1. AlterG Bionic Leg Dan Lewis, PT Deb Soares OTR/L
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2. Anti-Gravity Treadmill
AlterG Products
Anti-Gravity Treadmill
Bionic Leg
AlterG
AlterG now offers two unique high-tech mobility solutions for the rehab market. Both products facilitate greater amounts of rehab activities and the ability to progress patients to higher level activities than would otherwise be possible.
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DAN

3. Potential Influence of AlterG Technology
AlterG Bionic Leg & AlterG Anti-Gravity Treadmill
Motor and Sensory Input
Increased ROM, strength
Varied repetition at limit of performance. Feedback from successful performance
Neuroplasticity/ Motor Learning
Improved Performance
Reduce Support (BW %, Threshold, Assistance)
Burridge, Feb 2009.
Participation in greater massed practice, with feedback leads to strength gains.
Varying the practice conditions to keep the patient challenged near their current limit of performance leads to greater potential for motor learning.
Customizable settings allow the therapy to be progressed for continual challenge to the patient.
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DAN

4. AlterG Bionic Leg
The Bionic Leg translates patient intention into robotic assistance. It does this through weight sensors under the patient’s foot, along with motion sensors at the knee. The assistance is entirely customizable by the treating clinician.
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DAN

5. The Bionic Leg - What is it?
Robotic leg orthosis
Robotic assistance based on patient initiated movement
Two dynamic motors
High torque for up and down
High speed to enable swing phase
Foot sensors are miniature load cells that sense downward pressure to activate the leg
Programmable for appropriate level of assistance as patient progresses
Again, the key is active patient participation in initiating movement that is required to trigger the assistance from the device. The high-speed motor allows the device to move “out of the way” when assistance is NOT required. This allows for the maximum participation by the patient. This ability to “get out of the way” is referred to as “transparency” in robotic devices and is believed to help drive functional improvements by allowing for greater patient participation.
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DAN

6. Dynamic, “As Needed” Assistance
Weight shift triggers:
Assistance (stand)
Resistance (sit)
Stabilization (walk)
Weight shift and knee motion trigger assistance with knee extension and resistance to knee flexion. This, along with the physical support of the device act to stabilize the patient’s weak leg in all standing activities. The amount of assistance and resistance provided are highly customizable, based on the patient’s needs.
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DAN
Easily Programmable to Match Patient’s Functional Level

7. Leg Specs Leg weight approx. 8 lbs.
Minimum to maximum patient height 5’-6’6”
Minimum to maximum weight appx lbs.
Battery life-1-2 hours, requires only 45 min to charge
Foot sensors 4 sizes each side, total of 8 included
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DAN

8. Clinical Benefits: Confidence for Patients and Therapists
Allows patients to safely do more repetitions of higher level activities
Strengthens muscles and enables active motor learning
Allows therapist to focus on function-not lifting patient
Improves functional mobility with carry over
Pre Gait Activities - Improve stance stability, weight shift, balance
Safely supports patient, protects therapist
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DEB

9. Clinical Benefits Another “tool in the toolbox” for therapists
Allows low mobility patients to perform standing/functional activities
Something to integrate into existing therapy to be more effective
Provides stance stability
Gives patient and therapist a stable base to work from
Like an “extra set of hands for the therapist”
Allows the therapist to better facilitate quality of motion
Patients will usually have instability further up the chain from the knee. I initially hear this from therapists, but by stabilizing at the knee, we now have a stable base for the patient to work from, performing standing functional activities that can strengthen at the hip, pelvis and trunk.
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DEB

10. Maximizes Inputs Needed for Effective Therapy
Effective, Durable Therapy
Improves Confidence
Maximizes Repetitions
Increases Intensity, Engagement
Corrects Biomechanical Movement

11. First patients: (57 Year old, 8 Years s/p stroke)
Before - “Compensatory for Life”
After - “Independent Safety”
Today, 2 years post study: m/s
Ambulation (m/s)
Endurance (m)
Berg Balance
.05 23
Initial assessment
Show 1st and last 5 sec
.13 38 40
After 4 weeks, 2 sessions/week
.17 66 50
1 month after end of treatment

