Figure 1.

Comparison of local gyrification index between Parkinson disease (PD) subgroups and controls (left) and among PD subgroups (right) at baseline. In this study, PD patients were grouped based on the number of years since diagnosis into PD‐early (PE_E; < 1 year, baseline UPDRS‐III on medication of 11.4 ± 8.2, baseline Hoehn and Yahr stage 1.4 ± 0.6), PD‐middle (PE_M; 1‐5 years, baseline UPDRS‐III on medication of 19.8 ± 10.4, baseline Hoehn and Yahr stage 1.4 ± 0.6), and PD‐late (PE_L; > 5 years, baseline UPDRS‐III on medication of 20.4 ± 11.9, baseline Hoehn and Yahr stage 2.2 ± 0.6). PD with a long disease duration had reduced gyrification bilaterally in several cortical areas including M1 compared to controls at baseline (left). These patients also had reduced gyrification in several neocortical areas when compared with PD with short and medium disease duration at baseline (right). Figure reprinted with permission from Sterling NW, Wang M, Zhang L, et al. Stage‐dependent loss of cortical gyrification as Parkinson disease “unfolds”. Neurology 2016;86(12):1143‐1151.109