Bayesian network modeling of risk and prodromal markers of Parkinson’s disease
PLOS ONE
RESEARCH ARTICLE
Bayesian network modeling of risk and
prodromal markers of Parkinson’s disease
Meemansa Sood ID1,2, Ulrike Suenkel3, Anna-Katharina von Thaler4, Helena
U. Zacharias5,6, Kathrin Brockmann4,7, Gerhard W. Eschweiler3,8, Walter Maetzler9,
Daniela Berg4,9, Holger Fröhlich ID1,2☯*, Sebastian Heinzel ID9,10☯*
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1 Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing (SCAI), Sankt
Augustin, Germany, 2 Bonn-Aachen International Center for IT, University of Bonn, Bonn, Germany,
3 Department of Psychiatry and Psychotherapy, Tübingen University Hospital, Tübingen, Germany,
4 Department of Neurodegeneration, Hertie Institute for Clinical Brain Research, University of Tübingen,
Tübingen, Germany, 5 Department of Internal Medicine I, University Medical Center Schleswig-Holstein,
Campus Kiel, Kiel, Germany, 6 Institute of Clinical Molecular Biology, Kiel University and University Medical
Center Schleswig-Holstein, Campus Kiel, Kiel, Germany, 7 German Center for Neurodegenerative Diseases,
University of Tübingen, Tübingen, Germany, 8 Geriatric Center, Tübingen University Hospital, Tübingen,
Germany, 9 Department of Neurology, Christian-Albrechts University, Kiel, Germany, 10 Institute of Medical
Informatics and Statistics, Kiel University, University Hospital Schleswig-Holstein, Kiel, Germany
☯ These authors contributed equally to this work.
* (SH); (HF)
OPEN ACCESS
Citation: Sood M, Suenkel U, von Thaler A-K,
Zacharias HU, Brockmann K, Eschweiler GW, et al.
(2023) Bayesian network modeling of risk and
prodromal markers of Parkinson’s disease. PLoS
ONE 18(2): e0280609. https://doi.org/10.1371/
journal.pone.0280609
Editor: Tommaso Martino, Policlinico Riuniti of
Foggia: Neuroscience Department, S.C.
Ospedaliera of Neurology-Stroke Unit, ITALY
Received: October 10, 2022
Accepted: January 3, 2023
Published: February 24, 2023
Copyright: © 2023 Sood et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: Given that this study
uses a compehensive body of prospective TREND
cohort data and to prevent misuse, the longitudinal
data of >1200 participants cannot be shared
publicly. Data will be shared (upon request) with
researchers and for research purposes only. For
data requests, please contact the Organizational
team and Steering committee of the TREND study
via: info(at)trend-studie.de.
Abstract
Parkinson’s disease (PD) is characterized by a long prodromal phase with a multitude of
markers indicating an increased PD risk prior to clinical diagnosis based on motor symptoms. Current PD prediction models do not consider interdependencies of single predictors, lack differentiation by subtypes of prodromal PD, and may be limited and potentially
biased by confounding factors, unspecific assessment methods and restricted access to
comprehensive marker data of prospective cohorts. We used prospective data of 18
established risk and prodromal markers of PD in 1178 healthy, PD-free individuals and 24
incident PD cases collected longitudinally in the Tübingen evaluation of Risk factors for
Early detection of NeuroDegeneration (TREND) study at 4 visits over up to 10 years. We
employed artificial intelligence (AI) to learn and quantify PD marker interdependencies via
a Bayesian network (BN) with probabilistic confidence estimation using bootstrapping.
The BN was employed to generate a synthetic cohort and individual marker profiles.
Robust interdependencies were observed for BN edges from age to subthreshold parkinsonism and urinary dysfunction, sex to substantia nigra hyperechogenicity, depression,
non-smoking and to constipation; depression to symptomatic hypotension and excessive
daytime somnolence; solvent exposure to cognitive deficits and to physical inactivity; and
non-smoking to physical inactivity. Conversion to PD was interdependent with prior subthreshold parkinsonism, sex and substantia nigra hyperechogenicity. Several additional
interdependencies with lower probabilistic confidence were identified. Synthetic subjects
generated via the BN based representation of the TREND study were realistic as
assessed through multiple comparison approaches of real and synthetic data. Altogether
our work demonstrates the potential of modern AI approaches (specifically BNs) both for
modelling and understanding interdependencies between PD risk and prodromal markers,
PLOS ONE | https://doi.org/10.1371/journal.pone.0280609 February 24, 2023
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PLOS ONE
Funding: The TREND study is being conducted at
the University Hospital Tübingen and has been
supported by the Hertie Institute for Clinical Brain
Research, the DZNE, the Geriatric Center of
Tübingen, the Center for Integrative Neuroscience,
Teva Pharmaceutical Industries, Union Chimique
Belge, Janssen Pharmaceuticals, the International
Parkinson Foundation and the German Research
Society (DFG). This work was (partially) funded by
DIGIPD (01KU2110), a project supported by the
Federal Ministry of Science and Education (BMBF),
under the frame of ERA PerMed. HUZ is supported
by the Federal Ministry of Education and Research
(Bundesministerium für Bildung und Forschung;
BMBF) within the framework of the e:Med research
and funding concept (grant 01ZX1912A). The
funders had no role in study design, data collection
and analysis, decision to publish, or preparation of
the manuscript. There was no additional external
funding received for this study. There was no
additional external funding received for this study.
Competing interests: The authors have declared
that no competing interests exist.
Network of prodromal Parkinson markers
which are so far not accounted for in PD prediction models, as well as for generating realistic synthetic data.
Introduction
Parkinson’s disease (PD) is characterized by progressive neurodegeneration that has usually
advanced for many years before it is clinically diagnosed [1]. In addition to old age, a multitude
of risk markers, such as genetic factors, lifestyle, environmental factors, (comorbid) diseases
(e.g., diabetes) as well as biomarkers (e.g., low plasma urate levels, hyperechogenicity of the
substantia nigra) have been shown to indicate an increased risk of PD in prospective studies
[2, 3]. Moreover, prodromal markers like depression, autonomous dysfunction, REM-sleep
behavior disorder (RBD), subtle motor signs and pathological dopaminergic imaging [3–5]
may already indicate early neurodegenerative processes that can ultimately lead to the clinical
diagnosis of PD. The International Parkinson and Movement Disorder Society (MDS)
research criteria for prodromal PD [3, 6] have been designed to review and continually update
the predictive values of risk and prodromal markers (...truncated)