Motor Control and Learning - vtapta€¦ · • Write your name – Change limb – Change force...

10/20/2017

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The heart and science of medicine.

UVMHealth.org/MedCenter

Motor Learning In Ortho and Beyond

Jon Robinson PT, DPT, NCS

Clinical Lead Physical Therapist

University of Vermont Medical Center

• Medial collapse in running

Movement Dysfunction



Willy et. al. Clin Biomechanics 2012

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• Ability to regulate or direct the mechanisms essential to movement.

• How all kinds of movements are controlled, body segments

coordinated/organized to produce movement, particularly given

degrees of freedom

• How the CNS is organized so that many individual muscles and

joints become coordinated

• How sensory information is used in the control of movement and how this information allows a person to select and plan an action.

Motor Control

Motor Control Theory

� How you think the system works directly influences how you prioritize and implement treatment when the system malfunctions

• Degrees of freedom

– Multitude of independent ways a system can act

• How can degrees of freedom be best organized to achieve goal?


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• Theories must account for behavior

• Movements are:

– Flexible

– Unique

– Consistent

– Modifiable


Borghese et al. J Physiol 1996

• General Motor Programming Theory

• Dynamic Systems Theory

• Uncontrolled Manifold Hypothesis


• Movement planning & execution are responsibility of cortical command centers

• Movements stored in form of Generalized Motor Program (GMP)

General Motor Program Theory

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• Write your name

– Change limb

– Change force

– Change speed

Motor Equivalence

Schmidt & Lee, Motor Control and Learning, 2005

• Abstract representation of stored pattern for class of actions

• Pre-structured set of movement commands

• Organizes many degrees of freedom into single unit for efficient and effective action

• Invariant features: stored

• Relative timing & sequencing

• Parameters: modifiable features of GMP

– Time/speed

– Amplitude

– Effectors

Generalized Motor Program

• What are the potential implications of interventions with regard to motor control?

Implications

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• Motor behavior emerges from interaction of multiple subsystems

• Actions shaped by intention of performer and constraints of environment

• System self-organizes

– Order parameters of coordination

– Control parameters of context

– Organized based on attractor state of

efficiency & low variability

Dynamic Systems Theory

• Perception-action coupling

– The coordination of the visual perception of the relevant external

stimulus and the movement required to achieve the action goal.

– Our perception of important factors in the environment and our

abilities paired against the environment drives movement

– Tau

• Time to contact is specified according to the relative rate of change

of the size of the image of the object on the retina of the eye.

• Obstacle clearance

• Reach to grasp

Dynamic Systems Theory

Attractor States

Transition

In-Phase

Anti-Phase

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Comparison

GMP Dynamic Systems

Invariant features of coordinationstored in CNS

Parameters of speed, force, amplitude, and

limb added to generate schema

Control parameters of speed, force, amplitude,

goals, mechanics

Order parameters of coordination organized based on attractor state of stability & efficiency

• More variability in segment orientation/joint displacements than in endpoint position.

• Some of this variability contributes to the task goal, some does not.

• The set (manifold) of system configurations (neurons, muscles, joints) that do not change the outcome measure of performance (e.g., endpoint position) are not controlled. Schoner, Ecol Psych, 1995

• This allows flexibility & adaptability of movement.

Uncontrolled Manifold Hypothesis

Joint displacement

variability

Uncontrolled Manifold Hypothesis

Hammer endpoint

variability

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• How is movement controlled once initiated?

– Closed-Loop

– Open-Loop

Controlling Movement

• Use of feedback, error detection & correction to maintain desired goal

Closed-Loop Control

control

center

commands

feedback

effectors

comparator

• Centrally determined, pre-structured commands to effectors without use of feedback during movement

Open-Loop Control

control

centereffectors

commands

feedback

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Field of Dreams

• If you build it, they will use it…right?

Field of Force Production

• Motor Performance

– Observable behavior/skill execution at a specific moment in time

• Motor Learning

– set of processes associated with practice leading to a relatively permanent change in the capability for responding. (Schmidt & Lee,1998)

• Relatively permanent change in motor behavior

• Inferred from repeated observations of performance

• Promoted through practice or experience

• Motor Adaptation

– modifying an already well-learned motor skill that occurs over a period of trial and- error practice when exposing the skill to a novel, perturbing context or environment (Martin, Keating et al. 1996).

• With sufficient practice adaptation becomes separate and discrete motor plan that can be called upon when conditions are met (motor learning).

