Demographic, clinical, and manometric variables in early and late stages of Parkinson's disease (PD)
| Early PD | Late PD | p Value | |
| Sex (M/F) | 7/4 | 12/8 | — |
| Age (y) | 65 (22–89) | 76.5 (60–88) | 0.052 |
| Constipation | 6/11 (54.5%) | 16/20 (80%) | NS |
| Straining | 3/11 (27.3%) | 11/20 (55%) | NS |
| IAS pressure (mm Hg) | 62 (15.5–91) | 49.7 (10–88) | NS |
| MRV (ml) | 30 (10–30) | 20 (0–40) | NS |
| DST (ml) | 100 (40–170) | 70 (10–600) | NS |
| dyssynergia | 7/11 (63.6%) | 12/20 (60%) | NS |
Abbreviations as in table 1.