Motor control and therapeutic rehab models

what is motor control?

the ability to regulate or direct the mechanisms essential to movement

what impacts movement?

task, individual, and environment

what are the individual constraints on movement?

• perception: integration of sensory information

• cognition: attention, planning, etc

• action: activity to perform

what are the task constraints on movement?

different tasks require different degrees of motor control. therefore we can classify tasks in groups that may help guide therepy based on the level of difficulty of the task for the patient. we can do this through closed predictable task environment vs open predictable task environment and stability tasks vs mobility tasks

what makes up the physiology of motor control?

sensory/perceptual systems, visual systems, vestibular system, action systems

what makes up the sensory/perceptual system?

• muscle spindles: detect changes in muscle length

• GTOs: sense changes in muscle length and inhibit the antagonist when stretched at rest in order to protect from injury

• joint receptors: sense changes in joint angle

• cutaneous receptors: mechano, thermo, and noci

• dorsal spinal pathway: proprioception and light touch

• lateral spinothalamic: pain and temp

discuss the visual system

• helps identify objects in space

• where we are in space

• motion

• where are body parts in relation to each other

what does the action system include?

motor cortex, brainstem, cerebellum, and basal ganglia

what are the primary roles of the different parts of the action system?

• premotor cortex: plans movement using external/sensory cues

• supplementary motor area: plans and sequences internally guided movement

• primary motor cortex: executes skilled voluntary movement and contributes to force and movement speed

• basal ganglia: selects/scales desired movement and suppresses competing movement

• cerebellum: compares intended vs actual movement; coordinates timing and accuracy; controls motor learning

• brainstem: regulates posture, balance, tone, orientation and background motor control

what are the key inputs/outputs of the different parts of the action system?

• motor cortex: motor cortex —> brainstem/spinal cord

• premotor cortex: sensory/visual information —> motor cortex

• supplementary motor area: internal motor plans —> motor cortex

• basal ganglia: cortical— BG—thalamic loops

• cerebellum: sensory + motor information —> motor systems

• brainstem: descending pathways —> spinal cord

how do we see the action system in action when performing a goal directed movement?

1. integrate using the sensory systems

2. plan and select using the premotor + SMA + basal ganglia

3. execute movement using the primary motor conrtex and corticopsinal tract

4. stabalize using the brainstem and spinal cord

5. coordinate and adapt using the cerebellum

what are the traditional models of motor control?

• reflexive model

• heirarchical model

• motor programming model

what is the core concept of the reflexive model and its key assumptions?

core concept: movement is produced by sensory stimuli that trigger reflexive motor responses. so, movement is triggered

key assumptions:

• sensory input is the primary driver of movement with a stimulus activating a specific motor response. so, movement is primarily reactive

• more complex movements develop through a chain of reflexes with one reflex providing the stimulus for the next reflex in the sequence. therefore, reflexes can be linked to movement sequences

• therapist driven in order to elicit the good reflexes and inhibit the bad

bottom line: movement is a response to sensory input… stimulus —> reflex response

—> movement

what are the limitations/criticisms of the reflexive model?

it does not adequately explain voluntary movement without an external stimulus, novel movements, or movements that occur too rapidly to depend on continous sensory feedback

what is the core concept of the heirarchical model and it’s key assumptions?

core concept: movement is organized in hierarchy of nervous system control, progressing from higher to lower centers. so, movement is directed

key assumptions

• higher centers are responsible for complex, voluntary movement that plan and direct the movement and determine the goal

• lower centers are responsible for increasingly automatic and reflexive aspects of movement, help organize and execute motor responses, and produce more stereotyped patterns of movement

what are the pros of the heirarchical model?

• demonstrates several levels of control to initiate interventions

• prevent primitive reflexes from taking over to allow equilibrium reactions

• reduce the hyperactive stretch reflex to allow for coordinated movement

what are the cons of the heirarchical model?

• overemphasizes top down control

• underestimates sensory and environmental influences

• does not fully explain automatic movement

• does not adequately explain movement variability

• views reflexes as primarily lower level behaviors

• cannot fully explains recovery after CNS injury

what is the core concept of the motor programming model and key assumptions?

core concept: the CNS contains motor programs which are preorganized patterns of movement that can be activated to produce coordinated actions. so, movement is organized.

key assumptions: it is believed that these motor programs organize the timing and sequence of movement, coordinate gropus of muscles as a functional unit, can be initiated with limited sensory input, and can be modified by sensory feedback and environmental demands

what are the limitations of the motor programming model?

it does not fully explain how novel movements are produced or how the taks, individual, and environment interact to shape movement

what are the traditional rehab models?

