Recruiting · registry status

Why some tremor responds to levodopa and some does not

This study investigates brain mechanisms behind different treatment responses in Parkinson's tremor.

Testing a treatment or activity · Study reference: NL-OMON40810

Plain-language introduction written with AI from the registry; not independently checked by a clinician. Read the original details below ↓

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Start (reported date): 2014-06-06

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No results summary has been confirmed in the registry records we imported. See connected papers below; we keep checking after recruitment ends.

Changes we have recorded

2026-10-11 — recruiting

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Papers connected to this study

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Sex eligibility reported by registry: Not reported

Inclusion criteria: - Idiopathic Parkinson*s disease according to UK brain bank criteria. - Presence of a clear resting tremor of at least one arm (UPDRS tremor-score 2 or more). - Dopaminergic therapy with a clear clinical response of non-tremor symptoms (bradykinesia, rigidity). - Milde tot moderate disease severity (Hoehn and Yahr 1-3). Exclusion criteria: - Neurological or psychiatric co-morbidity (e.g. stroke, depression). - Severe head tremor or dyskinesias. - Cognitive impairment (MMSE < 26). - General MRI exclusion criteria (e.g. pacemaker, implanted metal parts, deep brain stimulation, claustrophobia). - Co-medication associated with elongated QT-time. - Pregnancy. - Age < 25 years.

Full study name & original research details

Official study title

Explorations into the cerebral mechanisms of dopa-responsive and dopa-resistant Parkinson*s resting tremor - Dopa-responsive vs. dopa-resistant tremor in PD

Short title used by the registry

Explorations into the cerebral mechanisms of dopa-responsive and dopa-resistant Parkinson*s resting tremor

Original description

Intervention: All Parkinson patients (n=80) will be tested without dopaminergic medication (their own medication stopped for at least 12 hours). On one day they will receive a placebo (with 10 mg Domperidon), on the other day dopaminergic medication (250 mg Levodopa-Benserazide and 10 mg Domperidone). The goal of the intervention is to distinguish patients with a dopamine-responsive tremor from patients with a dopamine-resistant tremor, and to test if tremor-related brain regions in both groups are dopamine-responsive. This is not a randomized research. The controls will not get an intervention. Primary outcome: The primary outcome measure of this study is the difference in tremor-related brain activity at rest, during a motor task, and during a simple cognitive task, with and without dopaminergic therapy, between Parkinson patients with dopa-resistant and dopa-responsive tremor. Secondary outcome: Secondary outcome measures are the difference in GABA concentrations in the thalamus, structural integrity of the brain stem (DTI), and functional connectivity between basal ganglia and the cerebello-thalamo-cortical circuit, between both Parkinson groups and healthy controls. We will also compare tremor characteristics (frequency, distribution over the body) between Parkinson patient with dopa-responsive and dopa-resistant tremor, and we will compare cognitive performance on dopamine-sensitive and dopamine-insensitive behavioral tasks.

Conditions reported: Parkinson's disease tremor;10028037

Registry records for this study

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NL-OMON · NL-OMON40810 ↗ — Recruiting; WHO ICTRP processed 2024-06-11; checked 2026-10-13

Study type: Interventional
Interventions: All Parkinson patients (n=80) will be tested without dopaminergic medication (their own medication stopped for at least 12 hours). On one day they will receive a placebo (with 10 mg Domperidon), on the other day dopaminergic medication (250 mg Levodopa-Benserazide and 10 mg Domperidone). The goal of the intervention is to distinguish patients with a dopamine-responsive tremor from patients with a dopamine-resistant tremor, and to test if tremor-related brain regions in both groups are dopamine-responsive. This is not a randomized research. The controls will not get an intervention.
Phases: Not reported
Sponsor: Universitair Medisch Centrum Sint Radboud
Start date reported by registry: 2014-06-06 (reported)

Registry updated: Not reported · Status last verified by the registry submitter: Not reported

Registry records retrieved 2026-10-13 (UTC). Individual records may have older updates. Recruitment and eligibility must be confirmed with the study team.

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Study locations

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Facility not reported

Netherlands

Status not reported

The original descriptions and participation rules come from the registry. Participation is voluntary and does not guarantee benefit.