1. Rehabilitation of Finger Extension in Chronic Hemiplegia
Derek Kamper1,2 Tiffany Kline4 Xun Luo3
Robert Kenyon1,3 Heidi Waldinger1 Erik Cruz1
William Z. Rymer1,2
1Sensory Motor Performance Program
2Northwestern University
3University of Illinois at Chicago
4Marquette University

2. Background
Friedland, F., “Physical Therapy,” in Stroke and its Rehabilitation
Limited finger extension is the most common chronic motor impairment following stroke (Trombly, 1989).

3. Background Preferential extensor weakness
24 stroke subjects, 6 control subjects

4. Background Flexor hypertonicity
Attempted voluntary isometric extension
Attempted voluntary isometric flexion

5. Rationale
Evidence that sustained voluntary contractions can increase excitability of involved corticospinal pathways (Sacco et al., 1997)
Repetitive practice seems to lead to improvement, as shown with constraint-induced therapy (Page et al., 2004)
However, CTI may not be viable for subjects with severe impairment (Bonifer and Anderson, 2003)

6. Aim: Develop device to assist finger extension for rehabilitation therapy
Criteria
Assist extension only
Externally actuated
Lightweight
Safe
Provide feedback of assistance

7. Current technologies Hand Master, Rutgers University
Functional Tone Management System
Hand Mentor, Kinetic Muscles, Inc.

8. Development activities
Body-powered orthosis (HandAid)
Cable-driven
Biscapular abduction/ shoulder flexion produce finger extension
Figure 8 harness
Force transducer measures assistance

9. Development activities

10. Development activities
Pneumatically-powered hand (PneuHand)

11. Control Create desired trajectory from object size
Servo about desired trajectory
Electro-pneumatic valve
Provide assistance only when extensor EMG above threshold value

12. Subject population Chronic hemiplegia following stroke (> 9 months)
Stage 2 or 3 for hand on Chedoke-McMaster scale (< 50% full finger extension)
Absence of visuoperceptual disturbance
Absence of fixed contracture
Capacity to provide informed consent

13. Training paradigm 3 groups
HandAid, PneuHand, No assistance
Attempt to grasp virtual targets (30 min) and actual objects (30 min)
24 training sessions
3 sessions/week
8 weeks total
Tests pre- and post-training
Kinetics (servomotor)
Kinematics (CyberGlove)
Function (Wolf Motor Function Test)

14. Augmented reality Training Glasstron head-mounted display
CAVElibrary
Menu-driven object selection
Object moves and rotates with hand once acquired
Flock of birds sensors on head and hand

15. Augmented reality environment