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

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

Rationale Isometric extensor weakness 11 stroke subjects, 5 control subjects

Rationale Yet, extensor activity is present Attempted voluntary isometric extension Attempted voluntary isometric flexion

Rationale Suggestion that treatment can alter cortical and peripheral activation Constraint-induced use (Liepert et al., 1998; 2000) Voluntary wrist extension in CP subject prior to NMES therapy Voluntary wrist extension in CP subject after NMES therapy

Aim: Develop rehabilitation devices for hand Criteria Assist extension only Externally actuated Lightweight Safe Provide feedback of assistance Adaptable to assist individuated finger movements

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

Design of development activities Body-powered orthosis Cable-driven Biscapular abduction/ shoulder flexion produce finger extension Figure 8 harness Force transducer measures assistance

Design of development activities Current glove design Zipper across palm for ease of donning Cable housing sewn into dorsal side

Design of development activities Challenges Translation of cable housing Stiffness of PIP joint leads to hyperextension of DIP and MCP Cumbersome forearm cuff

Design of development activities Pneumatically-powered hand

Design of development activities Training Thrice weekly for 8 weeks Virtual targets Feedback of assistance level Glasstron head-mounted display CAVElibrary Use see-through VR to visualize object and hand GUI for therapist: select object type and size

Design of development activities Efficacy testing Free movement (CyberGlove®)

Design of development activities Efficacy testing Isometric and isokinetic (servomotor)