Objective: To follow-up prodromal Parkinson’s Disease (PD) subtypes in a longitudinal cohort study, validating new biomarkers and ethical guidelines for early detection of PD.

Background: In the last years several high-risk cohort studies for individuals with an increased likelihood of developing PD have been initiated. However, the hypothesis of a “brain-first” vs. “body-first” disease progression¹ has not been followed in prodromal cohort studies, yet. Moreover, previous studies lack a standardized ethical support for individuals participating in a study screening for prodromal PD.

Method: The PASS-PD (Prodromal α-Synuclein Screening Study in PD) Study was designed as a 5-year observational cohort study, following and comparing the progression of clinical, digital and blood based biomarkers of two proposed prodromal subtypes of PD: a) The REM sleep behavior disorder (RBD) positive (“body-first”) subgroup, including individuals with idiopathic polysomnographic proven RBD (n=40) and b) the RBD negative (“brain-first”) subgroup, including individuals with a likelihood ratio of >50% for being in the prodromal phase of PD following the MDS Criteria² (n=60)._. Individuals for the RBD negative group are recruited from the general population using a short questionnaire in asking for at least two of four core markers (depression, constipation, hyposmia, positive family history), followed by an assessment of MDS criteria for prodromal PD. All assessments and recruitment efforts follow standardized ethical protocols taking into account each individual’s right not to know, regular support offers and advice on lifestyle adjustments³. Follow-up assessments focus on non-motor symptom progression, digital biomarkers and new techniques for α-synuclein detection in blood and cerebral spinal fluid.

Results: So far ten individuals for the “body-first” subgroup have been recruited and underwent all baseline assessments. Following the pre-screening of 80 individuals from the general population, ten individuals qualified for further screening for the “brain-first” subgroup. Anonymous evaluation surveys revealed that efforts for standardized ethical support of the study are very well accepted.

Conclusion: The PASS-PD study follows for the first time potential subtypes of prodromal PD in an observational cohort study, implementing new guidelines for ethical handling with high-risk individuals.

References: 1 Horsager J et al. Brain-first versus body-first Parkinson’s disease: a multimodal imaging case-control study. Brain. 2020 Oct 1;143(10):3077-3088.
2 Heinzel S et al. MDS Task Force on the Definition of Parkinson’s Disease. Update of the MDS research criteria for prodromal Parkinson’s disease. Mov Disord. 2019 Oct;34(10):1464-1470. doi: 10.1002/mds.27802. Epub 2019 Aug 14. PMID: 31412427.
3 Schaeffer E et al. Risk Disclosure in Prodromal Parkinson’s Disease. Mov Disord. 2021 Dec;36(12):2833-2839.

« Back to 2022 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/design-of-a-prodromal-screening-study-for-subtypes-in-parkinsons-disease/