Clinical characteristics of leg restlessness in Parkinson's disease compared with idiopathic Restless Legs Syndrome

https://doi.org/10.1016/j.jns.2015.07.008Get rights and content

Highlights

  • RLS was more asymmetrical and related to dominant Parkinsonism in PD/RLS patients.

  • PD/RLS + patients had more severe Parkinsonism compared with PD/RLS- patients.

  • Less dopaminergic medication was used in PD/RLS + than PD/RLS- patients when RLS onset.

  • Opposite seasonal pattern was observed in PD/RLS compared with iRLS.

  • PD/LMR had less severe symptoms of leg discomfort and Parkinsonism compared to PD/RLS.

Abstract

Objective

There is limited data on motor restlessness in Parkinson's disease (PD). Here we evaluate for clinical differences between cohorts of idiopathic Restless Legs Syndrome (iRLS), PD patients with leg restlessness, and PD with RLS.

Methods

We examined 276 consecutive PD patients for leg restlessness symptoms, we compared clinical features of PD patients with RLS, PD patients with leg restlessness but not meeting RLS criteria, PD patient without RLS and iRLS.

Results

A total of 262 PD patients who satisfied the inclusion criteria were analyzed. After excluding 23 possible secondary RLS or mimics, 28 were diagnosed with RLS and 18 with leg motor restlessness (LMR). Compared with iRLS patients, PD patients with RLS or LMR had older age of RLS/LMR onset, shorter duration of leg restlessness, less positive family history, different seasonal trends and more unilaterality of leg restlessness symptom (P < 0.01) which were often in accordance with dominant Parkinsonism side and related with Parkinsonism severity. PD patients with RLS/LMR had lower daily dosage (P < 0.01) and shorter duration (P < 0.05) of dopaminergic medication when RLS/LMR symptom onset than PD without leg restlessness. PD with LMR had less severe Parkinsonism (P < 0.05) and leg restlessness (P < 0.01) symptoms than PD with RLS.

Conclusion

Clinical characteristics of PD patients with RLS and LMR were different from iRLS, differentiating these various subtypes can facilitate optimal treatment.

Introduction

Restless Legs Syndrome (RLS) and Parkinson's disease (PD) are common neurological disorders that both respond to dopaminergic therapy. Previous prevalence studies showed an association of the two conditions with various reported incidence that varied from 0% to 50% often considered as due to ethnic differences [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18]. However, most of the previous studied didn't exclude secondary RLS [3], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [16], [17], [18]. Leg motor restlessness (LMR), which is recently regarded as a kind of “focal akathisia” [19], was described in 2011 as a desire to move the limbs usually associated with paresthesias/dysesthesias but not fulfilling the full RLS criteria [2]. LMR can be a kind of RLS mimic since lower limb restlessness and/or sensory symptoms are frequent manifestations during off periods in PD and are part of the spectrum of levodopa-related fluctuations [20]. Dopaminergics can also affect RLS presentation with controversial effects of either masking or augmenting possible coexisting RLS symptoms. Current literature on the clinical profile of “genuine” leg restlessness in PD and possible overlap confounders is limited, while to discriminate these different conditions is of great importance due to different subsequent therapeutic options. With this background, we studied the clinical spectrum of leg restlessness including RLS and LMR in PD patients and further compared with idiopathic RLS (iRLS) patients to explore the relationship between RLS and PD and to explore if RLS in PD is secondary to Parkinsonism related factors or anti-Parkinsonism medications in a Chinese cohort of patients.

Section snippets

Subjects

Consecutive outpatients with a diagnosis of PD were recruited from Parkinson's disease and Movement Disorders Clinic in Department of Neurology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine between Sep 2012 and Sep 2014. We also collected iRLS patients between Nov 2013 and Sep 2014. PD was diagnosed according to the United Kingdom PD Society Brain Bank clinical diagnostic criteria [21]. RLS was diagnosed when a patient met all International Restless Legs Syndrome

Results

276 PD patients agreed to participate in the study, 6 were excluded due to cognitive impairment, and 8 were excluded due to atypical Parkinsonism during subsequent follow-up, leaving 262 eligible PD patients, including 135 male subjects (51.5%) and 127 female subjects (48.5%). The average age was 68.3 ± 10.2 years old. Mean duration of PD was 4.8 ± 4.2 years and mean age of PD onset was 63.4 ± 10.8 years.

We also recruited 61 patients diagnosed with RLS, 8 of whom were excluded due to secondary causes.

Discussion

Most of the previous cross-sectional studies on RLS in PD didn't exclude secondary RLS and did not meet the updated RLS diagnostic criteria [3], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [16], [17], [18]. In this study, we had excluded known causes of other secondary RLS according to comprehensive examinations and also excluded patients taking certain medicines to induce possible RLS mimic symptoms. Thus, RLS patients diagnosed in our study met the fifth essential criterion added

Conclusion

Leg restlessness in PD should be discriminated carefully due to possible confounders including LMR, which maybe related with a relatively decreased dopamine level in PD. Clinical features of PD patients with RLS and LMR are different from those of iRLS in many aspects. Our results suggest that RLS in PD is correlated with severity of Parkinsonism rather than ongoing dopaminergic treatment. PD patients with LMR had less severe PD and RLS symptoms than PD patients with RLS. Differentiating these

Conflict of interest

We declare no conflict of interest.

Acknowledgments

This work was supported partially by National Basic Research Program of China (973 Program) (2011CB707506), National Natural Science Foundation of China (81171205, 81371410), West China Psychiatry Association Foundation (WCPAfund2014-1) and the Biomedical Multidisciplinary Program of Shanghai Jiao Tong University (YG2014MS31).

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    These authors contributed equally to this work.

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