Table 1.
Demographic and clinical characteristics of patients with PD and ET in comparison with healthy individuals (HC)
| Variable group | Variable | PD | ET | HC | P valuea |
|---|---|---|---|---|---|
| Demographics | n | 146 | 42 | 38 | – |
| Age, years | 66.0 (15) | 66.0 (17.0) | 68.0 (14.0) | 0.420 | |
| Sex, male/female | 73/73 | 20/22 | 19/19 | 0.962 | |
| Handedness, right/left/symmetrical | 135/7/4 | 36/3/3 | 35/2/1 | 0.663 | |
| Levodopa-treated, yes/no | 28/118 | 1/41 | 0/38 | < 0.001 | |
| LEDD, mg | 381 (158)b,c | 200 (0) | – | < 0.001 | |
| Motor symptoms | MDS-UPDRS III motor score | 34.0 (21.5)c | 33.5 (20.3)c | 5.5 (7.3) | < 0.001 |
| MDS UPDRS III bradykinesia subscore | 18.5 (13.0)c | 15.0 (11.0)c | 4.0 (6.0) | < 0.001 | |
| Predominant side of motor symptoms, right/left/symmetrical | 24/36/86 | 5/1/36 | – | 0.002 | |
| Motor symptom duration, months | 18.0 (25.0) | 27.0 (96.0) | – | < 0.001 | |
| Cognition | MMSE | 28.0 (3.0) | 28.0 (3.0) | 28.0 (2.0) | 0.160 |
| Depression | BDI | 6.0 (7.0) | 6.8 (9.1) | 1.0 (6.0) | < 0.001 |
| Micrographia | Consistent, mean height of letters, mm | 4.3 (1.9)b,c | 5.0 (1.7) | 5.0 (1.4) | < 0.001 |
| Consistent, mean area of writing sample, mm2 | 399 (301)b,c | 536 (397) | 548 (286) | < 0.001 | |
| Progressive, b value | − 0.14 (0.26)b | − 0.06 (0.18) | − 0.06 (0.32) | 0.014 | |
| Drawing, cm2 | 22.8 (25.4) | 26.7 (22.6) | 25.8 (28.0) | 0.485 | |
| DAT SBR | Caudate nucleus | 2.08 (0.78)b,c | 3.09 (1.23)c | 2.58 (0.54) | < 0.001 |
| Anterior putamen | 1.56 (0.78)b,c | 2.96 (1.07) | 2.50 (0.60) | < 0.001 | |
| Posterior putamen | 0.90 (0.56)b,c | 2.53 (0.87) | 2.18 (0.59) | < 0.001 | |
| Right posterior putamen | 0.93 (0.61)b,c | 2.60 (1.00) | 2.22 (0.55) | < 0.001 | |
| Left posterior putamen | 0.89 (0.54) b,c | 2.58 (0.90) | 2.17 (0.51) | < 0.001 |
Values are medians (IQR). One patient with ET was treated with levodopa at the time of imaging, before the diagnosis was confirmed
aKruskal-Wallis test, Pearson Chi-square test or Fisher’s exact test as appropriate
b,c,dSignificantly different compared to ET (b) or HC (c) in pairwise comparison with Kruskal–Wallis test adjusted by the Dunn-Bonferroni’s correction for multiple test
PD Parkinson’s disease, ET essential tremor, HC Healthy control, MMSE Mini Mental State Examination, BDI Beck’s Depression Inventory