neuro impairments: normal movement synergies

what is motor control

the process by which the brain organizes and regulates action of the muscular and skeletal systems, including movement and dynamic postural adjustments of a joint or body segment

when is motor control needed

1. to move a joint or body segment with quality

2. to stabilize a joint or body segment

motor control is impacted by what

MANY subsystems

ex: strength, ROM, muscle tone, cognition, environment, and task characteristics that influence the quality of movement

how do the individual, task, and environment contribute to motor control

1. individual: conceptualizes the movement

2. task: specifies the movement

3. environment: constrains or facilitates the movement

what are the components of task

1. mobility

2. stability

3. manipulation

   1. discrete vs continuous

   2. open vs closed

what are the components of environment

1. regulatory

2. non-regulatory

what are the components of an individual

1. action (muscle strength)

2. perception (feeling and knowing in environment)

3. cognition (following instructions)

how can the components of the individual change with CVA

1. lack sensation

2. lack muscle function

3. can’t understand instructions

what is pathophysiology

lesion in descending motor systems

what are primary neuromuscular impairments

caused by pathophysiology of lesion

ex: spasticity, paresis

what are secondary musculoskeletal impairments

come from/after the primary impairment

ex: structural and functional changes in muscles and joints, weakness, contracture, wounds

if a pt has a primary impairment of weakness (paresis), what are possible secondary impairments they may have

1. deconditioning and fatigue

2. contractures

3. edema

4. pain

5. osteoporosis

6. wounds/skin integrity

if a pt has a primary impairment of spasticity, what are possible secondary impairments they may have

1. contractures

2. postural changes

3. balance issues

4. pain

if a pt has a primary impairment of sensory loss, what are possible secondary impairments they may have

1. wounds

2. balance impairment

what is coordinated movement

the ability to execute smooth, accurate, controlled motor responses

within coordinated movement, the individual depends on input from

1. Perception

   1. somatosensory systems

   2. visual systems

   3. vestibular system

2. action

   1. neuromuscular system

3. cognition/language

an intact neuromuscular system for optimal movement includes

1. normal ROM

2. normal strength

3. normal motor control (coordination)

   1. smoothness, sequencing, timing, accuracy

what is smoothness

continual fashion without any interruptions in velocity or trajectory

what is sequencing

specific order of motor output required to achieve the intended goal of the action

what is timing

overall temporal structure of movement that includes relative percentage of time devoted to movement segments including initiation, execution, and termination

what is accuracy

closeness of a measured value to a standard or known value (freedom of error)

what contributes to normal sequencing

fractionated movement

what is fractionated movement

ability to selectively activate a muscle (or limited set of muscles) allowing isolated joint motion

ability of individual to move the target joint through very small fragments of available range even with large gross muscle groups

when does fractionated movement occur? how? result?

1. when: during volitional active movement

2. how: by activating a small fraction of the total motor units of a muscle group- can produce refined motor response

3. result: lots of different output patterns that change to meet the task demands

what contributes to abnormal sequencing

an abnormal synergy

what is an abnormal synergy

stereotypical movement patterns that cannot be changed and are not adaptable to changes in task or environmental demands

when does an abnormal synergy occur? how? result?

1. when: during volitional active movement

2. how: attempt isolated movement but can only move in abnormal unintended combos of muscle groups at multiple joints

3. result: obligatory mass movement pattern that can’t be altered to meet task or environmental demands

what are the abnormal synergies of the UE and which is more common

1. UE flexor synergy and UE extensor synergy

   1. UE flexor synergy is more common

what are the movements in a UE flexor synergy

1. Scapular retraction and elevation

2. shoulder ABD and ER

3. elbow flexion*

4. forearm supination

5. wrist and finger flexion

what movements are in a UE extensor synergy

1. scapula- protracted, downward rotation

2. shoulder- IR, ADD*

3. elbow- ext

4. forearm- pronation

what are the 2 types of LE synergies and which is more common

1. Flexor LE synergy and Extensor LE synergy

2. Extensor LE synergy is more common

what are the movements of an extensor LE synergy

1. Hip EXT, ADD, IR

2. knee EXT*

3. ankle PF and inversion

4. toe flexion (inconsistent, great toe may extend)

