Transcript AlterG Bionic Leg

Dan Lewis, PT
Deb Soares OTR/L
AlterG Products
AntiGravity
Treadmill
AlterG
Bionic
Leg
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Potential Influence of AlterG Technology
AlterG Bionic Leg &
AlterG Anti-Gravity
Treadmill
Reduce Support (BW %,
Threshold, Assistance)
Motor and Sensory
Input
Increased ROM,
strength
Improved Performance
Varied repetition at limit
of performance.
Feedback from
successful performance
Neuroplasticity/ Motor
Learning
AlterG Bionic Leg
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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
Dynamic, “As Needed” Assistance
Weight shift triggers:
Assistance (stand)
Resistance (sit)
Stabilization (walk)
Easily Programmable to Match
Patient’s Functional Level
Leg Specs
• Leg weight approx. 8 lbs.
• Minimum to maximum patient height 5’-6’6”
• Minimum to maximum weight appx 100-300 lbs.
• Battery life-1-2 hours, requires only 45 min to charge
• Foot sensors 4 sizes each side, total of 8 included
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
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
Maximizes Inputs Needed for Effective Therapy
Improves
Confidence
Increases
Intensity,
Engagement
Corrects
Biomechanical
Movement
Maximizes
Repetitions
Effective,
Durable
Therapy
First patients: (57 Year old, 8 Years s/p stroke)
Before - “Compensatory for Life”
Initial assessment
After 4 weeks, 2 sessions/week
1 month after end of treatment
After - “Independent Safety”
Ambulation (m/s)
.05
.13
.17
Endurance (m)
23
38
66
Berg Balance
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40
50
Today, 2 years post study: .45
m/s
CVA
TBI
Incomplete
Spinal Cord
Injury
Parkinson’s
MS
Post-hip or
knee
replacement
DIAGNOSES
Difficulty
with sit to
stand
Poor gait
symmetry
Decreased
standing
tolerance
Flexed
posture
Stairs
FUNCTIONAL DEFICITS
IMPAIRMENTS
Lower extremity weakness
Decreased stance stability
Decreased standing
tolerance
Ataxia
Asymmetrical weightbearing
Decreased active knee
extension
Decreased terminal knee
extension control
Decreased
proprioreception/sensation
Inattention/neglect
*Balance dysfunction
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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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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Weight Shifting
Sit to Stand
Gait
Stair Climbing
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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
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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
Time
Salience
• Low intensity repetition = weakened response
• Higher intensity = long-term changes
• Learning is most effective when training begins soon after
injury
• Tasks that have meaning to the learner promote better learning
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
Repetitio
n
Motor
Learning
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.
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Repetition
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; 17:355-362.
• 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.
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):
831-840.
• Engardt M, et al., Vertical ground reaction force feedback to enhance stroke patients' symmetrical bodyweight distribution while rising/ sitting down., Scand J Rehab Med 1993; 25:41-48.
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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
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Outcomes from UCSF Study
10 meter walk test
Pre
Post
+1 month
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
% 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%
Clinical Results
International Conference on NeuroRehab
Transfers
Gait
• Acute carryover in balance scores, stability in
stance
• “The BL allows the user to involve their weaker
leg more than would otherwise be possible...”
• Significant improvement in muscle engagement
by EMG
• Symmetry of motion altered towards healthy
• “Changes post-stroke are consistently present
and alter EMG towards normal…”
Largest Studies to Date
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
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• 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
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Max A (sit pivot)
Dependent
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 (stand pivot)
Min A
Min A 1-2 200-300ft (no BL)
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Activities
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Pre-gait stance control, weight shifts, very limited gait (step-to
pattern) Pusher Syndrome behaviors noted
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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
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