12. DIAGNOSES Difficulty with sit to stand Poor gait symmetry
IMPAIRMENTS
Lower extremity weakness
Decreased stance stability
Decreased standing tolerance
Ataxia
Asymmetrical weight-bearing
Decreased active knee extension
Decreased terminal knee extension control
Decreased proprioreception/sensation
Inattention/neglect
*Balance dysfunction
FUNCTIONAL DEFICITS
Difficulty with sit to stand
Poor gait symmetry
Flexed posture
Stairs
DIAGNOSES
CVA
TBI
Incomplete Spinal Cord Injury
Parkinson’s MS
Post-hip or knee replacement
When I train clinicians, I try to focus on impairments and functional deficits rather than diagnoses. This is to create the broadest “filter” for inclusion initially and narrow down from there who the device is appropriate for.
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DEB

13. Precautions and Contraindications
What are the contraindications?
Unresolved/resolving DVT
Open wounds
Active drug-resistant infection
Recent/unstable fracture, ie. any weight-bearing restrictions
And the precautions?
Osteoporosis/long-term use of osteoporosis medications
Consider this with all SCI patients
Unstable cardiovascular conditions/unstable for exercise
PAD (insufficiency) peripheral arterial disease
Incontinence (multiple patient use)
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DEB

14. Programmable Settings
Threshold
% of body weight needed to activate
Assistance
Amount of assistance provided during knee extension
Resistance
Amount of resistance provided during knee flexion
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DEB

15. Sit to Stand Stair Climbing Gait
Weight Shifting
The device is used to assist patients in performing more of any standing activity, from early attempts to get patients up from sitting, to facilitating better and more symmetrical LE weight bearing, to improving gait symmetry and endurance. It’s also very useful in progressing patients to stair climbing and getting back to reciprocal stair climbing.
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DEB

16. Supporting Principles of Motor Learning
Why Use the Bionic Leg?

17. Theories Have Evolved
Research in motor control/motor learning has more recently begun to make an impact on the practice of rehabilitation.
Rehabilitation typically focused on passive facilitation of isolated movements or teaching patients to compensate for lost movement
Traditional view was that the motor cortex was static, with specific areas of the cortex dedicated to specific areas of the body. We now know this is not the case and that the firing patterns within the cortex are plastic and changeable and that they change based on the activities that are performed.

18. Neural circuits not actively engaged for an extended time degrade.
Use It or Lose It
Neural circuits not actively engaged for an extended time degrade.
Use It & Improve It
Plasticity can be induced in specific areas of the brain with extended training
Specificity
Neural changes are dependent on specific types of experience
Repetition
Permanent change is dependent on sufficient repetition
Intensity
Low intensity repetition = weakened response
Higher intensity = long-term changes
Time
Learning is most effective when training begins soon after injury
Salience
Tasks that have meaning to the learner promote better learning

19. In a review of rehabilitation approaches after neurological injury, the greatest improvements were seen with high intensity, repetitive, task-specific interventions, regardless of impairment or technique being used
Task Specific
High Intensity
Repetition
Motor Learning
TASK SPECIFC! The tasks practiced must be as close to the real world task as possible. Practicing isolated movements only leads to improved ability to perform those isolated movements. Therefore, rehab activities must be structured to maximize practice of varied and functional tasks. The BL allows for exactly this process – greater repetitions of higher-level functional activities.

20. Use It or Lose It Bionic Leg –
Facilitates use of involved limb during mobility tasks.
Drives increased engagement and attention of involved side.
Volitional movement required to activate device
Increased (customized) threshold = increased initiated movement of involved limb required to activate device.
By facilitating active use of the involved limb, we are achieving task specific practice and can then customize the settings to appropriately and progressively challenge the patient. The therapy can be progressed to remain challenging for the patient as mobility improves.

21. Repetition
The lesson is that there are multiple limiting factors in completing high levels of repetition. Patient weakness and fatigue, therapist fatigue and both patient and therapist safety. We know it requires very high repetitions to learn new tasks, so the BL allows us to safely complete more repetitions than could otherwise be completed.

22. High Repetitions Intensive practice means tons of reps…hundreds a day
Canning C, et al., A randomized controlled trial of the effects of intensive sit-to-stand training after recent traumatic brain injury on sit-to-stand performance, Clinical Rehabilitation, 2003; 17:
24 subjects randomized (11 control/13 experimental)
Trained over four weeks
Targeted 100 reps of sit to stand and 60 step ups per day; five days a week
Varied chair and step height over the four weeks
62% improvement in motor performance (sit to stand) for experimental compared to 18% for control.
In addition to their usual rehabilitation
Program subjects in the experimental group participated in 4weeks of intensive training of sit-to-stand and step-up exercises
The control group did no additional sit-to-stand or step-up training.

