Skip to main content

Table 2 Comparison of PD subjects KINARM task OFF DRT performance to (1) healthy controls and (2) UPDRS ratings

From: Integrated robotics platform with haptic control differentiates subjects with Parkinson’s disease from controls and quantifies the motor effects of levodopa

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)

  1. aSpearman Rank Order Correlation, n.s. not significant, MW Mann-Whitney Rank Sum Test, c.c. Spearman Rank Order Correlation, bUPDRS subscore for bradykinesia score used items 23–26 (maximum score = 32), UPDRS subscore for rigidity score used item 22 (maximum score = 20), and UPDRS subscore for posture stability score used item 30 (maximum score = 4)