Prevalence and Characteristics of Restless Leg Syndrome in Thai Patients With Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by pathologic intraneuronal alpha-synuclein-positive Lewy bodies and neuronal cell loss. The cardinal clinical symptoms and signs of PD are bradykinesia, rigidity, tremor, postural instability, and freezing attacks. The prevalence of PD increases with age, affecting 1-2% of the population over the age of 65 years, and 3% of those over 85 years.

Restless legs syndrome (RLS) represents disturbing symptoms in lower limbs that lead to the urge to move, occurring in rest periods. Movements can partially or completely relieve these abnormal feelings. In 2014, the International RLS Study Group (IRLSSG) established five mandatory criteria for the diagnosis of RLS. Several studies supported that RLS and PD may share pathophysiological mechanisms.

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Key information

Conditions

Restless Legs Syndrome Basal Ganglia Diseases Brain Diseases Central Nervous System Diseases Dyssomnias Mental Disorders Movement Disorders Nervous System Diseases Neurodegenerative Diseases Parasomnias Parkinson Disease Parkinsonian Disorders Sleep Disorders, Intrinsic Sleep Wake Disorders Synucleinopathies

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Siriraj Hospital, Mahidol University, Bangkok, Thailand

About this study

In the general population, the prevalence of RLS was reported to be up to 10%. In Parkinson's disease (PD), the mean prevalence of RLS was 15.74%. Cross-sectional studies show a variable prevalence of RLS in PD patients ranging approximately from 0 to 50%. In case-control studies, the mean prevalence of RLS was higher in people with PD (12%) vs. healthy controls (5.1%). One four-year longitudinal study reported an increase in RLS prevalence from 4.6% to 16.3% along with disease progression. Interestingly, RLS was found to have various prevalence depending on geographic areas: highest in European populations (5% to 12%), intermediate in Asian countries (1% to 8%), and lowest in African countries (<1%).

In Patients with Parkinson's disease, diagnosis of RLS is challenging due to multiple confounders such as motor fluctuations, akathisia, etc. It is crucial to pick up RLS in Parkinson's disease and properly manage the symptoms. RLS not only causes impaired quality of life but also possibly leads to cardiovascular consequences. RLS was associated with statistically significantly less future cardiovascular risk in RLS patients with treatment than in those without treatment. Nevertheless, there have been no consistent studies of this association in Parkinson's disease yet.

From the literature review, very few data have been stated regarding RLS in Thai patients with Parkinson's disease. There was only one study focusing on the prevalence of RLS in Thailand, in which the prevalence of RLS in Thai Parkinson's patients was only 1.6%. According to the author, there were possible explanations for the low prevalence. Firstly, they only included participants with idiopathic RLS. Secondly, high doses of dopaminergic agents might obscure the symptoms of RLS in those patients with Parkinson's disease. Moreover, they screened patients with the Cambridge-Hopkins diagnostic questionnaire which had not been validated in Thai people yet. For all these reasons, we believe that the prevalence of RLS in Thai patients with Parkinson's disease would be different with another methodology. We also would like to know more about the characteristics of RLS in Thai Parkinson's disease patients, which might help improve RLS detection in this population.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Patients with Parkinson's disease aged from 18 to 80 years who met the United Kingdom Parkinson's Disease Society (UKPDS) Brain Bank Diagnostic criteria.

Exclusion criteria

Patients with atypical or secondary parkinsonism.
Patients with Mini-mental status exam (MMSE) less than 24 of 30.
Patients with secondary causes of restless leg syndrome including end-stage renal disease, iron deficiency anemia and pregnancy.

Treatment and study plan

Screening for symptoms of restless leg syndrome

Other

The patients will be screened for restless leg syndrome by clinical questioning.

Primary outcomes

The prevalence of restless leg syndrome in patients with Parkinson's disease

Time frame: At the time of recruitment

Secondary outcomes

Clinical characteristics of Parkinson's disease patients with restless leg syndrome

Time frame: At the time of recruitment

Study contacts

Contact information is provided by the study sponsor or research team.

Jindapa Srikajon, Doctor of Medicine

CONTACT

[email protected]

+66875932929

Sponsors and collaborators

Lead sponsor

Siriraj Hospital

Other

Registry information

Important dates

Study start: 2024
Primary completion: 2026
Study completion: 2026
First posted: Nov 12, 2024
Registry last updated: May 15, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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