Objective: To compare remote application of the Movement Disorder Society (MDS) prodromal Parkinson’s disease (PD) criteria to expert clinical determination of possible parkinsonism in a cohort of LRRK2 G2019S carriers without self-reported PD.

Background: Prior work has shown that the MDS prodromal PD criteria have high sensitivity and specificity for detecting prodromal PD among LRRK2 carriers assessed in-person [1]. However, the validity of remote application of these criteria has not been assessed.

Method: Using the MDS prodromal PD criteria [2], we calculated likelihood ratios and estimated the probability of prodromal PD among LRRK2 carriers ≥ 50 years of age without PD enrolled in a 36-month decentralized study. We considered those with ≥ 80% probability to meet criteria for prodromal PD.  Participants completed standard questionnaires assessing motor, psychiatric, autonomic, and sleep domains, and the University of Pennsylvania Smell Identification Test. Participants also provided information on family history of PD, environmental risk factors (caffeine use, smoking history, pesticide and occupational solvent exposure), and relevant diagnostic testing. A movement disorders expert blinded to self-reported PD status conducted a modified Movement Disorder Society –   Unified Parkinson Disease Rating Scale (MDS-UPDRS) motor examination and provided their determination on possible parkinsonism.

Results: At baseline, non-manifest participants (n=218 with mean (SD) age 54.8 (15.2) and 59% female) had mean (SD) modified MDS-UPDRS motor score 1.8 (4.5), Scales for Outcomes in PD-Autonomic score 7.5 (5.9), and Beck Depression Inventory-II score 4.3 (5.8). In addition, 24% (47/200) had hyposmia according to age-based cut-offs and 25% (54/215) screened positive for REM sleep behavior disorder. The prodromal PD criteria was not applied in 91 participants–84 were too young and 7 had expert-assessed PD. Twelve (9% of 127) participants met criteria for prodromal PD. Experts identified possible parkinsonism in 18 participants; in six cases, participants also met criteria for prodromal PD.

Conclusion: In a cohort of LRRK2 G2019S carriers at increased risk for PD, remote application of the MDS prodromal PD criteria was feasible. Expert assessment of motor function identified more cases of possible parkinsonism. Longitudinal follow-up of this cohort will establish the sensitivity and specificity of remote application of these criteria.

References: [1] Mirelman A, Saunders-Pullman R, Alcalay RN, et al. Application of the Movement Disorder Society prodromal criteria in healthy G2019S-LRRK2 carriers. Mov Disord. 2018;33(6):966-973. doi:10.1002/mds.27342 [2] Berg D, Postuma RB, Adler CH, et al. MDS research criteria for prodromal Parkinson’s disease. Mov Disord. 2015;30(12):1600-1611. doi:10.1002/mds.26431

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MDS Abstracts - https://www.mdsabstracts.org/abstract/remote-assessment-of-prodromal-parkinsons-disease-in-a-lrrk2-g2019s-cohort/