Clinical, polysomnographic, and genetic characteristics of restless legs syndrome: a study of 133 patients diagnosed with new standard criteria.

One hundred thirty-three cases of restless legs syndrome (RLS), diagnosed with criteria recently formulated by an international study group, were studied by questionnaire and with all-night polysomnographic recordings. Results show that RLS starts at a mean age of 27.2 years and before age 20 in 38.3% of patients. Symptoms often appear in one leg only and also involve upper limbs in about half of all cases. Most patients (94%) report sleep-onset insomnia or numerous nocturnal awakenings due to RLS symptoms. A strong relationship was found between these complaints and polysomnographic findings; increasing sleep latency and number of awakenings and decreasing sleep efficiency were associated with worsening symptoms. Periodic leg movements in sleep (index > 5 movements/h sleep) were found in 80.2% of patients. This study shows that this percentage is increased when 2 recording nights are considered (most severe score). Eighty patients of 127 (63%) reported the presence of RLS in at least one of their first-degree relatives. In these families, 221 of 568 first-degree relatives (39%) were reported by the patients to be affected with RLS.