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.

Study Overview

• Status: Recruiting
• Conditions: Restless Legs Syndrome
• Intervention / Treatment: Other: Screening for symptoms of restless leg syndrome

Detailed Description

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.

• Study Type: Observational
• Enrollment (Estimated): 310

Contacts and Locations

• Study Contact: Name: Jindapa Srikajon, Doctor of Medicine; Phone Number: +66875932929; Email: jindapas@hotmail.com

Study Locations

• Thailand
  • Bangkok, Thailand, 10700
    • Recruiting
    • Siriraj Hospital, Mahidol University
    • Contact: Jindapa Srikajon, MD.; Phone Number: +66875932929; Email: jindapas@hotmail.com
  • Bangkok, Thailand, 10310
    • Recruiting
    • Siriraj Hospital, Mahidol University
    • Contact: Wattanachai Chotinaiwatttarakul, Doctor of Medicine; Phone Number: +6624197777; Email: exchot@yahoo.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Patients with Parkinson's disease aged from 18 to 80 years who met the UK Parkinson's Disease Society Brain Bank Diagnostic Criteria. The patients must regularly visit the movement disorders clinic at least 2 times per year.

Description

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.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients with parkinson's disease	Other: Screening for symptoms of restless leg syndrome; The patients will be screened for restless leg syndrome by clinical questioning.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
The prevalence of restless leg syndrome in patients with Parkinson's disease	At the time of recruitment

Secondary Outcome Measures

Outcome Measure	Time Frame
Clinical characteristics of Parkinson's disease patients with restless leg syndrome	At the time of recruitment

Collaborators and Investigators

• Sponsor: Siriraj Hospital
• Investigators: Principal Investigator: Jindapa Srikajon, Doctor of Medicine, Siriraj Sleep Center, Faculty of Medicine, Siriraj Hospital, Mahidol University

Study record dates

Study Major Dates

• Study Start (Actual): December 1, 2024
• Primary Completion (Estimated): October 31, 2026
• Study Completion (Estimated): November 30, 2026

Study Registration Dates

• First Submitted: November 10, 2024
• First Submitted That Met QC Criteria: November 10, 2024
• First Posted (Actual): November 12, 2024

Study Record Updates

• Last Update Posted (Actual): May 15, 2025
• Last Update Submitted That Met QC Criteria: May 12, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: prevalence; parkinson's disease; restless leg syndrome; Thai population
• Additional Relevant MeSH Terms: Synucleinopathies; Aberrant Motor Behavior in Dementia; Neurologic Manifestations; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Mental Disorders; Pathologic Processes; Behavioral Symptoms; Disease; Neurobehavioral Manifestations; Neurodegenerative Diseases; Sleep Wake Disorders; Movement Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Parkinsonian Disorders; Basal Ganglia Diseases; Dyskinesias; Psychomotor Disorders; Parasomnias; Syndrome; Parkinson Disease; Psychomotor Agitation; Restless Legs Syndrome
• Other Study ID Numbers: 762/2567(IRB1)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No