REBUTTAL FROM DR. WALTERS

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Dr. Mahowald is correct in pointing out that restless legs syndrome is a clinical diagnosis and that monitoring of PLMs while the patient is awake or asleep is not essential to make the diagnosis. He is incorrect in stating that PLMs can be distinguished from the other movement disorders in sleep by history alone.

I point out that autonomic arousal (fast pulse and transient rises of blood pressure on the order of 23%) may accompany PLMs. There is new evidence that patients with restless legs syndrome have a higher prevalence of hypertension (OR 1.5; 95% CI, 0.9-2.4) and heart problems (OR, 2.5; 95% CI, 1.4- 4.3) (1). Because the majority of patients with restless legs syndrome have PLMs in sleep, transient rises in blood pressure associated with the PLMs in sleep may contribute to heart disease and perhaps stroke when superimposed on an already elevated blood pressure. This model is not dissimilar to that proposed to explain the increased prevalence of cardiovascular and cerebrovascular disease in sleep apnea. Further research is needed to confirm that transient hypertension is associated with PLMs in sleep in larger numbers of patients.

Dr. Mahowald quotes articles stating that there is no relationship between PLMs in sleep and depression. I quote an article to the contrary. In a long-term open label study we treated children with attention-deficit hyperactivity disorder who also had PLMs in sleep and restless legs syndrome with L-DOPA (2). This medication has previously been shown in many studies to improve PLMs in sleep and restless legs syndrome. In our study attention-deficit hyperactivity symptoms also improved and stayed improved for a period of at least 3 yr. We have most recently shown that adults with restless legs syndrome are more likely to report symptoms of attention-deficit hyperactivity disorder than control subjects (3). Although there are many possible explanations for these data, one explanation could be that the sleep disruption from the PLMs in sleep and the prevention of sleep from the PLMs in wakefulness contribute to the symptoms of attention-deficit hyperactivity disorder. Again, this is not dissimilar to the evidence linking sleep apnea to attention-deficit hyperactivity disorder.

	References

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1. Ulfberg J, Nystrom B, Carter N, Edling C. Prevalence of restless legs syndrome among men aged 18-64 years. An association with somatic disease and neuropsychiatric symptoms. Mov Disord 2001. (In press)

2. Walters AS, Mandelbaum DE, Lewin DS, Kugler S, England SJ, Miller M, Dopaminergic Therapy Study Group. Dopaminergic therapy in children with restless legs/periodic limb movements in sleep and ADHD. Pediatr Neurol 2000;22:182-186.

3. Wagner ML, Walters AS, Fisher BC, Lyall J, Rana A, Lebrocq C, et al. The prevalence of attention deficit hyperactivity disorder and oppositional defiant disorder symptoms in adults is greater in RLS patients than in controls. Neurology 2001;56(Suppl 3):A4.