1. Brunnstrom therapy

2. Rood’s approach

3. PNF

4. Neurodevelopmental

what are the principles of Brunnstrom therapy?

• synergies are the restul of decreasec cortical control

• synergies are a normal part of recovery

• reflexes and synergies should be elicited early in treatment

• synergies are strengthened to improve voluntary movement

• once synergies are in place, repress them to obtain voluntary movement

• resistance is applied to weak components of synergies

• sensory stimuli are applied to obtain reflexes and produce movement

when and why are the Brunnstrom stages used?

to predict recovery in the UE (typically) versus the need to compensate

what are the 7 Brunnstrom stages?

1. Flaccidity, no reflexive or voluntary movement

2. spasticity begins, associtaed reactions and reflexes begin, may have minimal volitional movement so this is primarily reflexive at this point

3. spasticity peaks, voluntary control begins but locked into synergies so now ALL movements are synergistic

4. some movement combinations begin that are not full synergies. spasticity begins to decline

5. more difficult movement combinations begin to occur

6. “normal” motor function occurs but the quality of the movement may decline with speed or full coordincation not present

7. normal movement occurs

what is the biggest problem with Brunnstrom therapy?

it drives plasticity toward abnormal movements so it becomes habitual and then we try to break these habits which is really hard to do

what is the basis of Rood’s approach?

• it is based mostly on the reflexive model so it emphasizes the use of a motor developmental sequence and sensory stimulation through reflexes (so quick stretch, tapping, prolonged stretch, etc)

• also based on the heirarchical model so they say all patients must progress through the developmental sequence in order to develop a heirarchy of skills

what are the 4 stages of Rood’s approach?

1. Mobility (ROM)

2. Stability: ability to maintain the ROM and stay stable with movement

3. Mobility (moving off BOS): so the ability to control the motion

4. skill (functional activity)

what are the limitations of Rood’s approach?

• developmental sequence is not necessary

• the use of reflexes to stimulate or inhibit muscles has several limitations such as short contractions, a poor carry over to home, and stimulates only one muscle group

discuss PNF

• it promotes movement facilitation, inhibition, strengthening, and relaxation

• uses graded contractions of all types

• discourages abnormal synergies and encourages combined/normal synergies

• incorporates both the reflex based model and developmental sequence

• impliments part task training

• repetition is important

• promotes Rood’s stages

what are the strengths of PNF?

• uses mulitplanar, diagonal movement patterns

• uses proprioceptive, tactile, visual, and verbal input

• can facilitate muscle activation, strength, coordination, and motor control

• allows the therapist to use stronger components to facilitate weaker components

• can address mobility and stability within the same treatment approach

• techniques can be incorporated into functional activities and other treatment approaches

what are the limitations of PNF?

• don’t always translate to task specific activities

• requires active participation and the ability to follow commands

• can be difficult with significant cognitive, communication, or perceptual impairments

• sometimes requires a lot of therapist skill and handling

• should not replace task specific, repetitive practice

discuss neurodevelopmental therapy (NDT)

utilizes the sensorimotor sensory feedback loop to describe the development of motor skills

key elements:

• inhibit abnormal msucle tone and synergies

• promote normal movement patterns

• goal is to optimize function

• prioritize treating the patient in the higest possible functional position to challenge movement. ex: if they can stand, then treat them in standing

what are the key NDT principles?

minimize compensations with the sound side and reinforce the use of the affected side in all functions as early as possible.

broken into two phases:

1. preparatory phase: helps increase joint mobility and facilitate postural alignment

2. faciliation of active movement: therapist provides sensory input and uses key point of control to help facilitate the movement

what are reflexive inhibiting patterns and why do we use them?

the opposite position from the spastic resting patterns in order to prevent shortening and decreased ROM overtime

what are active movement synergies vs resting spastic patterns?

active synergies: abnormal predictive pattern seen with active movement

resting spastic pattern: abnormal predictive pattern at rest that prevents someone from moving normally

what is the reflex inhibiting patterns of the UE?