23. Sensory Input/Feedback
Feedback can enhance motor learning
Self correction occurs when user applies feedback to performance enhancement
Focuses users attention
Feedback comes in many forms – including visual – consider videotaping your clients before and after device use
Van Vliet P, et al., Extrinsic feedback for motor learning after stroke: What is the evidence?, Disability and Rehab, 2006; 28(13-14):
Engardt M, et al., Vertical ground reaction force feedback to enhance stroke patients' symmetrical body- weight distribution while rising/ sitting down., Scand J Rehab Med 1993; 25:41-48.
Feedback is a key component to motor learning. Patients learn best when they are able to self correct in response to feedback. The device provides sensorimotor feedback, audible feedback and proprioceptive feedback during exercise. These afferent inputs are frequently missing in many neurologic conditions so use of the device give greater CNS input than is received without the BL.

24. Clinical Studies

25. Clinical Evidence: Summary of Findings
UCSF
Increased endurance, gait speed, stride length
With carryover – improvements maintained post therapy
Columbia University
Improvements in endurance, gait speed, balance
Again, maintained after the treatment - Carryover plus continued improvement
Tested 1 month and 3 months post treatment
University of Florida (Publication pending)
Improved Antero-Postero Stability, i.e. decreased fall risk
EMG phasing improved toward “normal” or less compensatory
Two published and one pending study completed. Multiple single-patient case studies underway in a constant effort to create treatment examples and protocols.
UCSF and Columbia looked at chronic CVA patients – notorious for plateauing in therapy and regressing over time. Difficult to change ingrained patterns but patients were able to make gains.

26. Outcomes from UCSF Study
10 meter walk test
Pre
Post
+1 month
% Change
Patient 1 (5 yrs post)
.59 m/s
.81 m/s
.95 m/s
61%
Patient 2 (1.5 yrs post)
.29 m/s
.43 m/s
.45 m/s
55%
Patient 3 (10 yrs post)
.83 m/s
1.03 m/s
1.14 m/s
37%
6 min walk test
Pre
Post
+1 month
% Change
Patient 1 (5 yrs post)
170 m
207 m
250 m
47%
Patient 2 (1.5 yrs post)
93 m
140 m
123 m
32%
Patient 3 (10 yrs post)
271 m
300 m
285 m
5.2%
Significant gains in therapy were maintained after the therapy was stopped – evidence of not just motor performance but motor learning, i.e. carryover.

27. Clinical Results International Conference on NeuroRehab
Acute carryover in balance scores, stability in stance
“The BL allows the user to involve their weaker leg more than would otherwise be possible...”
Transfers
Largest Studies to Date
Gait
Significant improvement in muscle engagement by EMG
Symmetry of motion altered towards healthy
“Changes post-stroke are consistently present and alter EMG towards normal…”
Looked at more acute CVA patients in a more controlled gait lab that could measure gait symmetry, stability and muscle engagement via EMG.

28. Shepherd Center – TBI Case Study
23 y/o female s/p MVA
Multiple skull fractures, L temporal SDH, IPH pons, midbrain, R cerebellar peduncle
Patellar fracture, left transverse process fracture T1
Patient presented with:
severe left hemiplegia poor spatial awareness
mild left neglect poor visual acuity
mild pushing tendencies

29. Mod/Max 2-3 (ARJO UE Support) 2 Min A (sit pivot) Mod A
Initiated use of Bionic Leg 6 weeks post-admission
(1 day after emergence from coma)
2-3 times per week for functional gait skills.
Transfers
Sit/Stand
Gait 1
Max A (sit pivot)
Dependent
Mod/Max 2-3 (ARJO UE Support) 2
Min A (sit pivot)
Mod A
Dependent (ARJO < 50ft)
Min A x 2 3
Min A (stand pivot)
Min A
Min A x 2 > 100 ft 4
Min A ft (no BL)

30. Activities 1
Pre-gait stance control, weight shifts, very limited gait (step-to pattern) Pusher Syndrome behaviors noted 2
Stance control, kicking ball with unimpaired LE while maintaining stance on left (20-30 reps), anterior weight shifts in sit/stands for increased symmetrical weight bearing during transitional movements, gait (step-through) 3
Continued ball kicks for weight acceptance left LE, lateral weight shifts to left, gait in open environments, stair training 4
Gait training without device, *no pushing behaviors noted

31. Questions & Answers