PD sign | KINARM Task | Task parameter | Subject performance compared to controls (statistical test) | ROC AUC (95% confidence interval) | Performance correlateda to UPDRS subscoreb |
---|---|---|---|---|---|
Bradykinesia | Object hit task | Mean hand speed | 41% slower (MW, U = 365, P < 0.001) | 0.94 (0.90–0.98) | c.c. = − 0.615, P < 0.001 |
Movement area | 31% smaller (Student t-test, t = 6.7, P < 0.001) | 0.84 (0.76–0.92) | c.c. = − 0.411, P < 0.05 | ||
Total hits | 25% less targets (MW, U = 642, P < 0.001) | 0.90 (0.85–0.95) | n.s. (P = 0.27) | ||
Object hit and avoid task | Mean hand speed | 47% slower (Student t-test, t = 9.6, < 0.001) | 0.93 (0.87–0.98) | c.c. = − 0.633, P < 0.001 | |
Movement area | 40% smaller (Student t-test, t = 8.9, < 0.001) | 0.91 (0.85–0.97) | c.c. = − 0.594, P < 0.01 | ||
Total hits | 23% less targets (Student t-test, t = 8.7, < 0.001) | 0.88 (0.81–0.96) | n.s. (P = 0.055) | ||
Distractor hits | n.s. (MW, U = 1962, P = 0.276) | n.s. (0.45–0.69) | n.s. (P = 0.102) | ||
Rigidity | Passive stretch task | Start total torques | n.s. (Student t-test, t = − 1.696, P = 0.096) | n.s. (0.48–0.80) | n.s. P = 0.09) |
End total torques | 34% lower (Student t-test, t = − 6.245, < 0.001) | 0.91 (0.82–0.99) | c.c. = − 0.464, P < 0.05 | ||
Total torque difference | 64% higher (Student t-test, t = −4.844, P < 0.001) | 0.81 (0.69–0.94) | n.s. (P = 0.45) | ||
Hold torque | 3.6 times greater (MW, U = 219, P < 0.05) | 0.68 (0.52–0.83) | n.s. (P = 0.20) | ||
Peak speeds | 9% slower (MW, U = 118, P < 0.001) | 0.83 (0.71–0.94) | n.s. (P = 0.25) | ||
Postural stability | Unloading task | Deceleration time (ms) | 9% faster (Student t-test, t = − 2.305, P < 0.05) | 0.66 (0.53–.80) | n.s. (P = 0.42) |
Maximum displacement | 29% shorter (MW, U = 277, P < 0.01) | 0.71 (0.57–0.85) | n.s. (P = 0.69) | ||
Return time | n.s. (MW, U = 452, P = 0.75) | n.s. (0.37–0.68) | n.s. (P = 0.35) | ||
Endpoint error | n.s. (MW, U = 447, P = 0.70) | n.s. (0.38–0.68) | n.s. (P = 0.23) |