Restless Legs Syndrome

Diagnosis

Supportive Clinical Features

In situations with diagnostic uncertainty, the supportive clinical features (Table 2) may assist the clinician in diagnosing cases of RLS. These features are not required for the diagnosis of RLS, but their presence does lend reinforcement to the diagnosis.

Table 2

Supportive Clinical Features of Restless Legs Syndrome

More than 50% of patients with primary RLS have affected family members.

A positive response to dopaminergic therapy is almost universal.

As many as 85% of people with RLS have periodic limb movements during wakefulness or sleep.

Modified from Allen RP, Picchietti D, Hening WA, Trenkwalder C, Walters AS, Montplaisir J. Restless legs syndrome: diagnostic criteria, special considerations, and epidemiology. A report from the restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med 2003;4(2):101-119.

A variety of research studies have verified the clinical impression that approximately 50% of patients with RLS have a family history of the disorder. A person with RLS is three to six times more likely to have another family member with RLS than is someone without RLS.9, 11, 74, 76, 136

Another clinical feature of both primary and secondary RLS is the almost universal response to dopaminergic therapy. The vast majority of people with RLS will have an initial positive response to treatment with either levodopa137-144 or a dopamine receptor agonist. If the patient's symptoms do not respond to dopaminergic therapy, the diagnosis may need to be reevaluated.

More than 85% of people with RLS have periodic limb movements during sleep (PLMS), during wakefulness, or during both sleep and wakefulness. Montplaisir and his colleagues have studied the prevalence of both arm and leg movements during sleep, using polysomnography (which in a typical clinical scenario does not include the assessment of arm movements), and during wakefulness, using the SIT.88