Could a common heart pill delay Parkinson's? small study hints at possibility

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Male or female of age between 50 and 85 years at time of enrollment. Diagnosis of idiopathic REM sleep behavior disorder (iRBD) or Diagnosis of hyposmia. Diagnosis of RBD will be, established either as 'definite RBD' according to the criteria proposed by the International Classification of Sleep Disorders (ICSD)-2 \[AASM, 2005\] or 'probable RBD' following a score of 6 or higher in the RBD questionnaire (RBDSQ) with a score of at least 1 in subitems 6.1 to 6.4 of question 6. At least one of the following: 1. Diagnosis of hyposmia. Diagnosis of hyposmia will be established as a University of Pennsylvania Smell Identification Test (UPSIT) score \< 20th percentile for the individual's age group and sex. 2. Functional constipation, assessed by a scores \> 4 on a questionnaire based on modified ROME III diagnostic criteria. 3. Color vision abnormality, as assessed using HRR Pseudoisochromatic Plates, in the absence of congenital dyschromatopsia. 4. Symptoms of depression, as assessed by a Beck Depression Inventory (BDI) fast screen score \>3 or concurrent use of antidepressant medications * Abnormal 123I-MIBG myocardial scintigraphy, as defined by a Late H/M ratio \< 2.2 and/or a WR \>30%, with normal cardiac ejection fraction (LVEF \>55%). * Capacity to give informed consent Exclusion Criteria: Secondary Parkinsonism, including tardive Concurrent dementia defined by a score lower than 22 on the MoCA Concurrent severe depression defined by a BDI fast screen score greater than 13 Comorbidities related to SNS hyperactivity Heart failure (LVEF \<45%) Recent myocardial revascularization (\<12 weeks) Chronic Hypertension (SBP\>140mmHg-DBP\>90mmHg) Atrial fibrillation Diabetes mellitus COPD Sleep Apnea Severely reduced kidney function (Glomerular Filtration Rate\<30ml/min) Contraindications to the use of carvedilol Asthma or bronchospasm Recent myocardial infarction (\<48 h) Ongoing unstable angina Cardiogenic shock or prolonged hypotension Second or Third-Degree AV block Significant valvular aortic stenosis Obstructive cardiomyopathy, or constrictive pericarditis Symptomatic Bradycardia (HR\<60) or Sick Sinus Syndrome Stroke within the past 1 month Severe Hepatic Dysfunction Allergy/hypersensitivity to iodine or study medication