Learning vs. Performance

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Task/Learner/Environment

Environment Task

Learner

• Performance improvement

• Consistency

• Persistence

• Adaptability

– change in movement characteristics

• Stability

– change in task conditions

Characteristics of Motor Learning

• Acquisition

• Consolidation

• Learning

• Retention

– Ability to perform skill following period of no practice

– Measures persistence

• Transfer

– Ability to perform skill in altered environmental contexts, altered

levels of arousal and with altered movement characteristics

– Measures stability and adaptability

Assessment of Learning

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Retention Test

Transfer Test

• Neural correlate of learning

– Change within synapses: more synaptic receptors and

neurotransmitter vesicles increase the post-synaptic response to

the same input.

– Dendritic Spine proliferation

– Change in the area of cortical somatotopic representation

Neuroplasticity

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• Repetition matters

– Amount of practice single most important variable impacting

learning (Schmidt & Lee, 2011)

• Task specificity matters

– Skill acquisition

Neuroplasticity

Stages of Learning

Early Middle Late

Fitts &

Posner

Cognitive

• Attention/cognition-

heavy

• Trial strategies

• Limit DOF

• Large errors

• Variable performance

• Fast progress

Associative

• Refine skills

• Less attention-

dependent

Autonomous

• Increase automaticity

• Fine tune for different contexts

• Able to dual task

• Manage task & body efficiency

Systems

Theory

Novice

• Inefficient

• Inflexible

• Limit DOF

Advanced

• Open up DOF

• More adaptable to

envt & task

changes

Expert

• Able to use all DOF

• More efficient, coordinated,

flexible

• Take advantage of biomechanics

Gentile Initial/Conscious

• Goals: understand

task goals & dynamics

• Start to recognize

relevant factors in

envt

Later/Non-conscious

• Optimize force production & timing

• More consistent, efficient & flexible

• Fixation for ‘closed skills’,

diversification for ‘open skills’

Overview

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Skill Definitions & Motor Control• Skill Classification• Control Theories

• Neural Basis

• Motor Planning

The Goal!

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• A motor skill represents learned processes of motor control that produce a coordination of voluntary movements to achieve a goal.

Motor Skill Classification

• One Dimensional

– Fine/gross

– Discrete/serial/continuous

– Open/closed environment



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Self-paced

Fixed Environment

Highly Predictable

Closed Skill

Externally-paced

Changing Environment

Open Skill

• Focalization of awareness

• Capacity is limited but not fixed

• Capacity and demand change

– Task/context requirement

– Skill level of the performer

Attention

Attention

https://www.youtube.com/watch?v=vJG698U2Mvo

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• Bottom up

– Directed toward novel or highly familiar/meaningful stimuli

• Top down

– Specific intention or direction

Selective Attention

Selective Attention

Feeling of grip force

Feel of the full golf

swing

The back rim of the

golf hole

The entire green

narrow broad

external

internal

3 6 5 2 9 4 9 1 7 0 9 4

7 5 2 9 7 2 1 5 4 3 2 6

Memory

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How many single digits did you remember?

A. ≤ 4

B. 5-6

C. 7-8

D. 9-10

E. > 10

Memory

Memory

632 145 729 527

904 179 294 452

How many single digits did you remember?

A. ≤ 4

B. 5-6

C. 7-8

D. 9-10

E. > 10

Memory

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• 3 Systems

– Sensory Register

• Large capacity

• Short duration (250 ms)

– Working memory

• Small capacity (7 ± 2)

• Short duration 20-30 s

– Long-term memory

• Limitless capacity and duration

Memory

• decision making

• comparisons

• problem solving

• interactive workspace

Memory

Sensory

Register

Working

memory

Long-term

memory

Selective

attention Rehearsal

• Implicit (How)– Procedural

• Declarative (What)– Episodic

– Semantic

• Is declarative memory is essential for motor skill learning?

Memory

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• Demonstration

• Instructions

• Feedback

• Practice Organization

• Practice Distribution

• Mental Practice

• Focus of Attention

• Enhanced Expectancies/Motivation

• Autonomy

Optimizing Motor Learning

• Demonstration

• Instructions

• Feedback



• Mental Practice



• Autonomy


Demonstration

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• Skilled/perfect demonstration or unskilled/peer?

• How could we do this with our runner?

Demonstration




• Skilled/perfect demonstration

– Allows learning of invariant features of task

• Unskilled/peer demonstration

– Allows for identification of movement errors and facilitates

problem-solving

– Enhanced self-efficacy from “like” model

Demonstration

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• Intrinsic

– Available from sensory input

• Extrinsic/augmented

– Information from external source to supplement intrinsic

feedback

Feedback

• Essential

– When task-intrinsic feedback is not available or unidentifiable

• Unnecessary

– when task-intrinsic feedback sufficient/redundant

• Enhances

– During performance plateau or with new, complex coordination,

or if enhances motivation

• Hinders

– If individual becomes over-dependent, exceeds attention

capacity, diminishes motivation or promotes performance over

learning

Augmented Feedback

• Type– Knowledge of results (KR) – often apparent and redundant– Knowledge of performance (KP)– most helpful