• scapular protraction

• shoulder external rotation

• shoulder abduction

• elbow extension

• wrist and finger extension

• forearm supination

what is the reflex inhibiting patterns of the LE?

• pelvic forward rotation

• hip flexion

• hip abduction

• hip neutral rotation

• knee flexion

• ankle dorsiflexion

• forefoot pronation

what is NDT task analysis?

being able to look at a movement and tell why they may be choosing to move the way they are— what is preventing them from normal movement

what are the limitations of NDT?

• research supports reducing focus on inhibition of spasticity

• strengthening with resistance including strengthening of weak muscles should be included

• excessive handling which does not promot errorful learning and will reduce carry over and should be used sparingly

what are the contemporary models of motor control?

1. systems/dynamic systems model

2. modular model

3. ecological theory

discuss the systems/dynamic systems model of motor control

• core concept: movement emerges from the interaction of multiple systems and constraints simultaneously. it is not controlled by one system or one level of the CNS

• movement reflects interaction amont the individual, task, and environment

• the importance of each system changes depending on the task so movement solutions are flexible and variable

• changing constraints can reorganize movement

how can we apply the systems/dynamic systems model of motor control to practice?

• manipulate the person (strength, ROM, sensation, balance, cognition, motor control), task (goal, speed, accuracy, complexity), or environment (surface, obstacles, lighting, support, distractions

• allow the patient to explore movement solutions— they need to know how to correct themselves and we need to let them

• practice meaningful tasks in variable contexts

• encourage adaptibility rather than one correct movement pattern

discuss the modular model of motor control

• it says the the CNS simplifies movement by organizing muscles into functional modules or synergies in order to provide coordinated movement

• a module represents a coordinated movement pattner of muscle activation. because our body has many degrees of freedom, these modules can be combined, scaled, or timed differently and be modified by different sensory inputs and task demands

after CNS injury, modular organization becomes altered as they are recruited less frequently or have reduced flexibility leading to abnormal synergies. so, how can we apply the modular model to practice?

• do not evaluate a muscle only in isolation but examine coordination across muscles and joints

• practice tasks requiring different combinations of movement

• vary task demands to encourage flexible recruitement and adaptable motor solutions

what is the ecological theory of motor control?

• core concept: movement is shaped by what the environment offers and what the individual percieves as possible. so, movement is fueled by perception of opportunities for action

• emphasizes affordances and environmental information

• movement is specific to the person, task and contect

• exploration supports adaptable movement solutions

what is the contemporary rehab model we use today?

Carr and Shepherd

what are the principles of Carr and Shepherds rehab model?

• focuses on the understanding of abnormal movement and how movement is learned or re learned

• an adult who has experienced a neurological insult may no longer remember how to move and may have to relearn the appropriate movement patterns

• this approach is based on the systems model of motor control as it is a fairly pure motor learning model of treatment

what are the 12 core concepts of Carr and Shepherd model?

1. identification of a motor goal or task

2. analysis of the task and what is required

3. appropriate alignment and biomechanical position

4. stability before mobility

5. practice of task (practice and feedback variables; movement is stimulated by action)

6. inhibition of abnormal movement using verbal commands and feedback

7. motivation: task must be challenging but success must be achievable

8. reflexes are not used in treatment at all

9. the patient is encouraged to develop their own solutions to motor problems

10. patient handling is very minimal

11. repetition is crucial and more therapy per day with more repetition even in groups is advocated

12. circuit training to increase strength of weak muscles is advocated

what are the limitations of the Carr and Shepherd model?

• few specific treatment ideas to address patients with very low tone, severe weakness or problems such as ataxia, apraxia, etc

• not effective on patients who are unable to follow commands or with limited ability for cognitive processing since it is heavily based on problem solving and verbal cueing

what is the integrative model that we use now?

1. analyze patient in the context of the task to be done

2. do we remediate or compensate?— often times its a combo of both

3. prevent secondary complications— falls, pressure sores, mental health, contractures, pneumonia

4. follow Rood’s 4 stages of motor control

5. be task specific

6. use neuroplastic principles

7. incorporate intense endurance/strengthening

8. promote normal movement patterns and sensory input