/Willis-Ekbom disease. Methods: This study was performed in eight female patients, mean age 48 years (range 21-65), diagnosed with primary RLS but otherwise healthy. Eight healthy female control subjects, mean age 47 years (range 27-64), were also included in the study. Laser Doppler flowmetry was used to determine intramuscular blood flow by placing an optical single fiber in the tibialis anterior muscle belly. The studies were performed between 08.00 and 10.00 hours and 20.00 and 22.00 hours. Blood flow was expressed in perfusion units. Results: The median intramuscular blood flow in the RLS patients' tibialis anterior muscles, recorded from both legs, was significantly higher in the morning, at 17.9 perfusion units, than in the evening, at 12.1 perfusion units (P = 0.004). Corresponding values for the healthy controls were 13.1 perfusion units and 12.0 perfusion units, a non-significant difference. The relative fold changes of microcirculation in the RLS group compared to healthy age-matched controls were 0.7 +/- 0.3 and 1.1 +/- 0.6, respectively (P = 0.04). Conclusion: Our results suggest that in female patients with primary RLS, the microcirculation in the tibialis anterior muscle is higher in the morning compared with in the evening.