• Timing– Concurrent vs terminal

• Concurrent often improves performance during practice but not on retention/transfer test

• Gap between performance and terminal feedback can allow for greater problem-solving of movement errors

• Frequency– Continuous

– Faded

– Bandwidth– Learner-regulated

Feedback

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• Impact of feedback frequency on learning

Retention Test

• Dobkin BH, Plummer-D'Amato P, Elashoff R, Lee J. International randomized clinical trial, stroke inpatient rehabilitation with reinforcement of walking speed

(SIRROWS), improves outcomes. Neurorehabilitation and neural repair. 2010;24(3):235-242

• Quantitative terminal feedback provided on gait speed vs no feedback (n=179)

• Reinforcement provided vs no reinforcement

– “Very good! You walked that in (number of) seconds.”

• “This is better by (number of) seconds”

• “This shows you are holding your own”

• “I believe that you will soon be able to walk a bit faster.”

• Treatment group walked significantly faster at discharge

– Walking speed at discharge (.91 v .72 m/s, p = .01) (21% difference between groups equal at admission)

– Walking speed at 3 months post-discharge (p = .03)

Feedback

• “Forcing the learner to actively develop problem-solving strategies independently of the guidance provided by…the therapist is actually beneficial for motor learning.” Carolee Winstein, PTJ 1991

Feedback

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• Variability of practice

– Contextual Interference (CI)

– Variable practice promotes adaptability

– Continuous search for task solutions

– Enhances capability to select appropriate parameters for context

Practice Organization

• Contextual Interference (CI)

– Practice performance disruption from performing multiple skills

or variations

• Blocked/constant practice

– Low CI

– Better for performance

• Random/variable practice

– High CI

– Better for retention and learning


• UE prosthetic training; Weeks, Wallace, and Anderson (2003)


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• 3 Tasks:

• Pipe transfer

• Nut off hook

• Electrical Plug

• 2 days acquisition

• Blocked vs random

• Retention

• congruent vs incongruent

retention of blocked or

random

• Transfer 3 new Tasks:

• Sphere transfer

• Simulated feeding

• Padlock Opening

Weeks et al. 2003b

• Influence of previous experience on performing a new skill or skill in new context

Skill Transfer

Which might provide the most successful transfer to independent bicycling?

Push Bike

Training Wheels

Skill Transfer

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• Similar movements foster positive transfer.

• Different movements in similar environments foster negative transfer.

Skill Transfer




• Is all running the same?

– Uphill

– Downhill

– On level

– On treadmill

– Overground

• Will strength gained in one task transfer to use of strength in another task?

Transfer and Practice Organization

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Medial Collapse

• The effect of a hip strengthening program on mechanics during

running and during a single leg squat Willy RW, Davis IS. J Orthop

Sports Phys Ther. 2011 Sep;41(9):625-32.

– 20 female runners with excessive hip adduction – uninjured

– 6-week intensive hip strengthening program

– Last 4 weeks: functional strength training

Skill Transfer and Task Specificity

• The effect of a hip strengthening program on mechanics during

running and during a single leg squat Willy RW, Davis IS. J Orthop Sports

Phys Ther. 2011 Sep;41(9):625-32.

– Significant 23% improvement in hip strength

– Significant improvement in single leg squat hip mechanics (Hip ABD, hip

IR, contralateral pelvic drop)

– No change in gait kinematics during running

• Demonstration

• Instructions

• Feedback



• Mental Practice



• Autonomy


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OPTIMAL Theory

• Internal focus

– Attention on body movements

• External focus

– Attention on effects of movements on the environment

Attentional Focus

Instructions that direct an individuals’ attention to the effects of their movements on the environment inducing an ‘external’ focus of attention, are more effective for learning than instructions that direct attention to the movements themselves, inducing an ‘internal’ focus

Internal or External

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Tasks– Balance

– Golf– Soccer kicks– Football kicks

– Volleyball serves– Dart throwing– Tennis

– Basketball free throws– Rowing– Swimming

– Weight lifting– Agility– Sprint

– Force production– Vertical jump– Playing musical instruments

External Focus

Skill Level– Novice

– Expert

Age Groups– Children

– Young adults

– Older people

Disabilities– Parkinson disease

– Stroke

– Injuries

– Intellectual disability

• Internal focus: “Focus on the swing of your arms”

• External focus: “Focus on the swing of the club”

External Focus

• Goal was to push with 30% of maximum force

• Provided with under/over on each trial with verbal feedback

– Internal focus: “push with the muscle of your calf”

– External focus: “push against the platform”

External Focus

K. R. Lohse, D. E. Sherwood, & A. F. Healy, 2011

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External Focus

• Wulf G, Chiviacowsky S, & Lewthwaite R. Altering mindset can enhance motor learning in older adults. Psychology and Aging. 2012;27:14-21.

