Three hundred twenty patients with PD completed the written questionnaire during a 15-week period; however, 17 were subsequently excluded because the diagnostic criteria for PD were not met (n = 11), participation in blinded drug trials precluded an accurate medicine history (n = 4), or they were not available to complete or verify data (n = 2). There were 303 remaining patients. Restless legs syndrome, as determined by affirmative response to 4 written questions, was initially reported by 83 of 254 patients who initially completed all 4 written questions. After all these patients were interviewed, and strict RLS criteria were applied, RLS was excluded in 28 of the original 83 "positive RLS diagnosis" cases. Patients who reported RLS symptoms in the written questionnaire, but were not believed to actually have RLS, usually had nocturnal dystonia, akathisia, or painful neuropathy. Subsequent interviews with patients with PD who did not initially report RLS on the written questionnaire added 8 additional patients to the PD/RLS group. Therefore, the final number of patients believed to have RLS was 63 (20.8%) of the 303. Only 16 (5.3%) of these 303 patients had a previous diagnosis of RLS. Of the 63 patients believed to have RLS, 11 reported a positive family history of RLS (Table 1). Parkinson disease symptoms preceded RLS symptoms in 35 (85%) of 41 patients (χ21 = 20.5, P<.001), but in the other 22 patients, this could not be reliably recalled by the patient. The presence of RLS did not correlate with any factor (duration of PD, age, Hoehn and Yahr stage, sex, dementia, use of levodopa, use of dopamine agonists, history of pallidotomy, or history of deep brain stimulation). Furthermore, RLS was not associated with higher Epworth Sleepiness Scale scores in this population (11.3 ± 6.3 vs 11.0 ± 5.6, PD/RLS group vs PD only group). A separate analysis showed that ferritin levels were lower in the PD/RLS group compared with the PD only group (t59 = 2.6, P = .01) (Table 1).