Fig. 1: Machine learning workflow for developing and validating an abbreviated smell test for Parkinson’s disease.

Details of the workflow are as indicated and described in Methods and Result sections of the main text. SST-ID Sniffin’ Sticks Identification test, UPSIT University of Pennsylvania Smell Identification Test, DeNoPa De Novo Parkinson Study, PROBE Prognostic Biomarkers in Parkinson Disease, HC healthy control, PD Parkinson disease, DLB dementia with Lewy bodies, MSA multiple system atrophy, PSP progressive supranuclear palsy, ROC receiver operating characteristic, AUC area under the ROC curve.