“…Previous studies investigating the impact of MRI measures on cognitive and motor symptoms in PD have mostly been cross sectional in their WMH and GM assessments ( Zeighami et al, 2015 , Dadar et al, 2018a , de Schipper et al, 2019 , Toda et al, 2019 , Stojkovic et al, 2018 , Dadar, et al, 2020 , Zeighami et al, 2017 , Fang et al, 2020 , Wan et al, 2019 ), are mainly from the Parkinson's Progression Markers Initiative (PPMI) study which includes only de novo PD patients at baseline ( Zeighami et al, 2015 , Zeighami et al, 2019 , Dadar et al, 2018a , Dadar, et al, 2020 , Zeighami et al, 2017 , Chahine et al, 2019 ), and most don’t assess the impact of grey matter and white matter measures in the same setting ( Zeighami et al, 2015 , Zeighami et al, 2019 , de Schipper et al, 2019 , Pozorski et al, 2019 , Toda et al, 2019 , Stojkovic et al, 2018 , Dadar, et al, 2020 , Zeighami et al, 2017 , Wan et al, 2019 , Chahine et al, 2019 ). In comparison, there are several strengths to the present study.…”