Exploring the Relationship Between L-dopa Responsiveness and Small Intestinal Microbiome in Parkinson's Disease

Inclusion criteria

• Males and females aged 50-85 years old at time of on-site visit. (ages 81-85 will be assessed on a per case basis by the principal investigator)
• Signed Informed consent.
• Willing & able to comply with study procedures (including SIMBA capsule ingestion) and have study assessments performed.
• Able to swallow a size-00 capsule (25mm length) in OFF state.
• Diagnosis of idiopathic PD (Clinically Probable PD), including documented levodopa responsiveness.
• Treatment with an immediate release levodopa formulation during the day at a stable dose for at least 2 months prior to enrollment.

Exclusion criteria

• Any risk of capsule non-excretion related to intercurrent gastrointestinal conditions.
• Use of any medications in the week prior to the on-site study visit, unless part of regular treatment, that could substantially alter gastrointestinal motor function.
• History of oropharyngeal dysphagia, or other swallowing disorder with a risk of capsule aspiration, e.g., SDQ score > 4.
• Any concomitant or previous treatment (<2 months from on-site study visit) with significant anti-inflammatory or immune suppressant medication, e.g., DMARDs, biologicals or systemic corticosteroids, except non-chronic PRN use of an NSAID and/or 5-ASA (mesalazine) treatment.
• Active cancer within 5 years.
• Clinically significant immune deficiency (according to Investigator's judgement).
• Antibiotic use (except for local use), ≤12 weeks prior to on-site study visit, or Fecal Microbiota Transplantation anytime in medical history.
• Use of prebiotics, or probiotics ≤2 weeks prior to the on-site study visit.
• Dementia in medical history.
• Insulin-dependent diabetes mellitus.
• Current Psychosis episode by clinical judgement based on anamnesis.
• Pregnancy.
• Alcohol or drug abuse.
• Deep brain stimulation or Duodopa/Lecigon treatment.