Rahimdel et al. Materials and Methods In our study, which began in June 2010 and lasted until November 2010, initially 68 patients were en- rolled with diagnosis of primary RLS based on IRLSSG. The trial was an experimental study and was registered in IRCT (Code: Irct2011103015943n1). All patients passed the full exams by two neurologists. None of examiners had any knowledge about the col- league's diagnosis. Patients diagnosed as primary RLS by two neurologists were enrolled. The inclusion criteria were (i) Severity of symptoms at least to be moderate (point >10 based on IRLS) and (ii) Patients to be in primary RLS category. All patients under- went routine laboratory exams too. After confirma- tion, primary cases were enrolled. Eight patients were omitted during the study because of low compliance and insufficient data feedback and finally 60 patients passed the clinical trial successfully. All patients signed an informed consent and were informed for steps of clinical trial and the probable side effect of the drug. The trial was based on 3 periods of drug prescription (every period of the last one month) with one month wash out period. Only the designer of study was aware of the order of drug administration and the others (neurologists, drug administrators and patients) were blind to the pattern and order of drug administration. Table 2 shows the steps of trial. Placebo, 50 and 200 mg selenium were prescribed as capsules in equal shape and form. Patients and in- vestigators did not know about the materials inside the capsules. The capsules were delivered to patients in three distinctive same packages with information insides, including start and end of the data. During the trial, all patients were questioned regularly about the consumption and dose effects of the medication and were encouraged to use the drugs precisely. After the end of each month of drug consumption, question- naires were completed and asked them to describe the severity of the disease and any side effects of the drug. At least 10 declines in scale were considered as an appropriate response. All statistical analyses were performed using SPSS software (version 11.5, Chica- go, IL, USA).The results were shown as mean±SD. In every period, before-after scores of males and females were analyzed separately by using nonparametric Table 2: Steps of trial State Placebo Duration One month 16 Wilcoxon test. Comparison of the effect of the drug in every period between males and females was as- sessed by Mann-Whitney test. All before-after scores in the three groups were compared together by Freedman test. P-value of < 0.05 was considered as statistically significant. Results Sixty patients (34 females, mean age: 54±11.4 and 26 males, mean age: 49±12.3) were enrolled. Table 3 shows the rate of placebo and selenium efficacy. Rate of improvement (decline IRLS score>10) was signifi- cantly higher in selenium than placebo group. Im- provement rate between 50 and 200 mg of selenium consumption was not significantly different. Table 3: Score decline comparison between place- bo and 50 and 200 µg of selenium. Score Placebo 50 µg sele- 200 µg se- decline No. (%) nium lenium No. (%) No. (%) 10-15 11 (18.3) 27 (45) 30 (50) 15-20 0 4 (7) 6 (10) Total 11 (18.3) 31 (52) 36 (60) Patients score before and after treatment with pla- cebo, 50 and 200 µg of selenium were shown in Table 4. There were no significant differences between males and females in response to placebo, 50 and 200 µg of selenium (p values respectively=0.489, 0.473 and 0.446). Decline in score after treatment by 50 and 200 µg of selenium was significantly higher than pla- cebo group (Both p values were less than 0.001). Also difference between 50 and 200 µg of selenium was significant (p value=0.007). Discussion In our study, females were more afflicted by primary RLS than males (34 vs. 26).This may be due to sexual hormone effects, dietary regimen, psychologic and sleep problems in this gender. Also silent coincidence Washout One month 50 µg selenium One month Washout One month 200 µg selenium One month WWW.ircmj.com Vol 14 January 2012