Letter to the Editor

Effective treatment of restless legs syndrome by safinamide in Parkinson's disease patients

Sleep-related movement disorders are a heterogeneous category including several disorders. Among them, restless legs syndrome (RLS) stands out for its high prevalence. Regarding RLS treatment, non-pharmacological treatment should be considered in the first instance, as well as iron replacement therapy, which has been demonstrated to be safe and effective in RLS. In recent years, the role of dopaminergic agonists has changed because of the risk of developing augmentation of RLS symptoms. Hence α2δ ligands are preferred. In refractory cases or cases of augmentation, opioids can be used. Regarding periodic limb movement disorder, treatment decision-making is comparable with RLS. Treatments for other sleep-related movement disorders are also discussed in this article.

Rapid Eye Movement sleep behavior disorder (RBD) is characterized by dream enactment and loss of muscle atonia during REM-sleep. RBD as a premotor feature occurred souvent in patients who develop Parkinson’s disease. The glutamatergic, glycinergic, and GABA-ergic systems appear to play a crucial role in the pathogenesis of RBD.

The present exploratory longitudinal cross-over study aimed to observe the effect of safinamide on RBD symptoms. Thirty patients with PD and RBD were randomized into two groups (15 subjects each), those that received for a period of 3-months safinamide (50 mg/die) in addition (Group A + ) or in absence (Group B − ) to the usual antiparkinsonian therapy. Patients exploring the clinical and video-polysomnographic changes occurred during this pharmacological therapy.

Twenty-two of 30 patients reported clear improvement in symptoms during safinamide treatment, and 16 were absolutely free from clinical RBD-symptoms at the end of the treatment. Eight patients reported slight improvement in RBD-symptoms. In 6/30 patients no substantial improvement was recorded about clinical RBD-symptoms had frightening dreams or from the bed after 1-week of treatment. In addition, after safinamide, the mean UPDRS-II and III scores decreased, while PDSS-2 score indicating an improvement in both motor symptoms and nocturnal sleep features. A significant reduction of sleep behavior disorder by questionnaire-Hong Kong-score (RBDQ-HS), mainly for two individual RBDQ-HK-items (dream related movements and failing out of bed) was registered.

This pilot study indicated that safinamide is well tolerated and improves RBD-symptom in parkinsonian.