Table 2.
Center of pressure (CoP) parameters for older adults with Parkinson’s disease and older adults without PD in bipedal and unipedal stances during firm and compliant surface conditions.
| Firm | CoP area (mm2) | Norm. area (mm2/s) | CoP velocity (mm/s) | CoP SD AP (mm) | CoP amplitude AP (mm) | CoP amplitude ML (mm) |
|---|---|---|---|---|---|---|
| Bipedal PD | 545.3 ± 467.0 | 9.1 ± 7.9 | 18.8 ± 14.9 | 5.5 ± 1.9 | 34.1 ± 12.6 | 26.0 ± 13.8 |
| Bipedal OA | 311.9 ± 202.1 | 5.2 ± 3.4 | 11.8 ± 4.5 | 5.4 ± 1.9 | 29.1 ± 8.2 | 17.3 ± 8.3 |
| Unipedal PD | 1578.7 ± 573.2* | 83.5 ± 92.5* | 58.9 ± 19.5* | 10.3 ± 2.5* | 55.5 ± 15.4* | 47.3 ± 27.8* |
| Unipedal OA | 1789.7 ± 880.9* | 41.8 ± 34.6* | 69.5 ± 26.1* | 10.9 ± 3.8* | 67.6 ± 25.9* | 44.1 ± 9.3* |
| Compliant | ||||||
| Bipedal PD | 540.8 ± 265.0 | 8.1 ± 4.3 | 22.7 ± 17.4 | 7.7 ± 3.0 | 40.6 ± 13.4 | 27.2 ± 8.8 |
| Bipedal OA | 437.4 ± 281.9 | 7.3 ± 4.7 | 13.9 ± 5.6 | 6.5 ± 2.2 | 35.4 ± 10.9 | 20.7 ± 7.8 |
| Unipedal PD | 1856.0 ± 829.2* | 51.2 ± 53.6* | 50.2 ± 17.1* | 11.7 ± 2.6* | 68.3 ± 17.7* | 51.8 ± 40.4* |
| Unipedal OA | 1575.0 ± 521.1* | 45.6 ± 34.2* | 65.0 ± 20.0* | 9.9 ± 2.0* | 81.6 ± 55.0* | 52.6 ± 19.5* |
BP, bipedal; UP, unipedal; PD, older adults with Parkinson’s disease; OA, older adults without PD; CoP, center of pressure; SD, standard deviation; Norm. area, time-normalized area. AP, anteroposterior; ML, Mediolateral; s, seconds. *Differs from bipedal stance for same surface condition.