Enhanced Expectancies/Motivation

• Intervention: “Active people like you, with your experience, usually do very well on this task.”

• Control

• Time spent in balance

• Palmer K, Chiviacowsky S, Wulf G. Enhanced expectancies facilitate golf putting. Psychology of Sport and Exercise. 2016;22(Supplement C):229-

232.


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• Palmer K, Chiviacowsky S, Wulf G. Enhanced expectancies facilitate golf putting. Psychology of Sport and Exercise. 2016;22(Supplement C):229-

232.


• Back to the stabilometer– Chiviacowsky S, Wulf G, Lewthwaite R, & Campos T. Motor learning

benefits of self-controlled practice in persons with Parkinson’s Disease. Gait & Posture. 2012; 35: 601–605.

Autonomy

• The Renoir Effect– Wulf G, Freitas HE, & Tandy RD. Choosing to exercise more: Small

choices can increase exercise engagement. Psychology of Sport and Exercise, 2014;15:268-271.

– Self-determined and selection of second task to perform

– Yoked

Autonomy

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Putting It All Together

• Willy RW, Scholz JP, Davis IS. Mirror gait retraining for the treatment of patellofemoral pain in female runners. Clin Biomech. 2012;27(10):1045-

1051.


Interventions

• Shown abnormal mechanics via baseline video (demo)

• Taught to activate glutes by ABD/ER against wall

• “Increase distance between knees”

• “point kneecaps straight ahead”

• Maladaptations: widening stance and toeing out

• Faded feedback

• No running outside of PT (CI)


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Medial Collapse

• Chiviacowsky, S., Wulf, G., & Lewthwaite, R. (2012). Self-controlled learning: the importance of protecting perceptions of competence. Frontiers in Psychology, 3, 458. doi:https://dx.doi.org/10.3389/fpsyg.2012.00458

• Dobkin, B. H., Plummer-D'Amato, P., Elashoff, R., & Lee, J. (2010). International randomized clinical trial, stroke inpatient rehabilitation with reinforcement of walking speed (SIRROWS), improves outcomes. Neurorehabil Neural Repair, 24(3), 235-242. doi:10.1177/1545968309357558

• Haggard, P., & Wing, A. (1997). On the hand transport component of prehensile movements. J Mot Behav, 29(3), 282-287. doi:10.1080/00222899709600842

• Lewthwaite, R., Chiviacowsky, S., Drews, R., & Wulf, G. (2015). Choose to move: The motivational impact of autonomy support on motor learning. Psychonomic Bulletin & Review, 22(5), 1383-1388. doi:https://dx.doi.org/10.3758/s13423-015-0814-7

• Lohse, K. R. (2012). The influence of attention on learning and performance: pre-movement time and accuracy in an isometric force production task. Hum Mov Sci, 31(1), 12-25. doi:10.1016/j.humov.2011.06.001

• Lohse, K. R., Sherwood, D. E., & Healy, A. F. (2011). Neuromuscular effects of shifting the focus of attention in a simple force production task. J Mot Behav, 43(2), 173-184. doi:10.1080/00222895.2011.555436

• Nijs, J., Meeus, M., Cagnie, B., Roussel, N. A., Dolphens, M., Van Oosterwijck, J., & Danneels, L. (2014). A Modern Neuroscience Approach to Chronic Spinal Pain: Combining Pain Neuroscience Education With Cognition-Targeted Motor Control Training. Physical Therapy, 94(5), 730-738. doi:10.2522/ptj.20130258

• Palmer, K., Chiviacowsky, S., & Wulf, G. (2016). Enhanced expectancies facilitate golf putting. Psychology of Sport and Exercise, 22(Supplement C), 229-232. doi:https://doi.org/10.1016/j.psychsport.2015.08.009

• Willy, R. W., & Davis, I. S. (2011). The effect of a hip-strengthening program on mechanics during running and during a single-leg squat. Journal of Orthopaedic & Sports Physical Therapy, 41(9), 625-632. doi:https://dx.doi.org/10.2519/jospt.2011.3470

• Willy, R. W., Scholz, J. P., & Davis, I. S. (2012). Mirror gait retraining for the treatment of patellofemoral pain in female runners. Clinical Biomechanics, 27(10), 1045-1051. doi:https://dx.doi.org/10.1016/j.clinbiomech.2012.07.011

• Winstein, C. J., & Schmidt, R. A. (1990). Reduced frequency of knowledge of results enhances motor skill learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16(4), 677-691. doi:10.1037/0278-7393.16.4.677

• Wulf, G., & Lewthwaite, R. (2016). Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning. Psychonomic Bulletin & Review, 23(5), 1382-1414. doi:10.3758/s13423-015-0999-9

References

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