Rehabilitation of Rehabilitation of Finger Extension in Finger Extension in

Chronic Chronic HemiplegiaHemiplegia

Derek KamperDerek Kamper1,21,2 Tiffany KlineTiffany Kline44 Xun LuoXun Luo3 3

Robert KenyonRobert Kenyon1,31,3 Heidi WaldingerHeidi Waldinger1 1 Erik CruzErik Cruz11

William Z. RymerWilliam Z. Rymer1,21,2

11Sensory Motor Performance ProgramSensory Motor Performance Program22Northwestern UniversityNorthwestern University

33University of Illinois at ChicagoUniversity of Illinois at Chicago44Marquette UniversityMarquette University

BackgroundBackground

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

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

BackgroundBackgroundPreferential extensor weakness

24 stroke subjects, 6 control subjects

BackgroundBackgroundFlexor hypertonicity

Attempted voluntary isometric extensionAttempted voluntary isometric flexion

RationaleRationale

Evidence that sustained voluntary contractions can Evidence that sustained voluntary contractions can increase excitability of involved corticospinal pathways increase excitability of involved corticospinal pathways (Sacco et al., 1997)(Sacco et al., 1997)

Repetitive practice seems to lead to improvement, as Repetitive practice seems to lead to improvement, as shown with constraint-induced therapy (Page et al., shown with constraint-induced therapy (Page et al., 2004)2004) However, CTI may not be viable for subjects with However, CTI may not be viable for subjects with

severe impairment (Bonifer and Anderson, 2003)severe impairment (Bonifer and Anderson, 2003)

Aim: Develop device to Aim: Develop device to assist finger extension for assist finger extension for

rehabilitation therapy rehabilitation therapy

Assist extension onlyAssist extension only Externally actuatedExternally actuated LightweightLightweight SafeSafe Provide feedback of assistanceProvide feedback of assistance

Criteria

Current technologiesCurrent technologies

Functional Tone Management System

Hand Mentor, Kinetic Muscles, Inc.

Hand Master, Rutgers University

Development activitiesDevelopment activities

Body-powered orthosis (HandAid)

• Cable-driven• Biscapular abduction/

shoulder flexion produce finger extension

• Figure 8 harness• Force transducer

measures assistance

Development activitiesDevelopment activities

Development activitiesDevelopment activities

Pneumatically-powered hand (PneuHand)

ControlControl

Create desired trajectory from Create desired trajectory from object sizeobject size

Servo about desired trajectoryServo about desired trajectory Electro-pneumatic valveElectro-pneumatic valve

Provide assistance only when Provide assistance only when extensor EMG above threshold valueextensor EMG above threshold value

Subject populationSubject population

Chronic hemiplegia following stroke (> 9 months)Chronic hemiplegia following stroke (> 9 months) Stage 2 or 3 for hand on Chedoke-McMaster scale (< Stage 2 or 3 for hand on Chedoke-McMaster scale (<

50% full finger extension)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

Training paradigmTraining paradigm

3 groups3 groups HandAid, PneuHand, No assistanceHandAid, PneuHand, No assistance

Attempt to grasp virtual targets (30 min) and actual Attempt to grasp virtual targets (30 min) and actual objects (30 min)objects (30 min)

24 training sessions24 training sessions 3 sessions/week3 sessions/week 8 weeks total8 weeks total

Tests pre- and post-trainingTests pre- and post-training Kinetics (servomotor)Kinetics (servomotor) Kinematics (CyberGlove)Kinematics (CyberGlove) Function (Wolf Motor Function Test)Function (Wolf Motor Function Test)

Augmented reality Augmented reality

Glasstron head-mounted Glasstron head-mounted displaydisplay CAVElibraryCAVElibrary

Menu-driven object selectionMenu-driven object selection Object moves and rotates with Object moves and rotates with

hand once acquiredhand once acquired Flock of birds sensors on head Flock of birds sensors on head

and handand hand

Training

Augmented reality Augmented reality environmentenvironment