Reduced Cerebral Perfusion of Putamen and Insular Cortex in Patients with Idiopathic Restless Leg Syndrome

Address for correspondence Seung Bong Hong, MD, PhD Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul 135-710, Korea Tel: +82-2-3410-3592 Fax: +82-2-3410-0052 E-mail: sbhong@skku.edu Objectives: To evaluate the cerebral perfusion pattern of idiopathic restless leg syndrome (RLS). Methods: We performed Tc-ethyl cysteinate dimer brain single-photon emission computed tomography (SPECT) in 36 drug-naive patients with RLS patients and 30 age-and gender matched normal cotrols during wakefulness. Their SPECT images underwent statistical parametric mapping analysis. Results: Mean age of patients and normal controls was 48.3 years and 80% of them were women. Most patients reported the sleep onset and maintenance insomnia due to RLS symtoms. Average duration of RLS was 10.5 years. Mean score of international RLS was 26.6, suggesting moderate to severe severity. They did not report daytime sleepiness (mean Epworth sleepiness scale, 7.0). All subjects underwent polysomnography, showing no definite obstructive sleep apnea syndrome. Seventeen of them (56.6%) had periodic leg movement during sleep (PLMS). Sleep quality was more deteriorated in patients than that in normal controls (increased sleep latency and arousal index, which resulted in reduced sleep efficiency). In RLS pateints, cerebral blood flow was decreased in the right putamen and insular cortex compared to normal controls (uncorrected p<0.005). There was no brain region showing increased cerebral perfusion in patients. Regional cerebral perfusion was not correlated to any sleep parameter including PLMS index or movement arousal index. Conclusions: Reduced cerebral perfusion in putamen and insular cortex in RLS suggested functional abnormalities in motor circuit and sensori-motor modulation, which may be related to pathophysiology of idiopathic RLS. J Korean Sleep Res Soc 2012;9:10-14