Clinical characteristics of leg restlessness in Parkinson's disease compared with idiopathic Restless Legs Syndrome
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).
References (29)
- et al.
Restless legs syndrome in Parkinson's disease
Parkinsonism Relat. Disord.
(2014) - et al.
A study of the prevalence of restless legs syndrome in previously untreated Parkinson's disease patients: absence of co-morbid association
J. Neurol. Sci.
(2011) - et al.
Prevalence and profile of restless legs syndrome in Parkinson's disease and other neurodegenerative disorders: a case–control study
Parkinsonism Relat. Disord.
(2013) - et al.
Case–control study of restless legs syndrome and quality of sleep in Parkinson's disease
J. Neurol. Sci.
(2008) - et al.
Restless legs syndrome in Korean patients with drug-naive Parkinson's disease: a nation-wide study
Parkinsonism Relat. Disord.
(2013) - et al.
Association of pain, Parkinson's disease, and restless legs syndrome
J. Neurol. Sci.
(2013) - et al.
Restless legs syndrome in Parkinson's disease
J. Neurol. Sci.
(2002) - et al.
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) - et al.
Restless legs syndrome/Willis–Ekbom disease diagnostic criteria: updated International Restless Legs Syndrome Study Group (IRLSSG) consensus criteria—history, rationale, description, and significance
Sleep Med.
(2014) - et al.
Clinical characteristics of restless legs syndrome in patients with Parkinson's disease
J. Neurol. Sci.
(2006)
What features differentiate unilateral from bilateral restless legs syndrome? A comparative observational study of 195 patients
Sleep Med.
Seasonal trends in restless legs symptomatology: evidence from Internet search query data
Sleep Med.
Sensations in restless legs syndrome
Sleep Med.
Increased risk of leg motor restlessness but not RLS in early Parkinson disease
Neurology
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These authors contributed equally to this work.