Demographic, clinical and global imaging details of each group
| Controls | PD-N | PD-MCI | PD-D | |
| n | 34 | 57 | 23 | 16 |
| Age (years)* | 69.6 (9.2) | 64.3 (8.7) | 70.8 (8.0) | 73.3 (7.0) |
| Sex (male:female) | 23:11 | 39:18 | 14:9 | 14:2 |
| MMSE* | 28.9 (1.0) | 29.0 (1.2) | 27.7 (1.5) | 23.9 (3.1) |
| MoCA* | 27.0 (2.0) | 26.7 (2.3) | 22.6 (2.3) | 16.3 (3.9) |
| Cognitive z score* | 0.62 (0.38) | 0.31 (0.39) | −0.70 (0.41) | −1.74 (0.56) |
| GDS* | 0 (0–1) | 0 (0–9) | 0 (0–11) | 4.5 (0–8) |
| NPI* | – | 0 (0–22) | 4 (0–20) | 6 (0–28) |
| Reisberg Global Deterioration Scale* | – | 1 (1–2) | 2 (1–3) | 4 (3–6) |
| UPDRS-III* | – | 25.9 (14.2) | 35.7 (18.7) | 48.9 (15.7) |
| Disease duration (years)* | – | 3.8 (3.3) | 7.2 (5.0) | 12.9 (8.8) |
| Hoehn and Yahr* | – | 2 (1–3) | 2.5 (1.5–4) | 4 (2–4) |
| LED (mg/day)* | – | 203 (297) | 400 (359) | 703 (378) |
| ICV (cm3) | 1510 (173) | 1551 (165) | 1501 (102) | 1624 (178) |
| Global GM vol/ICV* | 0.44 (0.036) | 0.44 (0.03) | 0.42 (0.02) | 0.40 (0.02) |
Values are mean (SD), except median (range) for GDS, Global Deterioration Scale, Hoehn and Yahr stage and NPI.
Global Deterioration Scale and NPI scores were available for a subset of PD patients (PD-N, n=24; PD-MCI, n=17; PD-D, n=16).
Significant ANOVA/Kruskal-Wallis across groups, *p<0.002.
GDS, Geriatric Depression Scale-short form; GM, grey matter, ICV, intracranial volume; LED, levodopa equivalent dose; MMSE, Mini-Mental State Examination; MoCA, Montreal cognitive assessment; NPI, Neuropsychiatric Inventory; PD-D, Parkinson's disease with dementia; PD-MCI, Parkinson's disease with mild cognitive impairment; PD-N, Parkinson's disease with normal cognition; UPDRS-III, Unified Parkinson's Disease Rating Scale part III.