Do periodic leg movements differ between restless legs syndrome patients with low versus normal iron stores?

The association between restless leg syndrome and anxiety in Parkinson's disease: a case-control study

OBJECTIVE

To shed light on the association between restless leg syndrome (RLS) and anxiety in Parkinson's disease (PD) population.

METHODS

This was a case-control study including 129 PD participants with and without anxiety who presented to the Aerospace Center Hospital in Beijing, China. Anxiety was evaluated by using the Beck Anxiety Index score. RLS was assessed using the minimal diagnostic criteria of the International Restless Legs Study Group and RLS symptom frequency and treatment. We then examined the relationship between RLS and anxiety by logistic regression models and subgroup as well as interaction analyses.

RESULTS

The proportion of RLS in PD with anxiety was significantly higher in the PD without anxiety (p < 0.001). The multivariate logistic regression models indicated that PD participants with RLS had a 5.98-fold higher risk of anxiety in PD than those without RLS (OR, 6.98; 95% CI, 2.77-17.59). Subgroup analyses indicated that PD with RLS tended to be associated with a greater risk of anxiety in all stratified subgroups (adjusted ORs >1). Furthermore, the interaction analyses revealed no interactive role in the association between RLS and anxiety.

CONCLUSIONS

The present case-control study suggests that RLS is an independent risk factor for anxiety in PD patients. Early attention and targeted treatment for RLS may be necessary for mood management in PD. Larger prospective cohort studies are wanted to validate these findings.

CSF and serum ferritin levels in narcolepsy type 1 comorbid with restless legs syndrome

OBJECTIVES

To investigate whether cerebrospinal fluid (CSF) and serum ferritin levels differ between patients with narcolepsy type 1 (NT1) comorbid with restless legs syndrome (RLS) or periodic leg movements during sleep (PLMS), and patients with NT1 or controls without comorbid RLS or PLMS.

METHODS

Sixty-six drug-free patients with NT1 (44 males, age 38.5 years [14-81]) were enrolled, including 20 with RLS, 18 with PLMS index ≥15/h (six with both RLS and PLMS). Thirty-eight drug-free patients (12 males, age 22.5 years [12-61]) referred for sleepiness complaint, but without central hypersomnia, RLS, PLMS were included as controls. Clinical, electrophysiological and biological (CSF/serum ferritin, orexin [ORX]) data were quantified.

RESULTS

NT1 patients with and without RLS did not differ for age, gender, and body mass index (BMI). No between-group differences were found for CSF ferritin, ORX, and serum ferritin levels. No CSF ferritin, ORX, and serum ferritin level differences were found between NT1 patients with and without PLMS, or with RLS or PLMS versus not. CSF-ferritin levels were not different between NT1 and controls in adjusted analyses. CSF-ferritin levels in the whole population correlated positively with age, serum-ferritin, BMI, negatively with ORX, but not with PLMS index. In NT1, CSF-ferritin levels correlated with age and serum-ferritin but not with PLMS.

CONCLUSION

The absence of CSF ferritin deficiency in NT1 with comorbid RLS or PLMS indicates normal brain iron levels in that condition. This result suggests that the frequent association between RLS, PLMS, and NT1 is not based on alterations in brain iron metabolism, a pathophysiological mechanism involved in primary RLS.

Gender differences in clinical, laboratory and polysomnographic features of restless legs syndrome

Restless legs syndrome is a common neurological disorder with a clear female predominance. This study aims to evaluate gender differences in clinical, laboratory and polysomnographic features in patients with restless legs syndrome. For this retrospective analysis, 42 women and 42 men from the Innsbruck RLS database matched by age and therapy were included. Demographic data as well as different severity scales (IRLS, RLS‐6 and CGI) were evaluated. Laboratory parameters included several indicators of serum iron status. In all patients, polysomnography was performed according to the AASM guidelines, and periodic leg movements during sleep were scored according to the AASM criteria. IRLS, RLS‐6 and CGI revealed more severe symptoms in women (IRLS median [range]: 17.5 [0–35] versus 13.5 [0–32], p = 0.028; RLS‐6 median [range]: 18 [0–39] versus 12 [1–42], p = 0.014). Women had lower serum ferritin levels than men (median [range] in μg L⁻¹: 74 [9–346] versus 167 [15–389], p < 0.001). Twenty‐two women and eight men (53.7% versus 22.2%, p = 0.003) had ferritin values below 75 μg L⁻¹. Periodic leg movements during sleep indices were significantly lower in women than in men (median [range] in number per hr: 11.4 [0–62.5] versus 40 [0–154], p = 0.004, and 12.6 [0–58.5] versus 40 [0.5–208], p = 0.002, for night I and night II, respectively). Restless legs syndrome severity as measured by validated scales was worse in women, while periodic leg movements during sleep indices were higher in men. These results suggest a possible gender difference in phenotypical presentation of restless legs syndrome, manifesting with predominantly sensory symptoms in women and predominantly motor symptoms in men.