leg is functionally longer

what are the movements of flexor LE synergy

1. pelvis- elevation

2. hip- FLEX*, ABD, ER

3. knee- FLEX of knee to about 90

4. ankle- dorsiflexion and eversion

is there a relationship between synergies and weakness

no relationship between weakness or spasticity or presence of abnormal synergies

what does Brunnstrom’s stages of recovery test

fractionated movement continuum

flaccid- no movement or reflex

what is stage 2 of Brunnstrom’s stages of recovery

minimal to very limited voluntary movement in synergy or some components, spasticity begins

what is stage 3 of Brunnstrom’s stages of recovery

semi-voluntary, gains voluntary control in movement synergies only, spasticity at peak!

what is stage 4 of Brunnstrom’s stages of recovery

movement combos start outside of synergy with difficulty then increasing ease, spasticity declines but still present

what is stage 5 of Brunnstrom’s stages of recovery

more isolated moves are mastered out of synergy, spasticity continues to decline

what is stage 6 of Brunnstrom’s stages of recovery

fractionated movement approaches normalcy, no spasticity (except if move very fast)

what is stage 7 of Brunnstrom’s stages of recovery

normal- restoration of function, no spasticity

what is the fugl meyer assessment scale and what does it assess

1. performance based impairment index. Designed to assess motor functioning, balance, sensation, and joint functioning in pts with post-stroke hemiplegia

2. assess: fractionated movement vs abnormal synergy in UE and LE

3. scoring= 226 points (higher is better)

   1. UE motor= 66 points

   2. LE motor= 34 points

4. takes 45 minutes

what is our expectation with sequencing

1. perform selected components of the Fugl Meyer tests accurately

2. assess performance and identify which stage of recovery for the UE and LE the person demonstrates

what does a sequencing assessment allow you to answer

1. is my pt moving in a synergy

2. can they break out of synergy

3. can my pt perform (any) fractionated movement to allow them to function

how does recovery of sequencing occur

on a continuum - stage 1-7

not all people get to every stage

what are associated movements

1. unintentional movement of one limb that often occurs during the intentional movement of another limb

2. typical in hemiparetic extremities, when significant effort (force) is being generated; may also be seen on non-involved side

what is co-contraction/coactivation

simultaneous contraction of opposing muscle groups so the joint will not move in either direction

activation of both agonist and antagonist

what is co-contraction/coactivation a result of

the brains inability to:

1. precise activation of specific muscles

2. precise grading of muscle contraction

3. precise combos of muscles as they act together

what can co-activation be due to

CNS lesion but also present in unskilled early learning (ex: infant walking)

how is coactivation seen in LE of pts with cerebral palsy

in typical pts, there is no co-contraction of quads when hamstrings are contracting and vice versa

in pts with cerebral palsy, there is co-contraction of hamstrings when quads are contracting and vice versa

what is an abnormal posture

1. in individuals with stroke, most common example is stereotypic upper extremity posturing- shoulder abd, elbow, wrist and hand flexion

2. caused by continuous motor neuron activity

3. loos like synergy but seen at REST

what is decorticate posture

“C”

UE flexed- move in toward the cord

problems with cervical spinal tract or cerebral hemisphere

what is decerebrate posture

“E”

UE extended

problems with midbrain or pons

what is opisthotonic posture

everything is extended

what is timing problems

delayed movement initiation and reaction time

what are motor blocks/”freezing”

difficulty starting or continuing rhythmic repetitive movement, especially speech, writing, gait

difficulty with termination of movement

what are 3 examples of timing problems

1. hypokinesia

2. akinesia

3. bradykinesia

what is hypokinesia

slowness or poverty of movement, independent of any disturbance of muscle power (not related to strength)

what is akinesia

extreme lack of movement

what is bradykinesia

movement is very slow