“…As its name implies, machine learning allows for a computer program to learn and extract meaningful representation from data in a semi-automatic manner. For the diagnosis of PD, machine learning models have been applied to a multitude of data modalities, including handwritten patterns (Drotár et al, 2015 ; Pereira et al, 2018 ), movement (Yang et al, 2009 ; Wahid et al, 2015 ; Pham and Yan, 2018 ), neuroimaging (Cherubini et al, 2014a ; Choi et al, 2017 ; Segovia et al, 2019 ), voice (Sakar et al, 2013 ; Ma et al, 2014 ), cerebrospinal fluid (CSF) (Lewitt et al, 2013 ; Maass et al, 2020 ), cardiac scintigraphy (Nuvoli et al, 2019 ), serum (Váradi et al, 2019 ), and optical coherence tomography (OCT) (Nunes et al, 2019 ). Machine learning also allows for combining different modalities, such as magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) data (Cherubini et al, 2014b ; Wang et al, 2017 ), in the diagnosis of PD.…”