Rehabilitation of Finger Rehabilitation of Finger Extension in Chronic Extension in Chronic

HemiplegiaHemiplegiaDerek G. KamperDerek G. Kamper1,21,2

Robert V. KenyonRobert V. Kenyon1,31,3

William Z. RymerWilliam Z. Rymer1,21,2

Erik CruzErik Cruz11

Xun LuoXun Luo33

Heidi WaldingerHeidi Waldinger11

1Sensory Motor Performance Program1Sensory Motor Performance Program2Northwestern University2Northwestern University3University of Illinois at Chicago3University of Illinois at Chicago

MotivationMotivation

Limited finger extension is the most common chronic motor impairment following stroke (Trombly, 1989).

Friedland, F., “Physical Therapy,” in Stroke and its Rehabilitation

RationaleRationaleIsometric extensor weakness

11 stroke subjects, 5 control subjects

RationaleRationaleYet, extensor activity is present

Attempted voluntary isometric extensionAttempted voluntary isometric flexion

RationaleRationaleSuggestion that treatment can alter cortical and peripheral activation

Voluntary wrist extension in CP subject prior to NMES therapy

Voluntary wrist extension in CP subject after NMES therapy

Constraint-induced use (Liepert et al., 1998; 2000)

Aim: Develop rehabilitation Aim: Develop rehabilitation devices devices for handfor hand

• Assist extension onlyAssist extension only

• Externally actuatedExternally actuated

• LightweightLightweight

• SafeSafe

• Provide feedback of assistanceProvide feedback of assistance

• Adaptable to assist individuated Adaptable to assist individuated finger movementsfinger movements

Criteria

Subject populationSubject population

• Chronic hemiplegia following stroke (> 9 Chronic hemiplegia following stroke (> 9 months)months)

• Stage 2 or 3 for hand on Chedoke-McMaster Stage 2 or 3 for hand on Chedoke-McMaster scale (< 50% full finger extension)scale (< 50% full finger extension)

• Absence of visuoperceptual disturbanceAbsence of visuoperceptual disturbance• Absence of fixed contractureAbsence of fixed contracture• Capacity to provide informed consentCapacity to provide informed consent

Design of development Design of development activitiesactivitiesBody-powered orthosis

• Cable-driven• Biscapular abduction/

shoulder flexion produce finger extension

• Figure 8 harness• Force transducer

measures assistance

Design of development Design of development activitiesactivitiesCurrent glove design

Zipper across palm for ease of donning Cable housing sewn into dorsal side

Design of development Design of development activitiesactivitiesChallenges

• Translation of cable housing• Stiffness of PIP joint

• leads to hyperextension of DIP and MCP• Cumbersome forearm cuff

Design of development Design of development activitiesactivitiesPneumatically-powered hand

Design of development Design of development activitiesactivities

• Thrice weekly for 8 Thrice weekly for 8 weeksweeks

• Virtual targetsVirtual targets

• Feedback of Feedback of assistance levelassistance level

Training

• 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 Design of development activitiesactivities

Efficacy testing

Free movement (CyberGlove®)

Design of development Design of development activitiesactivities

Motor Shaft

Air Bladder

Channel

VacuumPump Tube

Efficacy testing

Isometric and isokinetic (servomotor)